Lactose Intolerance

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Posted by r2d2 03/30/2009 @ 08:15

Tags : lactose intolerance, allergies, diseases, health

News headlines
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Lactose intolerance

Lactose Intolerance by Region (African countries are only a rough guess)

Lactose intolerance is the inability to metabolize lactose, a sugar found in milk and other dairy products, because the required enzyme lactase is absent in the intestinal system or its availability is lowered. It is estimated that 75% of adults worldwide show some decrease in lactase activity during adulthood. The frequency of decreased lactase activity ranges from nearly 5% in northern Europe, up to 71% for Southern Europe, to more than 90% in some African and Asian countries.

Disaccharides cannot be absorbed through the wall of the small intestine into the bloodstream, so in the absence of lactase, lactose present in ingested dairy products remains uncleaved and passes intact into the colon. The operons of enteric bacteria quickly switch over to lactose metabolism, and the resultant in vivo fermentation produces copious amounts of gas (a mixture of hydrogen, carbon dioxide, and methane). This, in turn, may cause a range of abdominal symptoms, including stomach cramps, bloating, and flatulence. In addition, as with other unabsorbed sugars (such as sorbitol, mannitol, and xylitol), the presence of lactose and its fermentation products raises the osmotic pressure of the colon contents.

The normal mammalian condition is for the young of a species to experience reduced lactase production at the end of the weaning period (a species-specific length of time). In non dairy consuming societies, lactase production usually drops about 90% during the first four years of life, although the exact drop over time varies widely..

However, certain human populations have a mutation on chromosome 2 which eliminates the shutdown in lactase production, making it possible for members of these populations to continue consumption of fresh milk and other dairy products throughout their lives without difficulty. This appears to be an evolutionarily recent adaptation to dairy consumption, and has occurred independently in both northern Europe and east Africa in populations with a historically pastoral lifestyle. Lactase persistence, allowing lactose digestion to continue into adulthood, is a dominant allele, making lactose intolerance a recessive genetic trait.

Some cultures, such as that of Japan, where dairy consumption has been on the increase, demonstrate a lower prevalence of lactose intolerance in spite of a genetic predisposition.

Pathological lactose intolerance can be caused by Coeliac disease, which damages the villi in the small intestine that produce lactase. This lactose intolerance is temporary. Lactose intolerance associated with coeliac disease ceases after the patient has been on a gluten-free diet long enough for the villi to recover.

Certain people who report problems with consuming lactose are not actually lactose intolerant. In a study of 323 Sicilian adults, Carroccio et al. (1998) found only 4% were both lactose intolerant and lactose maldigesters, while 32.2% were lactose maldigesters but did not test as lactose intolerant. However, Burgio et al. (1984) found that 72% of 100 Sicilians were lactose intolerant in their study and 106 of 208 northern Italians (i.e., 51%) were lactose intolerant.

The statistical significance varies greatly depending on number of people sampled.

Chinese and Japanese populations typically lose between 20 and 30 percent of their ability to digest lactose within three to four years of weaning. Some studies have found that most Japanese can consume 200 ml (8 fl oz) of milk without severe symptoms (Swagerty et al., 2002).

Ashkenazi Jews can keep 20 - 30 percent of their ability to digest lactose for many years. Of the 10% of the Northern European population that develops lactose intolerance, the development of lactose intolerance is a gradual process spread out over as many as 20 years.

To assess lactose intolerance, the intestinal function is challenged by ingesting more dairy than can be readily digested. Clinical symptoms typically appear within 30 minutes but may take up to 1-2 hours depending on other foods and activities. Substantial variability of the clinical response (symptoms of nausea, cramping, bloating, diarrhea, and flatulence) are to be expected as the extent and severity of lactose intolerance varies between individuals.

In a hydrogen breath test, after an overnight fast, 50 grams of lactose (in a solution with water) is swallowed. If the lactose cannot be digested, enteric bacteria metabolize it and produce hydrogen. This, along with methane, can be detected in the patient's breath by a clinical gas chromatograph or a compact solid state detector. The test takes about 2 to 3 hours. A medical condition with similar symptoms is fructose malabsorption.

In conjunction, measuring the blood glucose level every 10 - 15 minutes after ingestion will show a "flat curve" in individuals with lactose malabsorption, while the lactase persistent will have a significant "top", with an elevation of typically 50 to 100% within 1 - 2 hours. However, given the need for frequent blood drawns, this approach has been largely supplanted by breath testing.

Can be used to diagnose lactose intolerance in small infants, for whom other forms of testing are risky or impractical.

An intestinal biopsy can confirm lactose intolerance following discovery of elevated hydrogen in the hydrogen breath test. However, given the invasive nature of this test, and the need for a highly specialized laboratory to measure lactase enzymes or mRNA in the biopsy tissue, this approach is used almost exclusively in clinical research.

The ancient Greek physician Hippocrates (460-370 B.C.) first noted gastrointestinal upset and skin problems in some who consumed milk; patients experiencing the former symptom may likely have been suffering from lactose intolerance. However, it was only in the last few decades that the syndrome was more widely described by modern medical science.

The condition was first recognized in the 1950s and 1960s when various organizations like the United Nations began to engage in systematic famine-relief efforts in countries outside Europe for the first time. Holzel et al. (1959) and Durand (1959) produced two of the earliest studies of lactose intolerance. As anecdotes of embarrassing dairy-induced discomfort increased, the First World donor countries could no longer ascribe the reports to spoilage in transit or inappropriate food preparation by the Third World recipients.

Because the first nations to industrialize and develop modern scientific medicine were dominated by people of European descent, adult dairy consumption was long taken for granted. Westerners for some time did not recognize that the majority of the human ethno-genetic groups could not consume dairy products during adulthood. Although there had been regular contact between Europeans and non-Europeans throughout history, the notion that large-scale medical studies should be representative of the ethnic diversity of the human populations (as well as all genders and ages) did not become well-established until after the American Civil Rights Movement.

Since then, the relationship between lactase and lactose has been thoroughly investigated in food science due to the growing market for dairy products among non-Europeans.

Originally it was hypothesised that gut bacteria such as E. coli produced the lactase enzyme needed to cleave lactose into its constituent monosaccharides and thus become metabolisable and digestible by humans. Some form of human-bacteria symbiosis was proposed as a means of producing lactase in the human digestive tract. Genetics and protein analysis techniques by the early 1970s revealed this to be untrue; humans produce their own lactase enzyme natively in intestine cells.

According to Heyman (2006), approximately 70% of the global population cannot tolerate lactose in adulthood. Thus, some argue that the terminology should be reversed — lactose intolerance should be seen as the norm, and the minority groups should be labeled as having lactase persistence. A counter argument to this is that the cultures that don't generally consume unmodified milk products have little need to discuss their intolerance to it, leaving the cultures for which lactose intolerance is a significant dietary issue to define its terminology.

Lactose intolerance has been studied as an aid in understanding ancient diets and population movement in prehistoric societies. Milking an animal vastly increases the calories that may be extracted from the animal as compared to the consumption of its meat alone. It is not surprising then, that consuming milk products became an important part of the agricultural way of life in the Neolithic. It is believed that most of the milk was used to make mature cheeses which are mostly lactose free.

Roman authors recorded that the people of northern Europe, particularly Britain and Germany drank unprocessed milk (as opposed to the Romans who made cheese). This corresponds very closely with modern European distributions of lactose intolerance, where the people of Britain, Germany and Scandinavia have a good tolerance, and those of southern Europe, especially Italy, have a poorer tolerance.

In east Asia, historical sources also attest that the Chinese did not consume milk, whereas the nomads that lived on the borders did. Again, this reflects modern distributions of intolerance. China is particularly notable as a place of poor tolerance, whereas in Mongolia and the Asian steppes horse milk is drunk regularly. This tolerance is thought to be advantageous as the nomads do not settle down long enough to process mature cheese. Given that their prime source of income is generated through horses, to ignore their milk as a source of calories would be greatly detrimental. The nomads also make an alcoholic beverage, called Kumis, from horse milk, although the fermentation process reduces the amount of lactose present.

The African Fulani have a nomadic origin and their culture once completely revolved around cow, goat, and sheep herding. Dairy products were once a large source of nutrition for them. As might be expected if lactase persistence evolved in response to dairy product consumption, they are particularly tolerant to lactose (about 77% of the population). Many Fulani live in Guinea-Conakry, Burkina Faso, Mali, Nigeria, Niger, Cameroon, and Chad.

There is some debate on exactly where and when genetic mutation(s) occurred. Some argue for separate mutation events in Sweden (which has one of the lowest levels of lactose intolerance in the world) and the Arabian Peninsula around 4000 BC. However, others argue for a single mutation event in the Middle East at about 4500 BC which then subsequently radiated. Some sources suggest a third and more recent mutation in the East African Tutsi. Whatever the precise origin in time and place, most modern Northern Europeans and people of European ancestry show the effects of this mutation (that is, they are able to safely consume milk products all their lives) while most modern East Asians, sub-Saharan Africans and native peoples of the Americas and Pacific Islands do not (making them lactose intolerant as adults). The Maasai ability to consume dairy without exhibiting symptoms may be due to a different genetic mutation. Or it may be due to the fact that they curdle their milk before they consume it, removing the lactose.

A thorough scientific overview of genetic polymorphisms of intestinal lactase activity in adult hypolactasia, is in chapter 76 of OMMBID. A noncoding variation in the MCM6 gene has been strongly associated with adult type hypolactasia.

For persons living in societies where the diet contains relatively little dairy, lactose intolerance is not considered a condition that requires treatment. However, those living among societies that are largely lactose-tolerant may find lactose intolerance troublesome. Although there are still no methodologies to reinstate lactase production, some individuals have reported their intolerance to vary over time (depending on health status and pregnancy). Lactose intolerance is not usually an all-or-nothing condition: the reduction in lactase production, and hence, the amount of lactose that can be tolerated varies from person to person. Since lactose intolerance poses no further threat to a person's health, managing the condition consists of minimizing the occurrence and severity of symptoms. Berdanier and Hargrove recognise 4 general principles: 1) avoidance of dietary lactose; 2) substitution to maintain nutrient intake; 3) regulation of calcium intake; 4) use of enzyme substitute.

Since each individual's tolerance to lactose varies, according to the US National Institute of Health, "Dietary control of lactose intolerance depends on people learning through trial and error how much lactose they can handle." Label reading is essential as commercial terminology varies according to language and region.

Lactose is present in 2 large food categories: Conventional dairy products, and as a food additive (in dairy and non dairy products).

Lactose is a water-soluble molecule. Therefore fat percentage and the curdling process have an impact on which foods may be tolerated. In the curdling process lactose is found in the water portion along with whey and casein, but is not found in the fat portion. Dairy products which are "fat reduced" or "fat free" generally have a slightly higher lactose percentage. Additionally, low fat dairy foods also often have various dairy derivatives such as milk solids added to them to enhance sweetness, increasing the lactose content.

Butter. The butter-making process separates the majority of milk's water components from the fat components. Lactose, being a water soluble molecule, will be present in small quantities in the butter unless it is also fermented to produce cultured butter.

Yogurt and kefir. People can be more tolerant of traditionally made yogurt than milk because it contains lactase enzyme produced by the bacterial cultures used to make the yogurt. However, many commercial brands contain milk solids, increasing the lactose content.

Cheeses. Traditionally made hard cheese (such as Swiss cheese) and soft ripened cheeses may create less reaction than the equivalent amount of milk because of the processes involved. Fermentation and higher fat content contribute to lesser amounts of lactose. Traditionally made Swiss or Cheddar might contain 10% of the lactose found in whole milk. In addition, the traditional aging methods of cheese (over 2 years) reduces their lactose content to practically nothing. Commercial cheese brands, however, are generally manufactured by modern processes that do not have the same lactose reducing properties, and as no regulations mandate what qualifies as an "aged" cheese, this description does not provide any indication of whether the process used significantly reduced lactose.

Sour cream and ice cream, like yogurt, if made the traditional way, may be tolerable, but most modern brands add milk solids. Consult labels.

Examples of lactose levels in foods. As scientific consensus has not been reached concerning lactose percentage analysis methods (non-hydrated form or the mono-hydrated form), and considering that dairy content varies greatly according to labeling practices, geography and manufacturing processes, lactose numbers may not be very reliable. The following are examples of lactose levels in foods which commonly set off symptoms. These quantities are to be treated as guidelines only.

Lactose (also present when labels state lactoserum, whey, milk solids, modified milk ingredients, etc) is a commercial food additive used for its texture, flavor and adhesive qualities, and is found in foods such as processed meats (sausages/hot dogs, sliced meats, Pâtés), gravy stock powder, margarines sliced breads, breakfast cereals, potato chips, dried fruit, processed foods, medications, preprepared meals, meal replacement (powders and bars), protein supplements (powders and bars).

Kosher products labeled pareve are free of milk. However, if a "D" (for "Dairy) is present next to the circled "K", "U", or other hechsher, the food likely contains milk solids (although it may also simply indicate that the product was produced on equipment shared with other products containing milk derivatives).

The dairy industry has created low-lactose or lactose-free products to replace regular dairy. Lactose-free milk can be produced by passing milk over lactase enzyme bound to an inert carrier: once the molecule is cleaved, there are no lactose ill-effects. A form is available with reduced amounts of lactose (typically 30% of normal), and alternatively with nearly 0%. Finland, where approximately 17% of the Finnish-speaking population has hypolactasia, has had "HYLA" (acronym for hydrolysed lactose) products available for many years. These low-lactose level cow's milk products, ranging from ice cream to cheese, use a Valio patented chromatographic separation method to remove lactose. The ultra-pasteurization process, combined with aseptic packaging, ensures a long shelf-life. Recently, the range of low-lactose products available in Finland has been augmented with milk and other dairy products (such as ice cream, butter, and buttermilk) that contain no lactose at all. The remaining about 20% of lactose in HYLA products is taken care of enzymatically. These typically cost slightly more than equivalent products containing lactose. Valio also markets these products in Sweden and in Estonia.

Alternatively, a bacterium such as L. acidophilus may be added, which affects the lactose in milk the same way it affects the lactose in yogurt (see above).

Plant based milks and derivatives are the only ones to be 100% lactose free: soy milk, rice milk, almond milk, hazelnut milk, oat milk, hemp milk, peanut milk, horchata.

When lactose avoidance is not possible, or on occasions when a person chooses to consume such items, then enzymatic lactase supplements may be used.

Lactase enzymes similar to those produced in the small intestines of humans are produced industrially by fungi of the genus aspergillus. The enzyme, β-galactosidase, is available in tablet form in a variety of doses, in many countries without a prescription. It functions well only in high-acid environments, such as that found in the human gut due to the addition of gastric juices from the stomach. Unfortunately, too much acid can denature it, and it therefore should not be taken on an empty stomach. Also, the enzyme is ineffective if it does not reach the small intestine by the time the problematic food does. Lactose-sensitive individuals should experiment with both timing and dosage to fit their particular need. But supplements such as these may not be able to provide the accurate amount of lactase needed to adequately digest the lactose contained in dairy products, which may lead to symptoms similar to the existing lactose intolerance.

While essentially the same process as normal intestinal lactose digestion, direct treatment of milk employs a different variety of industrially produced lactase. This enzyme, produced by yeast from the genus kluyveromyces, takes much longer to act, must be thoroughly mixed throughout the product, and is destroyed by even mildly acidic environments. It therefore has been much less popular as a consumer product (sold, where available, as a liquid) than the aspergillus-produced tablets, despite its predictable effectiveness. Its main use is in producing the lactose-free or lactose-reduced dairy products sold in supermarkets.

Enzymatic lactase supplementation may have an advantage over avoiding dairy products, in that alternative provision does not need to be made to provide sufficient calcium intake, especially in children.

For healthy individuals with secondary lactose intolerance, it may be possible to train bacteria in the large intestine to break down lactose more effectively by consuming small quantities of dairy products several times a day over a couple of weeks. Reintroducing dairy in this way to people who have an underlying or chronic illness, however, is not recommended, as certain illnesses damage the intestinal tract in a way which prevents the lactase enzyme from being expressed.

Some studies indicate that environmental factors (more specifically, the consumption of lactose) may "play a more important role than genetic factors in the etio-pathogenesis of milk intolerance", but some other publications suggest that lactase production does not seem to be induced by dairy/lactose consumption.

Populations where primary lactose intolerance is the norm have demonstrated similar health levels to westerners (outside of malnutrition issues; see the History of genetic prevalence subsection above) or better health (Japan).

While secondary lactose intolerance does not inherently affect an individual's nutritional needs, according to accepted medical doctrines in western European and North American countries, dairy is an essential part of a healthy diet. Dairy products are relatively good and accessible sources of calcium and potassium and many countries mandate that milk be fortified with vitamin A and vitamin D. Consequently, in dairy-consuming societies, dairy is often a main source of these nutrients; and, for lacto-vegetarians, a main source of vitamin B12. Individuals who reduce or eliminate consumption of dairy must obtain these nutrients elsewhere. However, Asian populations for whom dairy is not part of their food culture do not present decreased health and sometimes present above average health, like in Japan.

Plant based milk substitutes are not naturally rich in calcium, potassium, or vitamins A or D (and, like most non-animal products, contain no vitamin B12). However, prominent brands are often voluntarily fortified with many of these nutrients.

An increasing number of calcium-fortified breakfast foods, such as orange juice, bread, and dry cereal have been appearing on supermarket shelves. Many fruits and vegetables are rich in potassium and vitamin A; animal products like meat and eggs are rich in vitamin B12, and the human body itself produces some vitamin D from exposure to direct sunlight. Finally, a dietitian or physician may recommend a vitamin or mineral supplement to make up for any remaining nutritional shortfall.

Lactose-reduced dairy products have the same nutritional content as their full-lactose counterparts, but their taste and appearance may differ slightly.

Most infants with gastroenteritis due to rotavirus do not develop lactose intolerance, so these infants do not benefit from being put on a lactose-free diet unless symptoms of lactose intolerance are severe and persistent.

Congenital lactase deficiency, or CLD, is an autosomal recessive disorder which prevents the expression of lactase. Before the 20th century, infants with this disease rarely survived. As substitute and lactose-free infant formulas later became available, nursing infants affected with CLD could now have their normal nutritional needs met. Beyond infancy, individuals with CLD usually have the same nutritional concerns as those affected by secondary lactose intolerance.

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Milk allergy


Milk allergy is a food allergy immune adverse reaction to one or more of the proteins in cow's milk.

The principal symptoms are gastrointestinal, dermatological and respiratory. These can translate to: skin rash, hives, vomiting, diarrhea, constipation and distress. The clinical spectrum extends to diverse disorders: anaphylactic reactions, atopic dermatitis, wheeze, infantile colic, gastroesophageal reflux (GER), oesophagitis, allergic colitis and constipation.

The symptoms may occur within a few minutes after exposure in immediate reactions, or after hours (and in some cases after several days) in delayed reactions.

Milk allergy is a food allergy, an adverse immune reaction to a food protein that is normally harmless to the non-allergic individual. Lactose intolerance is a non-allergic food sensitivity, and comes from a lack of production of the enzyme lactase, required to digest the predominant sugar in milk. Lactose intolerance is not actually a disease or malady. Adverse effects of lactose intolerance occur at much higher milk consumption than adverse effects of milk allergy.

Milk protein intolerance (MPI) is delayed reaction to a food protein that is normally harmless to the non-allergic, non-intolerant individual. Milk protein intolerance produces a non-IgE antibody and is not detected by allergy blood tests. Milk protein intolerance produces a range of symptoms very similar to milk allergy symptoms, but can also include blood and/or mucus in the stool. Treatment for milk protein intolerance is the same as for milk allergy. Milk protein intolerance is also referred to as milk soy protein intolerance (MSPI).

Currently the only treatment for milk allergies is total avoidance of milk proteins. Products in addition to milk itself to be avoided by those with milk allergy include yogurt, butter, cheese, and cream. Goats' milk products may also need to be avoided.

Ingredients that also denote that food product contains dairy milk include whey, casein, caseinate, butter flavor, lactic acid (lactic acid derived from dairy products), natural or artificial flavors such as milk or butter flavor, and sodium caseinate.

Also, many processed foods that do not contain milk may be processed on equipment contaminated with dairy foods, which may cause an allergic reaction in some sensitive individuals.

Since milk protein may be transferred from a breastfeeding mother to an allergic infant, lactating mothers are given an elimination diet. For formula fed infants, milk substitute formulas are used to provide the infant with a complete source of nutrition. Milk substitutes include soy based formula, hypoallergenic formulas based on partially or extensively hydrolyzed protein (such as nutramigen, alimentum, and pregestemil) or free amino acids (such as neocate). Partially hydrolysates formula are characterised by a larger proportion of long chains (peptides) and are considered more palatable. However, they are intended for prophylactic use and are not considered suitable for treatment of milk allergy/intolerance. Extensively hydrolysed proteins comprise predominantly of free amino acids and short peptides. Casein and whey are the most commonly used sources of protein for hydrolysates because of their high nutritional quality and their amino acid composition. Non-milk derived amino acid-based formulas are suitable for the treatment of both mild-moderate and severe milk allergy, if allergic infants don’t respond to protein hydrolysate formulas. Soy based formula does have a risk of allergic sensitivity, as some infants who are allergic to milk may also be allergic to soy.

There are many commercially available replacements for milk for children and adults - Rice milk, soy milk, oat milk and almond milk are also sometimes used as milk substitutes, but are not suitable nutrition for infants. Fruit juices supplemented with calcium which may provide an alternative for adults and children. If on an avoidance diet, it is important that dietary advice is taken as a replacement source of calcium may need to be found to prevent the longer term risk of calcium deficiency and osteoporosis.

Accidental Exposure Treatment for accidental ingestion of milk products by allergic individuals varies depending on the sensitivity of the allergic person. Frequently medications such as an Epinephrine pen or an Antihistamine such as Diphenhydramine (Benadryl) are prescribed by an allergist in case of accidental ingestion. Milk allergy can cause anaphylaxis, a severe, life threatening allergic reaction.

Like many food allergies milk allergy may be outgrown eventually by children, although a percentage of children do not outgrow their allergy.(see below) Milk allergy is more likely to be outgrown than peanut allergy.

Milk allergy is the most common food allergy in early childhood. It affects somewhere between 2% and 3% of infants in developed countries, but approximately 85-90% of affected children lose clinical reactivity to milk once they surpass 3 years of age.

Between 13% and 20% of children allergic to milk are also allergic to beef.

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A platter filled with various types of cheese

Cheese is a food consisting of proteins and fat from milk, usually the milk of cows, buffalo, goats, or sheep. It is produced by coagulation of the milk protein casein. Typically, the milk is acidified and addition of the enzyme rennet causes coagulation. The solids are then separated and pressed into final form. Some cheeses also contain molds, either on the outer rind or throughout.

Hundreds of types of cheese are produced. Their different styles, textures and flavors depend on the origin of the milk (including the animal's diet), whether it has been pasteurized, butterfat content, the species of bacteria and mold, and the processing including the length of aging. Herbs, spices, or wood smoke may be used as flavoring agents. The yellow to red color of many cheeses is a result of adding annatto. Cheeses are eaten both on their own and cooked in various dishes; most cheeses melt when heated.

For a few cheeses, the milk is curdled by adding acids such as vinegar or lemon juice. Most cheeses are acidified to a lesser degree by bacteria, which turn milk sugars into lactic acid, then the addition of rennet completes the curdling. Vegetarian alternatives to rennet are available; most are produced by fermentation of the fungus Mucor miehei, but others have been extracted from various species of the Cynara thistle family.

Cheese has served as a hedge against famine and is a good travel food. It is valuable for its portability, long life, and high content of fat, protein, calcium, and phosphorus. Cheese is more compact and has a longer shelf life than the milk from which it is made. Cheesemakers near a dairy region may benefit from fresher, lower-priced milk, and lower shipping costs. The long storage life of cheese allows selling it when markets are more favorable.

The origin of the word cheese appears to be the Latin caseus, from which the modern word casein is closely derived. The earliest source is probably from the proto-Indo-European root *kwat-, which means "to ferment, become sour".

In the English language, the modern word cheese comes from chese (in Middle English) and cīese or cēse (in Old English). Similar words are shared by other West Germanic languages — West Frisian tsiis, Dutch kaas, German Käse, Old High German chāsi — all of which probably come from the reconstructed West-Germanic root *kasjus, which in turn is an early borrowing from Latin.

The Latin word caseus is also the source from which are derived the Spanish queso, Portuguese queijo, Malay/Indonesian Language keju (a borrowing from the Portuguese word queijo), Romanian caş and Italian cacio.

The Celtic root which gives the Irish cáis and the Welsh caws are also related.

When the Romans began to make hard cheeses for their legionaries' supplies, a new word started to be used: formaticum, from caseus formatus, or "molded cheese" (as in "formed", not "molded"). It is from this word that we get the French fromage, Italian formaggio, Catalan formatge, Breton fourmaj and Provençal furmo. Cheese itself is occasionally employed in a sense that means "molded" or "formed". Head cheese uses the word in this sense.

Cheese is an ancient food whose origins predate recorded history. There is no conclusive evidence indicating where cheesemaking originated, either in Europe, Central Asia or the Middle East, but the practice had spread within Europe prior to Roman times and, according to Pliny the Elder, had become a sophisticated enterprise by the time the Roman Empire came into being.

Proposed dates for the origin of cheesemaking range from around 8000 BCE (when sheep were first domesticated) to around 3000 BCE. The first cheese may have been made by people in the Middle East or by nomadic Turkic tribes in Central Asia. Since animal skins and inflated internal organs have, since ancient times, provided storage vessels for a range of foodstuffs, it is probable that the process of cheese making was discovered accidentally by storing milk in a container made from the stomach of an animal, resulting in the milk being turned to curd and whey by the rennet from the stomach. There is a widely told legend about the discovery of cheese by an Arab trader who used this method of storing milk. The legend has many individual variations.

Cheesemaking may also have begun independent of this by the pressing and salting of curdled milk in order to preserve it. Observation that the effect of making milk in an animal stomach gave more solid and better-textured curds, may have led to the deliberate addition of rennet.

The earliest archeological evidence of cheesemaking has been found in Egyptian tomb murals, dating to about 2000 BCE. The earliest cheeses were likely to have been quite sour and salty, similar in texture to rustic cottage cheese or feta, a crumbly, flavorful Greek cheese.

Cheese produced in Europe, where climates are cooler than the Middle East, required less salt for preservation. With less salt and acidity, the cheese became a suitable environment for beneficial microbes and molds, giving aged cheeses their pronounced and interesting flavors.

When he had so done he sat down and milked his ewes and goats, all in due course, and then let each of them have her own young. He curdled half the milk and set it aside in wicker strainers.

By Roman times, cheese was an everyday food and cheesemaking a mature art, not very different from what it is today. Columella's De Re Rustica (circa 65 CE) details a cheesemaking process involving rennet coagulation, pressing of the curd, salting, and aging. Pliny's Natural History (77 CE) devotes a chapter (XI, 97) to describing the diversity of cheeses enjoyed by Romans of the early Empire. He stated that the best cheeses came from the villages near Nîmes, but did not keep long and had to be eaten fresh. Cheeses of the Alps and Apennines were as remarkable for their variety then as now. A Ligurian cheese was noted for being made mostly from sheep's milk, and some cheeses produced nearby were stated to weigh as much as a thousand pounds each. Goats' milk cheese was a recent taste in Rome, improved over the "medicinal taste" of Gaul's similar cheeses by smoking. Of cheeses from overseas, Pliny preferred those of Bithynia in Asia Minor.

Rome spread a uniform set of cheesemaking techniques throughout much of Europe, and introduced cheesemaking to areas without a previous history of it. As Rome declined and long-distance trade collapsed, cheese in Europe diversified further, with various locales developing their own distinctive cheesemaking traditions and products. The British Cheese Board claims that Britain has approximately 700 distinct local cheeses; France and Italy have perhaps 400 each. (A French proverb holds there is a different French cheese for every day of the year, and Charles de Gaulle once asked "how can you govern a country in which there are 246 kinds of cheese?") Still, the advancement of the cheese art in Europe was slow during the centuries after Rome's fall. Many of the cheeses we know best today were first recorded in the late Middle Ages or after— cheeses like Cheddar around 1500 CE, Parmesan in 1597, Gouda in 1697, and Camembert in 1791.

In 1546, John Heywood wrote in The Proverbs of John Heywood that "the moon is made of a greene cheese." (Greene may refer here not to the color, as many now think, but to being new or unaged.) Variations on this sentiment were long repeated. Although some people assumed that this was a serious belief in the era before space exploration, it is more likely that Heywood was indulging in nonsense.

Until its modern spread along with European culture, cheese was nearly unheard of in oriental cultures, in the pre-Columbian Americas, and of only limited use in sub-Mediterranean Africa, mainly being widespread and popular only in Europe and areas influenced strongly by its cultures. But with the spread, first of European imperialism, and later of Euro-American culture and food, cheese has gradually become known and increasingly popular worldwide, though still rarely considered a part of local ethnic cuisines outside Europe, the Middle East, and the Americas.

The first factory for the industrial production of cheese opened in Switzerland in 1815, but it was in the United States where large-scale production first found real success. Credit usually goes to Jesse Williams, a dairy farmer from Rome, New York, who in 1851 started making cheese in an assembly-line fashion using the milk from neighboring farms. Within decades hundreds of such dairy associations existed.

The 1860s saw the beginnings of mass-produced rennet, and by the turn of the century scientists were producing pure microbial cultures. Before then, bacteria in cheesemaking had come from the environment or from recycling an earlier batch's whey; the pure cultures meant a more standardized cheese could be produced.

Factory-made cheese overtook traditional cheesemaking in the World War II era, and factories have been the source of most cheese in America and Europe ever since. Today, Americans buy more processed cheese than "real", factory-made or not.

The only strictly required step in making any sort of cheese is separating the milk into solid curds and liquid whey. Usually this is done by acidifying (souring) the milk and adding rennet. The acidification is accomplished directly by the addition of an acid like vinegar in a few cases (paneer, queso fresco), but usually starter bacteria are employed instead. These starter bacteria convert milk sugars into lactic acid. The same bacteria (and the enzymes they produce) also play a large role in the eventual flavor of aged cheeses. Most cheeses are made with starter bacteria from the Lactococci, Lactobacilli, or Streptococci families. Swiss starter cultures also include Propionibacter shermani, which produces carbon dioxide gas bubbles during aging, giving Swiss cheese or Emmental its holes.

Some fresh cheeses are curdled only by acidity, but most cheeses also use rennet. Rennet sets the cheese into a strong and rubbery gel compared to the fragile curds produced by acidic coagulation alone. It also allows curdling at a lower acidity—important because flavor-making bacteria are inhibited in high-acidity environments. In general, softer, smaller, fresher cheeses are curdled with a greater proportion of acid to rennet than harder, larger, longer-aged varieties.

At this point, the cheese has set into a very moist gel. Some soft cheeses are now essentially complete: they are drained, salted, and packaged. For most of the rest, the curd is cut into small cubes. This allows water to drain from the individual pieces of curd.

Some hard cheeses are then heated to temperatures in the range of 35 °C–55 °C (100 °F–130 °F). This forces more whey from the cut curd. It also changes the taste of the finished cheese, affecting both the bacterial culture and the milk chemistry. Cheeses that are heated to the higher temperatures are usually made with thermophilic starter bacteria which survive this step—either lactobacilli or streptococci.

Salt has a number of roles in cheese besides adding a salty flavor. It preserves cheese from spoiling, draws moisture from the curd, and firms up a cheese’s texture in an interaction with its proteins. Some cheeses are salted from the outside with dry salt or brine washes. Most cheeses have the salt mixed directly into the curds.

Most cheeses achieve their final shape when the curds are pressed into a mold or form. The harder the cheese, the more pressure is applied. The pressure drives out moisture—the molds are designed to allow water to escape—and unifies the curds into a single solid body.

A newborn cheese is usually salty yet bland in flavor and, for harder varieties, rubbery in texture. These qualities are sometimes enjoyed—cheese curds are eaten on their own—but normally cheeses are left to rest under carefully controlled conditions. This aging period (also called ripening, or, from the French, affinage) can last from a few days to several years. As a cheese ages, microbes and enzymes transform its texture and intensify its flavor. This transformation is largely a result of the breakdown of casein proteins and milkfat into a complex mix of amino acids, amines, and fatty acids.

Some cheeses have additional bacteria or molds intentionally introduced to them before or during aging. In traditional cheesemaking, these microbes might be already present in the air of the aging room; they are simply allowed to settle and grow on the stored cheeses. More often today, prepared cultures are used, giving more consistent results and putting fewer constraints on the environment where the cheese ages. These cheeses include soft ripened cheeses such as Brie and Camembert, blue cheeses such as Roquefort, Stilton, Gorgonzola, and rind-washed cheeses such as Limburger.

No one categorization scheme can capture all the diversity of the world's cheeses. In practice, no single system is employed and different factors are emphasised in describing different classes of cheeses. This typical list of cheeses includes categories from foodwriter Barbara Ensrud.

The main factor in the categorization of these cheese is their age. Fresh cheeses without additional preservatives can spoil in a matter of days.

For these simplest cheeses, milk is curdled and drained, with little other processing. Examples include cottage cheese, Romanian Caş, Neufchâtel (the model for American-style cream cheese), and fresh goat's milk chèvre. Such cheeses are soft and spreadable, with a mild taste.

Whey cheeses are fresh cheeses made from the whey discarded while producing other cheeses. Provencal Brousse, Corsican Brocciu, Italian Ricotta, Romanian Urda, Greek Mizithra, and Norwegian Geitost are examples. Brocciu is mostly eaten fresh, and is as such a major ingredient in Corsican cuisine, but it can be aged too.

Traditional pasta filata cheeses such as Mozzarella also fall into the fresh cheese category. Fresh curds are stretched and kneaded in hot water to form a ball of Mozzarella, which in southern Italy is usually eaten within a few hours of being made. Stored in brine, it can be shipped, and is known worldwide for its use on pizzas. Other firm fresh cheeses include paneer and queso fresco.

Categorizing cheeses by firmness is a common but inexact practice. The lines between "soft", "semi-soft", "semi-hard", and "hard" are arbitrary, and many types of cheese are made in softer or firmer variations. The factor controlling the hardness of a cheese is its moisture content which is dependent on the pressure with which it is packed into molds and the length of time it is aged.

Semi-soft cheeses and the sub-group, Monastery cheeses have a high moisture content and tend to be bland in flavor. Some well-known varieties include Havarti, Munster and Port Salut.

Cheeses that range in texture from semi-soft to firm include Swiss-style cheeses like Emmental and Gruyère. The same bacteria that give such cheeses their holes also contribute to their aromatic and sharp flavors. Other semi-soft to firm cheeses include Gouda, Edam, Jarlsberg and Cantal. Cheeses of this type are ideal for melting and are used on toast for quick snacks.

Harder cheeses have a lower moisture content than softer cheeses. They are generally packed into molds under more pressure and aged for a longer time. Cheeses that are semi-hard to hard include the familiar Cheddar, originating in the village of Cheddar in England but now used as a generic term for this style of cheese, of which varieties are imitated worldwide and are marketed by strength or the length of time they have been aged. Cheddar is one of a family of semi-hard or hard cheeses (including Cheshire and Gloucester) whose curd is cut, gently heated, piled, and stirred before being pressed into forms. Colby and Monterey Jack are similar but milder cheeses; their curd is rinsed before it is pressed, washing away some acidity and calcium. A similar curd-washing takes place when making the Dutch cheeses Edam and Gouda.

Hard cheeses — "grating cheeses" such as Parmesan and Pecorino Romano—are quite firmly packed into large forms and aged for months or years.

Some cheeses are categorized by the source of the milk used to produce them or by the added fat content of the milk from which they are produced. While most of the world's commercially available cheese is made from cows' milk, many parts of the world also produce cheese from goats and sheep, well-known examples being Roquefort, produced in France, and Pecorino Romano, produced in Italy, from ewes's milk. One farm in Sweden also produces cheese from moose's milk. Sometimes cheeses of a similar style may be available made from milk of different sources, Feta style cheeses, for example, being made from goats' milk in Greece and of sheep and cows milk elsewhere.

Double cream cheeses are soft cheeses of cows' milk which are enriched with cream so that their fat content is 60% or, in the case of triple creams, 75%.

There are three main categories of cheese in which the presence of mold is a significant feature: soft ripened cheeses, washed rind cheeses and blue cheeses.

Soft-ripened cheeses are those which begin firm and rather chalky in texture but are aged from the exterior inwards by exposing them to mold. The mold may be a velvety bloom of Penicillium candida or P. camemberti that forms a flexible white crust and contributes to the smooth, runny, or gooey textures and more intense flavors of these aged cheeses. Brie and Camembert, the most famous of these cheeses, are made by allowing white mold to grow on the outside of a soft cheese for a few days or weeks. Goats' milk cheeses are often treated in a similar manner, sometimes with white molds (Chèvre-Boîte) and sometimes with blue.

Washed-rind cheeses are soft in character and ripen inwards like those with white molds; however, they are treated differently. Washed rind cheeses are periodically cured in a solution of saltwater brine and other mold-bearing agents which may include beer, wine, brandy and spices, making their surfaces amenable to a class of bacteria Brevibacterium linens (the reddish-orange "smear bacteria") which impart pungent odors and distinctive flavors. Washed-rind cheeses can be soft (Limburger), semi-hard (Munster), or hard (Appenzeller). The same bacteria can also have some impact on cheeses that are simply ripened in humid conditions, like Camembert.

So-called blue cheese is created by inoculating a cheese with Penicillium roqueforti or Penicillium glaucum. This is done while the cheese is still in the form of loosely pressed curds, and may be further enhanced by piercing a ripening block of cheese with skewers in an atmosphere in which the mold is prevalent. The mold grows within the cheese as it ages. These cheeses have distinct blue veins which gives them their name, and, often, assertive flavors. The molds may range from pale green to dark blue, and may be accompanied by white and crusty brown molds.Their texture can be soft or firm. Some of the most renowned cheeses are of this type, each with its own distinctive color, flavor, texture and smell. They include Roquefort, Gorgonzola, and Stilton.

Processed cheese is made from traditional cheese and emulsifying salts, often with the addition of milk, more salt, preservatives, and food coloring. It is inexpensive, consistent, and melts smoothly. It is sold packaged and either pre-sliced or unsliced, in a number of varieties. It is also available in spraycans.

At refrigerator temperatures, the fat in a piece of cheese is as hard as unsoftened butter, and its protein structure is stiff as well. Flavor and odor compounds are less easily liberated when cold. For improvements in flavor and texture, it is widely advised that cheeses be allowed to warm up to room temperature before eating. If the cheese is further warmed, to 26–32 °C (80–90 °F), the fats will begin to "sweat out" as they go beyond soft to fully liquid.

At higher temperatures, most cheeses melt. Rennet-curdled cheeses have a gel-like protein matrix that is broken down by heat. When enough protein bonds are broken, the cheese itself turns from a solid to a viscous liquid. Soft, high-moisture cheeses will melt at around 55 °C (131 °F), while hard, low-moisture cheeses such as Parmesan remain solid until they reach about 82 °C (180 °F). Acid-set cheeses, including halloumi, paneer, some whey cheeses and many varieties of fresh goat cheese, have a protein structure that remains intact at high temperatures. When cooked, these cheeses just get firmer as water evaporates.

Some cheeses, like raclette, melt smoothly; many tend to become stringy or suffer from a separation of their fats. Many of these can be coaxed into melting smoothly in the presence of acids or starch. Fondue, with wine providing the acidity, is a good example of a smoothly melted cheese dish. Elastic stringiness is a quality that is sometimes enjoyed, in dishes including pizza and Welsh rarebit. Even a melted cheese eventually turns solid again, after enough moisture is cooked off. The saying "you can't melt cheese twice" (meaning "some things can only be done once") refers to the fact that oils leach out during the first melting and are gone, leaving the non-meltable solids behind.

As its temperature continues to rise, cheese will brown and eventually burn. Browned, partially burned cheese has a particular distinct flavor of its own and is frequently used in cooking (e.g., sprinkling atop items before baking them).

In general, cheese supplies a great deal of calcium, protein, and phosphorus. A 30-gram (1.1 oz) serving of Cheddar cheese contains about 7 grams (0.25 oz) of protein and 200 milligrams of calcium. Nutritionally, cheese is essentially concentrated milk: it takes about 200 grams (7.1 oz) of milk to provide that much protein, and 150 grams (5.3 oz) to equal the calcium.

Cheese potentially shares other of milk's nutritional content as well. The Center for Science in the Public Interest describes cheese as America's number one source of saturated fat, adding that the average American ate 30 lb (14 kg) of cheese in the year 2000, up from 11 lb (5 kg) in 1970. Their recommendation is to limit full-fat cheese consumption to 2 oz (57 g) a week. Whether cheese's highly saturated fat actually leads to an increased risk of heart disease is called into question when considering France and Greece, which lead the world in cheese eating (more than 14 oz/400 g a week per person, or over 45 lb/20 kg a year) yet have relatively low rates of heart disease. This seeming discrepancy is called the French Paradox; the higher rates of consumption of red wine in these countries is often invoked as at least a partial explanation.

A study by the British Cheese Board in 2005 to determine the effect of cheese upon sleep and dreaming discovered that, contrary to the idea that cheese commonly causes nightmares, the effect of cheese upon sleep was positive. The majority of the two hundred people tested over a fortnight claimed beneficial results from consuming cheeses before going to bed, the cheese promoting good sleep. Six cheeses were tested and the findings were that the dreams produced were specific to the type of cheese. Although the apparent effects were in some cases described as colorful and vivid, or cryptic, none of the cheeses tested were found to induce nightmares. However, the six cheeses were all British. The results might be entirely different if a wider range of cheeses were tested. Cheese contains tryptophan, an amino acid that has been found to relieve stress and induce sleep.

Like other dairy products, cheese contains casein, a substance that when digested by humans breaks down into several chemicals, including casomorphine, an opioid peptide. In the early 1990s it was hypothesized that autism can be caused or aggravated by opioid peptides. Based on this hypothesis, diets that eliminate cheese and other dairy products are widely promoted. Studies supporting these claims have had significant flaws, so the data are inadequate to guide autism treatment recommendations.

Cheese is often avoided by those who are lactose intolerant, but ripened cheeses like Cheddar contain only about 5% of the lactose found in whole milk, and aged cheeses contain almost none. Nevertheless, people with severe lactose intolerance should avoid eating dairy cheese. As a natural product, the same kind of cheese may contain different amounts of lactose on different occasions, causing unexpected painful reactions. As an alternative, also for vegans, there is already a wide range of different soy cheese kinds available. Some people suffer reactions to amines found in cheese, particularly histamine and tyramine. Some aged cheeses contain significant concentrations of these amines, which can trigger symptoms mimicking an allergic reaction: headaches, rashes, and blood pressure elevations.

A number of food safety agencies around the world have warned of the risks of raw-milk cheeses. The U.S. Food and Drug Administration states that soft raw-milk cheeses can cause "serious infectious diseases including listeriosis, brucellosis, salmonellosis and tuberculosis". It is U.S. law since 1944 that all raw-milk cheeses (including imports since 1951) must be aged at least 60 days. Australia has a wide ban on raw-milk cheeses as well, though in recent years exceptions have been made for Swiss Gruyère, Emmental and Sbrinz, and for French Roquefort. There is a trend for cheeses to be pasteurized even when not required by law.

Compulsory pasteurization is controversial. Pasteurization does change the flavor of cheeses, and unpasteurized cheeses are often considered to have better flavor, so there are reasons not to routinely pasteurize all cheeses. Some say that health concerns are overstated, pointing out that pasteurization of the milk used to make cheese does not ensure its safety in any case. This is supported by statistics showing that in some European countries where young raw-milk cheeses may legally be sold, most cheese-related food poisoning incidents were traced to pasteurized cheeses.

Pregnant women may face an additional risk from cheese; the U.S. Centers for Disease Control has warned pregnant women against eating soft-ripened cheeses and blue-veined cheeses, due to the listeria risk, which can cause miscarriage or harm to the fetus during birth.

Worldwide, cheese is a major agricultural product. According to the Food and Agricultural Organization of the United Nations, over 18 million metric tons of cheese were produced worldwide in 2004. This is more than the yearly production of coffee beans, tea leaves, cocoa beans and tobacco combined. The largest producer of cheese is the United States, accounting for 30% of world production, followed by Germany and France.

The biggest exporter of cheese, by monetary value, is France; the second, Germany (although it is first by quantity). Among the top ten exporters, only Ireland, New Zealand, the Netherlands and Australia have a cheese production that is mainly export oriented: respectively 95%, 90%, 72%, and 65% of their cheese production is exported. Only 30% of French production, the world's largest exporter, is exported. The United States, the biggest world producer of cheese, is a marginal exporter, as most of its production is for the domestic market.

Germany is the largest importer of cheese. The UK and Italy are the second- and third-largest importers.

Greece is the world's largest (per capita) consumer of cheese, with 27.3 kg eaten by the average Greek. (Feta accounts for three-quarters of this consumption.) France is the second biggest consumer of cheese, with 24 kg by inhabitant. Emmental (used mainly as a cooking ingredient) and Camembert are the most common cheeses in France Italy is the third biggest consumer by person with 22.9 kg. In the U.S., the consumption of cheese is quickly increasing and has nearly tripled between 1970 and 2003. The consumption per person has reached, in 2003, 14.1 kg (31 pounds). Mozzarella is America's favorite cheese and accounts for nearly a third of its consumption, mainly because it is one of the main ingredients of pizza.

Although cheese is a vital source of nutrition in many regions of the world, and is extensively consumed in others, its use as a nutritional product is not universal. Cheese is rarely found in East Asian dishes, as lactose intolerance is relatively common in that part of the world and hence dairy products are rare. However, East Asian sentiment against cheese is not universal; cheese made from yaks' (chhurpi) or mares' milk is common on the Asian steppes; the national dish of Bhutan, ema datsi, is made from homemade cheese and hot peppers and cheese such as Rushan and Rubing in Yunnan, China is produced by several ethnic minority groups by either using goat's milk in the case of rubing or cow's milk in the case of rushan. Cheese consumption is increasing in China, with annual sales more than doubling from 1996 to 2003 (to a still small 30 million U.S. dollars a year). Certain kinds of Chinese preserved bean curd are sometimes misleadingly referred to in English as "Chinese cheese", because of their texture and strong flavor.

Strict followers of the dietary laws of Islam and Judaism must avoid cheeses made with rennet from animals not slaughtered in a manner adhering to halal or kosher laws. Both faiths allow cheese made with vegetable-based rennet or with rennet made from animals that were processed in a halal or kosher manner. Many less-orthodox Jews also believe that rennet undergoes enough processing to change its nature entirely, and do not consider it to ever violate kosher law. (See Cheese and kashrut.) As cheese is a dairy food under kosher rules it cannot be eaten in the same meal with any meat.

Some vegetarians avoid any cheese made from animal-based rennet. Most widely available vegetarian cheeses are made using rennet produced by fermentation of the fungus Mucor miehei. Vegans and other dairy-avoiding vegetarians do not eat real cheese at all, but some vegetable-based cheese substitutes (usually soy-and almond-based) are available.

Collecting cheese labels is called "tyrosemiophilia".

In modern English slang, something "cheesy" is kitsch, cheap, inauthentic, or of poor quality. The use of the word probably derived not from the word cheese, but from the Persian or Hindi word chiz, meaning a thing. The word was picked up by British soldiers in Asia minor and came to mean "showy" in English slang from which it came to its modern usage.

A more whimsical bit of American and Canadian slang refers to school buses as "cheese wagons", a reference to school bus yellow. Subjects of photographs are often encouraged to "say cheese!", as the word "cheese" contains the phoneme /i/, a long vowel which requires the lips to be stretched in the appearance of a smile. People from Wisconsin and the Netherlands, both centers of cheese production, have been called cheeseheads. This nickname has been embraced by Wisconsin sports fans – especially fans of the Green Bay Packers or Wisconsin Badgers – who are often seen in the stands sporting plastic or foam hats in the shape of giant cheese wedges.

One can also be "cheesed off" – unhappy or annoyed. A leading authority figure may sometimes be referred to as "the head cheese." Also "Cheese it" is a 1950s slang term that means "get away fast". In Australia, children often refer to their mother as 'the Old Cheese'.

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Fructose malabsorption

Fructose malabsorption, formerly inappropriately named "dietary fructose intolerance", is a digestive disorder of the small intestine in which the fructose carrier in enterocytes is deficient. This problem results in the concentration of fructose in the entire intestine to be increased. Fructose malabsorption is found in approximately 30-40% of the population of Central Europe, with about half of the affected individuals exhibiting symptoms.

Fructose Malabsorption is not to be confused with Hereditary Fructose Intolerance (HFI), a condition in which the liver enzymes that break up fructose are deficient.

Medical tests are similar as in lactose intolerance, requiring a hydrogen breath test for a clinical diagnosis. When breath test cannot be done from some reason, reducing substances in the stool, and subsequently fructose in the stool can be checked.

It can be associated with reduced plasma tryptophan and clinical depression.

Fructose is absorbed in the small intestine without help of digestive enzymes. However, even in healthy people, only about 25-50 g of fructose per sitting can be absorbed. Persons with fructose malabsorption may absorb less then 25 g per sitting (amount is arbitrary determined according to investigation of fructose absorption is many individuals).In the large intestine the unabsorbed fructose osmotically reduces the absorption of water and is metabolized by normal colonic bacteria to short chain fatty acids and the gases hydrogen, carbon dioxide and methane. The abnormal increase in hydrogen is detected with the hydrogen breath test.

The physiological consequences of fructose malabsorption include increasing osmotic load, providing substrate for rapid bacterial fermentation, changing gastrointestinal motility, promoting mucosal biofilm and altering the profile of bacteria. These effects are additive with other short-chain poorly absorbed carbohydrates such as sorbitol. The clinical significance of these events depends upon the response of the bowel to such changes; they have a higher chance of inducing symptoms in patients with functional gut disorders than asymptomatic subjects. Some effects of fructose malabsorption are decreased tryptophan, folic acid and zinc in the blood. Restricting dietary intake of free fructose and/or fructans may have durable symptomatic benefits in a high proportion of patients with functional gut disorders, but high quality evidence is lacking.

There is no known cure, but an appropriate diet will help.

Depending upon the sufferer's sensitivity to fructose, small amounts of problem foods could be eaten (especially when they are not the main ingredient of a meal).

Foods with a high glucose content actually help sufferers absorb fructose.

This condition is common in patients with symptoms of Irritable Bowel Syndrome and most patients with fructose malabsorption fit the profile of those with Irritable Bowel Syndrome. A small proportion of patients with both fructose malabsorption and lactose intolerance also suffer from celiac disease.

There is a lot of misinformation and misconception about fruit sugar content. A common belief is that fruits contain mainly, or only, fructose sugar. The USDA food database reveals that many common fruits contain nearly equal amounts of the fructose and glucose. There is a tendency within plants to keep these sugars 50/50. Some aberrantly high fructose fruits are apple, pear, and watermelon, which have over twice as much fructose as glucose. Fructose levels in grapes varies with ripeness and variety, with unripe grapes containing more glucose.

The role that fructans play in fructose malabsorption is still under investigation. However, it is recommended that fructan intake for fructose malabsorber should be kept to less than 0.5 grams/serving and supplements with inulin and fructooligosaccharide (FOS), fructans, intake should be avoided.

Dietary guidelines have been developed for managing fructose malabsorption particularly for individuals with IBS.

Producers of processed food are not currently required by law to mark foods containing "fructose in excess of glucose." This can cause some surprises and pitfalls for fructose malabsorbers.

Note that foods (such as bread) marked "gluten-free" are usually suitable for fructose malabsorbers, though sufferers need to be careful of gluten-free foods that contain dried fruit or high fructose corn syrup or fructose itself in sugar form. However, fructose malabsorbers do not need to avoid gluten as do those with celiac disease.

Many fructose malabsorbers can eat breads made from rye and corn flour. However, these may contain wheat unless marked "wheat-free" (or "gluten-free")(Note, rye bread is NOT gluten-free). Although often assumed to be an acceptable alternative to wheat, spelt flour is not suitable for sufferers of fructose malabsorption, just as it is not appropriate for those with wheat-allergies or celiac disease (while bread made from spelt sprouts may be tolerated by the latter). However, some fructose malabsorbers do not have difficulty with fructans from wheat products while they may have problems with foods that contain excess free fructose.

Note that there are many breads on the market that advertise themselves with phrases like: "No High Fructose Corn Syrup". Many bakeries now produce special breads with a high-inulin content, where inulin is a replacement in the baking process for all three: high fructose corn syrup, flour, and fat. Because of the caloric reduction, lower fat content, dramatic fiber increase, and prebiotic tendencies of the replacement inulin, these breads are considered a healthier alternative to traditionally prepared leavening breads. Inulin breads may even highlight the absence of high fructose corn syrup in the bread. However significant these health advances may be, sufferers of fructose malabsorption will likely find no difference between these new breads and traditionally prepared breads in the areas of flatulence or stool, because inulin is a fructan.

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Coeliac disease

Endoscopic still of duodenum of patient with coeliac disease showing scalloping of folds.

Cœliac disease (pronounced /ˈsiːli.æk/), also spelled celiac disease, is an autoimmune disorder of the small intestine that occurs in genetically predisposed people of all ages from middle infancy on up. Symptoms include chronic diarrhœa, failure to thrive (in children), and fatigue, but these may be absent and symptoms in all other organ systems have been described. A growing portion of diagnoses are being made in asymptomatic persons as a result of increased screening.

Coeliac disease is caused by a reaction to gliadin, a gluten protein found in wheat (and similar proteins of the tribe Triticeae which includes other cultivars such as barley and rye). Upon exposure to gliadin, the enzyme tissue transglutaminase modifies the protein, and the immune system cross-reacts with the small bowel tissue, causing an inflammatory reaction. That leads to flattening of the lining of the small intestine (called villous atrophy). This interferes with the absorption of nutrients because the intestinal villi are responsible for absorption. The only effective treatment is a lifelong gluten-free diet. While the disease is caused by a reaction to wheat proteins, it is not the same as wheat allergy.

This condition has several other names, including: cœliac disease (with "œ" ligature), c(o)eliac sprue, non-tropical sprue, endemic sprue, gluten enteropathy or gluten-sensitive enteropathy, and gluten intolerance. The term coeliac derives from the Greek κοιλιακός (koiliakόs, abdominal), and was introduced in the 19th century in a translation of what is generally regarded as an ancient Greek description of the disease by Aretaeus of Cappadocia.

Classic symptoms of coeliac disease include diarrhoea, weight loss (or stunted growth in children), and fatigue, but while coeliac disease is primarily a bowel disease, bowel symptoms may also be limited or even absent. Some patients are diagnosed with symptoms related to the decreased absorption of nutrients or with various symptoms which, although statistically linked, have no clear relationship with the malfunctioning bowel. Given this wide range of possible symptoms, the classic triad is no longer a requirement for diagnosis.

Children between 9 and 24 months tend to present with bowel symptoms and growth problems shortly after first exposure to gluten-containing products. Older children may have more malabsorption-related problems and psychosocial problems, while adults generally have malabsorptive problems. Many adults with subtle disease only have fatigue or anaemia.

The diarrhoea characteristic of coeliac disease is pale, voluminous and malodorous. Abdominal pain and cramping, bloatedness with abdominal distention (thought to be due to fermentative production of bowel gas) and mouth ulcers may be present. As the bowel becomes more damaged, a degree of lactose intolerance may develop. However, the variety of gastrointestinal symptoms that may be present in patients with coeliac disease is great, and some may have a normal bowel habit or even tend towards constipation. Frequently the symptoms are ascribed to irritable bowel syndrome (IBS), only later to be recognised as coeliac disease; a small proportion of patients with symptoms of IBS have underlying coeliac disease, and screening may be justified.

Coeliac disease leads to an increased risk of both adenocarcinoma and lymphoma of the small bowel, which returns to baseline with diet. Longstanding disease may lead to other complications, such as ulcerative jejunitis (ulcer formation of the small bowel) and stricturing (narrowing as a result of scarring).

The changes in the bowel make it less able to absorb nutrients, minerals and the fat-soluble vitamins A, D, E, and K.

Coeliac disease has been linked with a number of conditions. In many cases it is unclear whether the gluten-induced bowel disease is a causative factor or whether these conditions share a common predisposition.

Wheat varieties or subspecies containing gluten and related species such as barley and rye also induce symptoms of coeliac disease. A small minority of coeliac patients also react to oats. It is most probable that oats produce symptoms due to cross contamination with other grains in the fields or in the distribution channels. Generally, oats are therefore not recommended, though gluten-free oats are available in some locales and may be tried with caution. Other cereals, such as maize (corn), quinoa, millet, sorghum, chia seed, and rice are safe for patients to consume. Non-cereal carbohydrate-rich foods such as potatoes and bananas do not contain gluten and do not trigger symptoms.

There are several tests that can be used to assist in diagnosis. The level of symptoms may determine the order of the tests, but all tests lose their usefulness if the patient is already taking a gluten-free diet. Intestinal damage begins to heal within weeks of gluten being removed from the diet, and antibody levels decline over months. For those who have already started on a gluten-free diet, it may be necessary to perform a re-challenge with 10 g of gluten (four slices of bread) per day over 2–6 weeks before repeating the investigations. Those who experience severe symptoms (e.g. diarrhoea) earlier can be regarded as sufficiently challenged and can be tested earlier.

Combining findings into a prediction rule to guide use of endoscopy reported a sensitivity of 100% (it would identify all the cases) and specificity of 61% (it would be incorrectly positive in 39%). The prediction rule recommends that patients with high risk symptoms or positive serology should undergo endoscopy. The study defined high risk symptoms as weight loss, anaemia (haemoglobin less than 120 g/l in females and less than 130 g/l in males), or diarrhoea (more than three loose stools per day).

Serological blood tests are the first-line investigation required to make a diagnosis of coeliac disease. Serology for anti-tTG antibodies has superseded older serological tests and has a high sensitivity (99%) and specificity (>90%) for identifying coeliac disease. Modern anti-tTG assays rely on a human recombinant protein as an antigen.

Because of the major implications of a diagnosis of coeliac disease, professional guidelines recommend that a positive blood test is still followed by an endoscopy/gastroscopy and biopsy. A negative serology test may still be followed by a recommendation for endoscopy and duodenal biopsy if clinical suspicion remains high due to the 1 in 100 "false-negative" result. As such tissue biopsy is still considered the gold standard in the diagnosis of coeliac disease.

Historically three other antibodies were measured: anti-reticulin (ARA), anti-gliadin (AGA) and anti-endomysium (EMA) antibodies. Serology may be unreliable in young children, with anti-gliadin performing somewhat better than other tests in children under five. Serology tests are based on indirect immunofluorescence (reticulin, gliadin and endomysium) or ELISA (gliadin or tissue transglutaminase, tTG).

Guidelines recommend that a total serum IgA level is checked in parallel, as coeliac patients with IgA deficiency may be unable to produce the antibodies on which these tests depend ("false negative"). In those patients, IgG antibodies against transglutaminase (IgG-tTG) may be diagnostic.

Antibody testing and HLA testing have similar accuracies.

An upper endoscopy with biopsy of the duodenum (beyond the duodenal bulb) or jejunum is performed. It is important for the physician to obtain multiple samples (four to eight) from the duodenum. Not all areas may be equally affected; if biopsies are taken from healthy bowel tissue, the result would be a false negative.

Most patients with coeliac disease have a small bowel that appears normal on endoscopy; however, five concurrent endoscopic findings have been associated with a high specificity for coeliac disease: scalloping of the small bowel folds (pictured), paucity in the folds, a mosaic pattern to the mucosa (described as a cracked-mud appearance), prominence of the submucosa blood vessels, and a nodular pattern to the mucosa.

Until the 1970s, biopsies were obtained using metal capsules attached to a suction device. The capsule was swallowed and allowed to pass into the small intestine. After x-ray verification of its position, suction was applied to collect part of the intestinal wall inside the capsule. One often-utilised capsule system is the Watson capsule. This method has now been largely replaced by fibre-optic endoscopy, which carries a higher sensitivity and a lower frequency of errors.

The changes classically improve or reverse after gluten is removed from the diet, so many official guidelines recommend a repeat biopsy several (4–6) months after commencement of gluten exclusion.

In some cases a deliberate gluten challenge, followed by biopsy, may be conducted to confirm or refute the diagnosis. A normal biopsy and normal serology after challenge indicates the diagnosis may have been incorrect. Patients are warned that one does not "outgrow" coeliac disease in the same way as childhood food intolerances.

Other tests that may assist in the diagnosis are blood tests for a full blood count, electrolytes, calcium, renal function, liver enzymes, vitamin B12 and folic acid levels. Coagulation testing (prothrombin time and partial thromboplastin time) may be useful to identify deficiency of vitamin K, which predisposes patients to hemorrhage. These tests should be repeated on follow-up, as well as anti-tTG titres.

Some professional guidelines recommend screening of all patients for osteoporosis by DXA/DEXA scanning.

Coeliac disease appears to be polyfactorial, both in that more than one genetic factor can cause the disease and also more than one factor is necessary for the disease to manifest in a patient.

Almost all coeliac patients have the variant HLA DQ2 allele. However, about 20–30% of people without coeliac disease have inherited an HLA-DQ2 allele. This suggests additional factors are needed for coeliac disease to develop. Furthermore, about 5% of those people who do develop coeliac disease do not have the DQ2 gene.

The HLA-DQ2 allele shows incomplete penetrance, as the gene alleles associated with the disease appear in most patients, but are neither present in all cases nor sufficient by themselves to cause the disease.

The vast majority of coeliac patients have one of two types of HLA DQ. This gene is part of the MHC class II antigen-presenting receptor (also called the human leukocyte antigen) system and distinguishes cells between self and non-self for the purposes of the immune system. The gene is located on the short arm of the sixth chromosome, and as a result of the linkage this locus has been labeled CELIAC1.

There are 7 HLA DQ variants (DQ2 and DQ4 through DQ9). Over 95% of coeliac patients have the isoform of DQ2 or DQ8, which is inherited in families. The reason these genes produce an increase in risk of coeliac disease is that the receptors formed by these genes bind to gliadin peptides more tightly than other forms of the antigen-presenting receptor. Therefore, these forms of the receptor are more likely to activate T lymphocytes and initiate the autoimmune process.

Most coeliac patients bear a two-gene HLA-DQ2 haplotype referred to as DQ2.5 haplotype. This haplotype is composed of 2 adjacent gene alleles, DQA1*0501 and DQB1*0201, which encode the two subunits, DQ α5 and DQ β2. In most individuals, this DQ2.5 isoform is encoded by one of two chromosomes 6 inherited from parents. Most coeliacs inherit only one copy of this DQ2.5 haplotype, while some inherit it from both parents; the latter are especially at risk for coeliac disease, as well as being more susceptible to severe complications. Some individuals inherit DQ2.5 from one parent and portions of the haplotype (DQB1*02 or DQA1*05) from the other parent, increasing risk. Less commonly, some individuals inherit the DQA1*05 allele from one parent and the DQB1*02 from the other parent, called a trans-haplotype association, and these individuals are at similar risk for coeliac disease as those with a single DQ2.5 bearing chromosome 6, but in this instance disease tends not to be familial. Among the 6% of European coeliacs that do not have DQ2.5(cis or trans) or DQ8 (encoded by the haplotype DQA1*03:DQB1*0302), 4% have the DQ2.2 isoform and the remaining 2% lack DQ2 or DQ8.

The frequency of these genes varies geographically. DQ2.5 has high frequency in peoples of North and Western Europe (Basque Country, Ireland, with highest frequencies), portions of Africa, and is associated with disease in India, but is not found along portions of the West Pacific rim. DQ8, spread more globally than DQ2.5, is more prevalent from South and Central America (up to 90% phenotype frequency).

The majority of the proteins in food responsible for the immune reaction in coeliac disease are the prolamins. These are storage proteins rich in proline (prol-) and glutamine (-amin) that dissolve in alcohols and are resistant to proteases and peptidases of the gut. One region of α-gliadin stimulates membrane cells, enterocytes, of the intestine to allow larger molecules around the sealant between cells. Disruption of tight junctions allow peptides larger than 3 amino acids to enter circulation.

Membrane leaking permits peptides of gliadin that stimulate two levels of immune response, the innate response and the adaptive (T-helper cell mediated) response. One protease resistant peptide from α-gliadin contains a region that stimulates lymphocytes and results in the release of interleukin-15. This innate response to gliadin results in immune system signalling that attracts inflammatory cells and increases the release inflammatory chemicals. The strongest and most common adaptive response to gliadin is directed toward a α2-gliadin fragment of 33 amino acids in length. The response to 33mer occurs in most coeliacs who have a DQ2 isoform. This peptide, when altered by intestinal transglutaminase, has a high density of overlapping T-cell epitopes. This increases the likelihood that the DQ2 isoform will bind and stay bound to peptide when recognised by T-cells. Gliadin in wheat is the best-understood member of this family, but other prolamins exist and hordein (from barley), and secalin (from rye) may contribute to coeliac disease. However, not all prolamins will cause this immune reaction and there is ongoing controversy on the ability of avenin (the prolamin found in oats) to induce this response in coeliac disease.

Anti-transglutaminase antibodies to the enzyme tissue transglutaminase (tTG) are found in an overwhelming majority of cases. Tissue transglutaminase modifies gluten peptides into a form that may stimulate the immune system more effectively.

Stored biopsies from suspected coeliac patients has revealed that autoantibody deposits in the subclinical coeliacs are detected prior to clinical disease. These deposits are also found in patients who present with other autoimmune diseases, anaemia or malabsorption phenomena at a much increased rate over the normal population. Endomysial component of antibodies (EMA) to tTG are believed to be directed toward cell surface transglutaminase, and these antibodies are still used in confirming a coeliac disease diagnosis. However, a 2006 study showed that EMA-negative coeliac patients tend to be older males with more severe abdominal symptoms and a lower frequency of "atypical" symptoms including autoimmune disease. In this study the anti-tTG antibody deposits did not correlate with the severity of villous destruction. These findings, coupled with recent work showing that gliadin has an innate response component, suggests that gliadin may be more responsible for the primary manifestations of coeliac disease whereas tTG is a bigger factor in secondary effects such as allergic responses and secondary autoimmune diseases. In a large percentage of coeliac patients the anti-tTG antibodies also recognise a rotavirus protein called VP7. These antibodies stimulate monocytes proliferation and rotavirus infection might explain some early steps in the cascade of immune cell proliferation. Indeed, earlier studies of rotavirus damage in the gut showed this causes a villous atrophy. This suggests that viral proteins may take part in the initial flattening and stimulate self-crossreactive anti-VP7 production. Antibodies to VP7 may also slow healing until the gliadin mediated tTG presentation provides a second source of crossreactive antibodies.

The inflammatory process, mediated by T cells, leads to disruption of the structure and function of the small bowel's mucosal lining, and causes malabsorption as it impairs the body's ability to absorb nutrients, minerals and fat-soluble vitamins A, D, E and K from food. Lactose intolerance may be present due to the decreased bowel surface and reduced production of lactase but typically resolves once the condition is treated.

Alternative causes of this tissue damage have been proposed and involve release of interleukin 15 and activation of the innate immune system by a shorter gluten peptide (p31–43/49). This would trigger killing of enterocytes by lymphocytes in the epithelium. The villous atrophy seen on biopsy may also be due to unrelated causes, such as tropical sprue, giardiasis and radiation enteritis. While positive serology and typical biopsy are highly suggestive of coeliac disease, lack of response to diet may require these alternative diagnoses to be considered.

There are various theories as to what determines whether a genetically susceptible individual will go on to develop coeliac disease. Major theories include infection by rotavirus or human intestinal adenovirus. Some research has suggested that smoking is protective against adult onset coeliac disease.

A 2005 prospective and observational study found that timing of the exposure to gluten in childhood was an important risk modifier. People exposed to wheat, barley, or rye before the gut barrier has fully developed (within the first three months after birth) had five times the risk of developing coeliac disease relative to those exposed at between 4 to 6 months after birth. Those exposed even later than six months after birth, were found to have only a slightly increased risk relative to those exposed at between 4 to 6 months after birth. However a 2006 study with similar numbers found just the reverse, that early introduction of grains was protective. Breastfeeding may also reduce risk. A meta-analysis indicates that prolonging breastfeeding until the introduction of gluten-containing grains into the diet was associated with a 52% reduced risk of developing coeliac disease in infancy; whether this persists into adulthood is not clear.

At present, the only effective treatment is a life-long gluten-free diet. No medication exists that will prevent damage, or prevent the body from attacking the gut when gluten is present. Strict adherence to the diet allows the intestines to heal, leading to resolution of all symptoms in most cases and, depending on how soon the diet is begun, can also eliminate the heightened risk of osteoporosis and intestinal cancer. Dietician input is generally requested to ensure the patient is aware which foods contain gluten, which foods are safe, and how to have a balanced diet despite the limitations. In many countries gluten-free products are available on prescription and may be reimbursed by health insurance plans. More manufacturers are producing gluten-free products, some of which are almost indistinguishable from their gluten-containing counterparts.

The diet can be cumbersome; failure to comply with the diet may cause relapse. The term "gluten-free" is generally used to indicate a supposed harmless level of gluten rather than a complete absence. The exact level at which gluten is harmless is uncertain and controversial. A recent systematic review tentatively concluded that consumption of less than 10 mg of gluten per day is unlikely to cause histological abnormalities, although it noted that few reliable studies had been done. Regulation of the label "gluten-free" varies widely by country. For example, in the United States the term "gluten-free" is not yet regulated. The current international Codex Alimentarius standard, established in 1981, allows for 50 mg N/100 g on dry matter, although a proposal for a revised standard of 20 ppm in naturally gluten-free products and 200 ppm in products rendered gluten-free has been accepted. Gluten-free products are usually more expensive and harder to find than common gluten-containing foods. Since ready-made products often contain traces of gluten, some coeliacs may find it necessary to cook from scratch.

Even while on a diet, health-related quality of life (HRQOL) may be lower in people with coeliac disease. Studies in the United States have found that quality of life becomes comparable to the general population after staying on the diet while studies in Europe have found that quality of life remains lower, although the surveys are not quite the same. Men tend to report more improvement than women. Some have persisting digestive symptoms or dermatitis herpetiformis, mouth ulcers, osteoporosis and resultant fractures. Symptoms suggestive of irritable bowel syndrome may be present, and there is an increased rate of anxiety, fatigue, dyspepsia and musculoskeletal pain.

A tiny minority of patients suffer from refractory disease, which means they do not improve on a gluten-free diet. This may be because the disease has been present for so long that the intestines are no longer able to heal on diet alone, or because the patient is not adhering to the diet, or because the patient is consuming foods that are inadvertently contaminated with gluten. If alternative causes have been eliminated, steroids or immunosuppressants (such as azathioprine) may be considered in this scenario.

There is significant debate as to the benefits of screening. Some studies suggest that early detection would decrease the risk of osteoporosis and anaemia. In contrast, a cohort studied in Cambridge suggested that people with undetected coeliac disease had a beneficial risk profile for cardiovascular disease (less overweight, lower cholesterol levels).

Due to its high sensitivity, serology has been proposed as a screening measure, because the presence of antibodies would detect previously undiagnosed cases of coeliac disease and prevent its complications in those patients. Serology may also be used to monitor adherence to diet: in those who still ingest gluten, antibody levels remain elevated.

In the United Kingdom, the National Institute for Health and Clinical Excellence (NICE) recommends screening for coeliac disease in patients with newly diagnosed chronic fatigue syndrome and irritable bowel syndrome.

Other clinical scenarios in which screening may be justified include type 1 diabetes, unexplained iron-deficiency anaemia, Down's syndrome, Turner's syndrome, lupus, and autoimmune thyroid disease.

The prevalence of clinically diagnosed disease (symptoms prompting diagnostic testing) is 0.05–0.27% in various studies. However, population studies from parts of Europe, India, South America, Australasia and the USA (using serology and biopsy) indicate that the prevalence may be between 0.33 and 1.06% in children (5.66% in one study of Sahrawi children) and 0.18–1.2% in adults. People of African, Japanese and Chinese descent are rarely diagnosed; this reflects a much lower prevalence of the genetic risk factors. Population studies also indicate that a large proportion of coeliacs remain undiagnosed; this is due to many clinicians being unfamiliar with the condition.

A large multicentre study in the U.S. found a prevalence of 0.75% in not-at-risk groups, rising to 1.8% in symptomatic patients, 2.6% in second-degree relatives of a patient with coeliac disease and 4.5% in first-degree relatives. This profile is similar to the prevalence in Europe. Other populations at increased risk for coeliac disease, with prevalence rates ranging from 5% to 10%, include individuals with Down and Turner syndromes, type 1 diabetes, and autoimmune thyroid disease, including both hyperthyroidism (overactive thyroid) and hypothyroidism (underactive thyroid).

Historically, coeliac disease was thought to be rare, with a prevalence of about 0.02%. Recent increases in the number of reported cases may be due to changes in diagnostic practice.

Most mainstream Christian churches offer their communicants gluten-free alternatives to the sacramental bread, usually in the form of a rice-based cracker or gluten-free bread. These include United Methodist, Christian Reformed, Episcopal, Lutheran, The Church of Jesus Christ of Latter-day Saints, and many others.

The Jewish festival of Pesach (Passover) may present problems with its obligation to eat matzo, which is unleavened bread made in a strictly controlled manner from wheat, barley, spelt, oats, or rye. This rules out many other grains that are normally used as substitutes for people with gluten sensitivity, especially for Ashkenazi Jews who also avoid rice. Many kosher for Passover products avoid grains altogether and are therefore gluten-free. Potato starch is the primary starch used to replace the grains. Consuming matzo is mandatory on the first night of Pesach only. Jewish law holds that a person should not seriously endanger one's health in order to fulfill a commandment. Thus, a person with severe coeliac disease is not required, or even allowed, to eat any matzo other than gluten-free matzo. The most commonly used gluten-free matzo is made from oats.

Aretaeus of Cappadocia, living in the second century, recorded a malabsorptive syndrome with chronic diarrhoea. His "Cœliac Affection" (coeliac from Greek κοιλιακός koiliakos, abdominal) gained the attention of Western medicine when Francis Adams presented a translation of Aretaeus' work at the Sydenham Society in 1856. The patient had stomach pain and was atrophied, pale, feeble and incapable of work. The diarrhoea manifested as loose stools that were white, malodorous and flatulent and the disease was intractable and liable to periodic return. The problem, Aretaeus believed, was a lack of heat in the stomach necessary to digest the food and a reduced ability to distribute the digestive products throughout the body, this incomplete digestion resulting in the diarrhoea, He regarded this as an affliction of the old and more commonly affecting women, explicitly excluding children. The cause, according to Aretaeus, was sometimes either another chronic disease or even consuming "a copious draught of cold water".

The paediatrician Samuel Gee gave the first modern-day description of the condition in a lecture at Hospital for Sick Children, Great Ormond Street, London in 1887. Gee acknowledged earlier descriptions and terms for the disease and adopted the same term as Aretaeus (coeliac disease). Unlike Aretaeus, he included children in the scope of the affliction, particularly those between one and five years old. Gee found the cause to be obscure and failed to spot anything abnormal during post-mortem examination (the lining of the small bowel quickly deteriorates on death). He perceptively stated "if the patient can be cured at all, it must be by means of diet." Gee recognised that milk intolerance is a problem with coeliac children and that highly starched foods should be avoided. However, he forbade rice, sago, fruit and vegetables, which all would have been safe to eat and he recommended raw meat as well as thin slices of toasted bread. Gee highlighted particular success with a child "who was fed upon a quart of the best Dutch mussels daily". However, the child could not bear this diet for more than one season.

Christian Archibald Herter, an American physician, wrote a book in 1908 on children with coeliac disease, which he called "intestinal infantilism". He noted their growth was retarded and that fat was better tolerated than carbohydrate. The eponym Gee-Herter disease was sometimes used to acknowledge both contributions. Sydney V. Haas, an American paediatrician, reported positive effects of a diet of bananas in 1924. This diet remained in vogue until the actual cause of coeliac disease was determined.

While a role for carbohydrates had been suspected, the link with wheat was not made until the 1940s by the Dutch paediatrician Dr Willem Dicke. It is likely that clinical improvement of his patients during the Dutch famine of 1944 (during which flour was sparse) may have contributed to his discovery. The link with the gluten component of wheat was made in 1952 by a team from Birmingham, England. Villous atrophy was described by British physician John W. Paulley in 1954. Paulley was able to examine biopsies taken from patients during abdominal operations. Dr Margo Shiner, working on Prof Sheila Sherlock's team at the Postgraduate Medical School in London, described the principles of small bowel biopsy in 1956.

Throughout the 1960s other features of coeliac disease were elucidated. Its hereditary character was recognised in 1965. In 1966 dermatitis herpetiformis was linked to gluten sensitivity.

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Bloating is any abnormal general swelling, or increase in diameter of the abdominal area. As a symptom, the patient feels a full and tight abdomen, which may cause abdominal pain sometimes accompanied by borborygmus.

Bloating may have several causes, the most common being accumulation of liquids and intestinal gas. Ascites is the proper medical term for abdominal bloating caused by excessive accumulation of liquid inside the cavity.

Important, but uncommon causes of abdominal bloating, include large intra-abdominal tumors, such as those arising from ovarian, liver, uterus and stomach cancer; and megacolon, an abnormal dilation of the colon, due to some diseases, such as Chagas disease, a parasitic infection. Gaseous bloating may be a consequence of cardiopulmonary resuscitation procedures, due to the artificial mouth-to-mouth insufflation of air. In some animals, like cats, dogs and cattle, gastric dilatation-volvulus, or bloat also occurs when gas is trapped inside the stomach and a gastric torsion or volvulus prevents it from escaping.

Bloating from irritable bowel syndrome (IBS) is of unknown origin but often results from an insult to the gut, and as such can overlap with infective diarrhea, celiac, and inflammatory bowel diseases. IBS is a brain-gut dysfunction that causes visceral hypersensitivity and results in bloating in association with recurrent diarrhea (or constipation) and abdominal pain. While there is no direct treatment for the underlying pathology of IBS, the symptom of bloating can be well managed through dietary changes that prevent the over-reaction of the gastrocolic reflex. Having soluble fiber foods and supplements, substituting dairy with soy or rice products, being careful with fresh fruits and vegetables that are high in insoluble fiber, and eating regular small amounts can all help to lessen the symptoms of IBS (Van Vorous 2000). Foods and beverages to be avoided or minimized include red meat, oily, fatty and fried products, dairy (even when there is no lactose intolerance), solid chocolate, coffee (regular and decaffeinated), alcohol, carbonated beverages, especially those also containing sorbitol, and artificial sweeteners (Van Vorous 2000).

Postmortem bloating occurs in cadavers, due to the formation of gases by bacterial action and putrefaction of the internal tissues of the abdomen and the inside of the intestines.

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Source : Wikipedia