Lactose intolerance Classification and external resources
Lactose (disaccharide of β-D-galactose & β-D-glucose) is normally split by lactase. Lactose (also referred to as milk sugar) is a Sugar which is found most notably in Milk. A disaccharide is a Sugar (a Carbohydrate) composed of two Monosaccharides 'Disaccharide' is one of the four chemical groupings of carbohydrates ( Lactase (LCT a part of the β-galactosidase family of Enzymes is a Glycoside hydrolase involved in the Hydrolysis
ICD-10	E73.
ICD-9	271.3
OMIM	223100 150220
DiseasesDB	7238
MedlinePlus	000276
eMedicine	med/3429  ped/1270
MeSH	D007787

Lactose intolerance is the inability to metabolize lactose, a sugar found in milk and other dairy products, because the required enzyme lactase is absent or its availability is lowered. The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify Diseases The International Statistical Classification of Diseases and Related Health Problems 10th Revision ( ICD -10) is a coding of diseases and signs symptoms abnormal findings E00-E35 - Endocrine diseases (E00-E07 Thyroid gland / Thyroid hormone ( Congenital iodine-deficiency syndrome ( The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify Diseases The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. The Mendelian Inheritance in Man project is a Database that catalogues all the known Diseases with a genetic component, and—when possible—links them The Diseases Database is a free Website that provides information about the relationships between medical conditions Symptoms, and Medications. MedlinePlus, with the MedlinePlus Medical Encyclopedia, is a website network containing Health information from the world's largest medical Library eMedicine is an online clinical medical knowledge base that was founded in 1996 by Scott Plantz and Richard Lavely two medical doctors Medical Subject Headings ( MeSH) is a huge Controlled vocabulary (or metadata system for the purpose of indexing journal articles and books Metabolism is the set of Chemical reactions that occur in living Organisms in order to maintain Life. Lactose (also referred to as milk sugar) is a Sugar which is found most notably in Milk. Milk is an opaque white liquid produced by the Mammary glands of female Mammals (including Monotremes. A dairy is a facility for the extraction and processing of animal Milk &mdashmostly from goats or cows, but also from buffalo, Sheep Lactase (LCT a part of the β-galactosidase family of Enzymes is a Glycoside hydrolase involved in the Hydrolysis It is estimated that 70% of adult humans are lactose intolerant. ^[1]

Overview

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. A disaccharide is a Sugar (a Carbohydrate) composed of two Monosaccharides 'Disaccharide' is one of the four chemical groupings of carbohydrates ( Lactase (LCT a part of the β-galactosidase family of Enzymes is a Glycoside hydrolase involved in the Hydrolysis Lactose (also referred to as milk sugar) is a Sugar which is found most notably in Milk. 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). An operon is a functioning unit of key Nucleotide sequences including an operator, a common Promoter, and one or more structural Genes, The gut flora are the Microorganisms that normally live in the Digestive tract and can perform a number of useful functions for their hosts Metabolism is the set of Chemical reactions that occur in living Organisms in order to maintain Life. Fermentation is the process of deriving energy from the oxidation of organic compounds such as carbohydrates using an endogenous electron acceptor which is Hydrogen (ˈhaɪdrədʒən is the Chemical element with Atomic number 1 Carbon dioxide ( Chemical formula:) is a Chemical compound composed of two Oxygen Atoms covalently bonded to a single Methane is a Chemical compound with the molecular formula. It is the simplest Alkane, and the principal component of Natural gas. This, in turn, may cause a range of unpleasant abdominal symptoms, including stomach cramps, bloating, and flatulence. Cramps, sometimes called Charley horses are unpleasant often painful sensations caused by contraction or over shortening of Muscles Cramps can be caused by cold Bloating is any abnormal general Swelling, or increase in diameter of the abdominal area Flatulence is the production of a mixture of gases in the digestive tract of Mammals that are byproducts of the digestion process 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, thereby preventing the colon from reabsorbing water, and causing osmotic diarrhea. Sorbitol, also known as glucitol, is a Sugar alcohol that the body metabolises slowly Mannitol or hexan-123456-hexol (C6H8(OH6 is a Polyol that is used as an osmotic Diuretic agent and a Xylitol (from Greek ξύλον - xyl, "wood" + suffix - itol, used to denote sugar alcohols is an Organic compound with the formula (CHOH3(CH2OH2 Osmosis is the Diffusion of a solvent (frequently water through a semi-permeable membrane, from a solution of low solute concentration (high water potential The colon is a storage tube for solid wastes The main function of the colon appears to be extraction of Water and salts from Feces. In Medicine, diarrhea, also spelled diarrhoea (see spelling differences) is frequent loose or liquid Bowel movements Acute diarrhea

Classification

There are three major types of lactose intolerance:^[2]

1. Primary lactose intolerance. Environmentally induced when weaning a child in non dairy consuming societies. ^[3] This is found in many Asian and African cultures, where industrialized and commercial dairy products are uncommon.
2. Secondary lactose intolerance. Environmentally induced, resulting from certain gastrointestinal diseases, including exposure to intestinal parasites such as giardia. All diseases that pertain to the Gastrointestinal tract are labelled as digestive diseases. Intestinal parasites are Parasites that populate the Gastro-intestinal tract. Giardia lamblia (synonymous with Lamblia intestinalis and Giardia duodenalis) is a Flagellated Protozoan ^[4][5] In such cases the production of lactase may be permanently disrupted. ^[4][5][6] A very common cause of temporary lactose intolerance is gastroenteritis, particularly when the gastroenteritis is caused by rotavirus. Gastroenteritis (also known as gastro, gastric flu, and stomach flu, although unrelated to Influenza) is Inflammation of the Rotavirus is a Genus of Double-stranded RNA virus in the family Reoviridae. Another form of temporary lactose intolerance is lactose overload in infants. ^[7]
3. Congenital lactase deficiency. A genetic disorder which prevents enzymatic production of lactase. Present at birth, and diagnosed in early infancy.

Lactase biology

The enzyme lactase, also called beta-D-galactosidase, is synthesized if at least one of the two genes for it are present. Only when both gene expressions are affected is lactase enzyme synthesis reduced, which in turn reduces lactose digestion. ^[8]. Lactase persistence, allowing lactose digestion to proceed, is the dominant allele. Physiological lactose intolerance, therefore, is an autosomal recessive trait.

However, 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^[9]. For a topic outline on this subject see List of basic Japan topics.

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). Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands Lactase (LCT a part of the β-galactosidase family of Enzymes is a Glycoside hydrolase involved in the Hydrolysis Weaning is the process of gradually introducing a Mammal Infant, either human or animal to what will be its adult diet and withdrawing the supply of its mother's 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 results in a bypass of the common 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. In biology mutations are changes to the Nucleotide sequence of the Genetic material of an organism A chromosome is an organized structure of DNA and Protein that is found in cells.

Pathological lactose intolerance can be caused by Coeliac disease, which damages the villi in the small intestine that produce lactase. Coeliac 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. A gluten-free diet is recommended amongst other things in the treatment of Coeliac disease and Wheat allergy.

Certain people who report problems with consuming lactose are not actually lactose intolerant. In a study of 323 Sicilian adults, Carroccio et al. Sicily ( Italian and Sicilian: Sicilia) is an autonomous region of Italy. (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.

Lactose intolerance by group

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

The statistical significance varies greatly depending on number of people sampled. In Statistics, a result is called statistically significant if it is unlikely to have occurred by Chance.

Lactose intolerance levels also increase with age. At ages 2 - 3 yrs. , 6 yrs. , and 9 - 10 yrs. , the amount of lactose intolerance is, respectively:

• 6% to 15% in white Americans and northern Europeans
• 18%, 30%, and 47% in Mexican Americans
• 25%, 45%, and 60% in black South Africans
• approximately 30%, 80%, and 85% in Chinese and Japanese
• 30–55%, 90%, and >90% in Mestizos of Peru^[27][28]

Chinese and Japanese populations typically lose between 80 and 90 percent of their ability to digest lactose within three to four years of weaning. See also History of Mexican-Americans Mexican Americans are Americans of Mexican ancestry The Republic of South Africa (also known by other official names) is a country located at the southern tip of the continent of Africa Mestizo is a Spanish term that was coined during the Spanish Empire to refer to people of mixed European and Amerindian ancestry in Latin Peru (Perú Piruw Piruw officially the Republic of Peru ( reˈpuβlika del peˈɾu is a country in western South America. The term Chinese people may refer to any of the following A person who resides in and holds citizenship of the People's Republic of China (including Hong The are the dominant Ethnic group of Japan. Worldwide approximately 130 million people are of Japanese descent of these approximately 127 million are residents of Japan Most Japanese can consume 200 ml (8 fl oz) of milk without severe symptoms (McGee 2004; Swagerty et al, 2002). ^[9]

Ashkenazi Jews can keep 20 - 30 percent of their ability to digest lactose for many years. Ashkenazi Jews, also known as Ashkenazic Jews or Ashkenazim ( Hebrew: אַשְׁכֲּנָזִים, ˌaʃkəˈnazim sing ^{[27] [29][30]} 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. ^[31]

Diagnosis

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. ^[32] 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.

When considering the need for confirmation, it is important to distinguish lactose intolerance from milk allergy, which is an abnormal immune response (usually) to milk proteins. An immune system is a collection of mechanisms within an Organism that protects against Disease by identifying and killing Pathogens and Tumor Since lactose intolerance is the normal state for most adults on a worldwide scale, and not considered a disease condition, a medical diagnosis is not normally required. However, if confirmation is necessary, three tests are available:

Hydrogen breath test

In a hydrogen breath test, after an overnight fast, 50 grams of lactose (in a solution with water) are swallowed. A hydrogen breath test (or HBT) is used as a clinical medical Diagnosis for people with Irritable bowel syndrome, and common Food intolerances For other uses of the words gram or gramme see Gram (disambiguation. If the lactose cannot be digested, enteric bacteria metabolize it and produce hydrogen. Hydrogen (ˈhaɪdrədʒən is the Chemical element with Atomic number 1 This 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. Fructose malabsorption or Dietary Fructose Intolerance is a digestive disorder of the Small intestine in which the Fructose carrier in Enterocytes

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 largley supplanted by breath testing.

Stool acidity

Can be used to diagnose lactose intolerance in small infants, for whom other forms of testing are risky or impractical. ^[33]

Intestinal biopsy

An intestinal biopsy can confirm lactose intolerance following discovery of elevated hydrogen in the hydrogen breath test. ^[34]. However, given the invasive nature of this test, and the need for a highly specialized laboratory to measure lactase enzymes or mRNA in the biposy tissue, this approach is used almost exclusively in clinical research.

History of diagnosis

The ancient Greek physician Hippocrates (460-370 B. The term ancient Greece refers to the period of Greek history lasting from the Greek Dark Ages ca Hippocrates of Cos II or Hippokrates of Kos ( ca. 460 BC – ca C. ) first noted gastrointestinal upset and skin problems in some who consumed milk;^[35] 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. The United Nations ( UN) is an International organization whose stated aims are to facilitate cooperation in International law, International security A famine is a widespread shortage of food that may apply to any Faunal species which phenomenon is usually accompanied by regional Malnutrition, Starvation 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. The term " first world " refers to countries that are capitalist, which are technologically advanced and whose Third World is a name given to nations that are generally considered to be underdeveloped economically

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. Medicine is the art and science of healing It encompasses a range of Health care practices evolved to maintain and restore Human Health by the 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. The American Civil Rights Movement (1955–1968 refers to the reform movements in the United States aimed at abolishing racial discrimination against African

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. Food science is a discipline concerned with all technical aspects of Food, beginning with Harvesting or slaughtering, and ending with its Cooking

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. A hypothesis (from Greek) consists either of a suggested explanation for a phenomenon (an event that is observable or of a reasoned proposal suggesting a possible Lactase (LCT a part of the β-galactosidase family of Enzymes is a Glycoside hydrolase involved in the Hydrolysis Monosaccharides (from Greek monos: single sacchar: sugar are the most basic unit of Carbohydrates They consist of one sugar and Some form of human-bacteria symbiosis was proposed as a means of producing lactase in the human digestive tract. This article is about the biological phenomenon for other uses see Symbiosis (disambiguation The term symbiosis (from the Greek 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.

History of genetic prevalence

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. The Neolithic (from Greek νεολιθικός — neolithikos from νέος neos, "new" + λίθος lithos It is believed that most of the milk was used to make mature cheeses which are mostly lactose free. Cheese is a Food made from Milk, usually the milk of cows, Buffalo, Goats or sheep, by coagulation.

Roman authors recorded that the people of northern Europe, particularly Britain and Germany drank unprocessed milk (as opposed to the Romans who made cheese). Roman Britain refers to those parts of the island of Great Britain controlled by the Roman Empire between AD 43 and 410 The Germanic peoples are a historical group of Indo-European -speaking peoples originating in Northern Europe and identified by their use of the Germanic Cheese is a Food made from Milk, usually the milk of cows, Buffalo, Goats or sheep, by coagulation. 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. The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located Germany, officially the Federal Republic of Germany ( ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant is a Country in Central Europe. Terminology and usage As a cultural term "Scandinavia" has no official definition and is subject to usage by those who identify with the culture in question as well Italy (Italia officially the Italian Republic, (Repubblica Italiana is located on the Italian Peninsula in Southern Europe, and on the two largest ^[36]

In east Asia, historical sources also attest that the Chinese did not consume milk, whereas the nomads that lived on the borders did. China ( Wade-Giles ( Mandarin) Chung¹kuo² is a cultural region, an ancient Civilization, and depending on perspective a National 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. Mongolia (mɒŋˈɡoʊliə, literally Mongol country/nation,) is a Landlocked Country in East In physical Geography, a steppe ( German, from степь - "a flat and arid land" степ - /stɛp/ тал - tal дала - /dɑlɑ/ pronounced 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. Kumis ( Turkish:kımız Mongolian:airag is a fermented dairy product traditionally made from mare's milk Fermentation in Food processing typically refers to the conversion of Sugar to Alcohol using Yeast under Anaerobic conditions

The African Fulani have a nomadic origin and their culture once completely revolved around cow, goat, and sheep herding. The Sokoto Caliphate is an Islamic spiritual community in Nigeria, led by the Sultan of Sokoto, Sa’adu Abubakar. Dairy products were once a large source of nutrition for them. A dairy is a facility for the extraction and processing of animal Milk &mdashmostly from goats or cows, but also from buffalo, Sheep 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. Guinea, officially Republic of Guinea (pronounced /ˈgɪni/ République de Guinée is a country in West Africa, formerly known as French Guinea Burkina Faso (bɚˌkiːnəˈfɑːsoʊ burr-KEE-na FAH-soh) also known by its short-form name Burkina, is a Landlocked nation in West Africa Mali, officially the Republic of Mali (République du Mali is a Landlocked nation in Western Africa. Nigeria, officially named the Federal Republic of Nigeria, is a federal Constitutional republic comprising thirty-six states and one Federal Niger ( or /ˈnaɪdʒɚ/) officially the Republic of Niger, is a Landlocked country in Western Africa, named after the Niger River. The Republic of Cameroon is a unitary republic of central and western Africa. Chad (Tchad تشاد Tshād) officially known as the Republic of Chad, is a Landlocked country in Central Africa.

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. "Sverige" redirects here For other uses see Sweden (disambiguation and Sverige (disambiguation. 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. The Tutsi are one of three native Peoples of the nations of Rwanda and Burundi in central Africa, the other two being the Twa Whatever the precise origin in time and place, most modern Western 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). Western Europe at its most general meaning means 'all the countries in the West of Europe ' Sub-Saharan Africa is a geographical term used to describe the area of the African continent which lies south of the Sahara, or those African countries The Pacific Ocean contains an estimated 20000 to 30000 Islands (the exact number has yet to be precisely determined

The Maasai ability to consume dairy without exhibiting symptoms may be due to a different genetic mutation than Westeners. The Maasai are an indigenous African Ethnic group of semi-nomadic people located in Kenya and northern Tanzania. ^[37] 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. ^[38] A noncoding variation in the MCM6 gene has been strongly associated with adult type hypolactasia. ^[39]

Managing lactose intolerance

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^[40]). 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 in 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.

Avoiding lactose-containing products

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. "NIH" redirects here For other meanings of NIH see NIH (disambiguation. "^[41] Label reading is essential as commercial terminology varies according to language and region. ^[34]

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

Dairy products

Lactose is a water soluble molecule. Therefore fat percentage and the curdling process have an impact on which foods may be tolerated. Curd is a Dairy product obtained by curdling (coagulating Milk with Rennet or an edible Acidic substance such as Lemon juice In the curdling process lactose is found in the water portion along with whey and casein, but is not found in the fat portion. Curd is a Dairy product obtained by curdling (coagulating Milk with Rennet or an edible Acidic substance such as Lemon juice Whey or milk plasma is the liquid remaining after Milk has been Curdled and strained it is a By-product of the manufacture of Cheese See Casein paint for information about casein usage in artistic painting 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. Diet food (or dietetic food) refers to any food or drink whose recipe has been altered in some way to make it part of a body modification diet. Milk is an opaque white liquid produced by the Mammary glands of female Mammals (including Monotremes.

Milk. Human milk has the highest lactose percentage at around 9%. Breast milk refers to the Milk produced by a mother to feed her baby Unprocessed cow milk has 4. 7% lactose. Unprocessed milk from other mammals contains similar lactose percentages (goat milk 4. Milk is an opaque white liquid produced by the Mammary glands of female Mammals (including Monotremes. 1%,^[42] buffalo 4. The biological Subfamily bovines includes a diverse group of 10 species of medium to large sized Ungulates including domestic Cattle, Bison, Water 86%,^[43] yak 4. The yak ( Bos grunniens) is a long-haired Bovine found throughout the Himalayan region of south Central Asia, the Qinghai - 93%,^[44] sheep milk 4. Sheep's milk (or ewe's milk) is the Milk of Domestic sheep. Though not widely drunk in any modern culture sheep's milk is commonly used to make cultured 6%)

Butter. The butter making process separates milk's water components from the fat components. Lactose, being a water soluble molecule, will not be present in the butter unless milk solids are added to the ingredients.

Yogurt and kefir. For the Islamic term see Kaffir. Kefir (alternately keefir, kephir, kewra, talai, mudu kekiya 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. Yoghurt, yogurt, yoghourt, youghurt or yogourt (see spelling below is a 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. This article describes a kind of cheese produced primarily in Canada and the United States. 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. Cheddar cheese is a relatively hard pale yellow to off-white and sometimes sharp-tasting Cheese from the English village of Cheddar, in Somerset Milk is an opaque white liquid produced by the Mammary glands of female Mammals (including Monotremes. In addition, the traditional aging methods of cheese (over 2 years) reduces their lactose content to practically nothing. [1] 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.

Buttermilk, sour cream and ice cream, like yogurt, if made the traditional way, will generally be quite tolerable, but most modern brands add milk solids. ^[45] Consult labels. ^[46]

Examples of lactose levels in foods. As scientific consensus has not been reached concerning lactose percentage analysis methods ^[47] (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. ^[41] These quantities are to be treated as guidelines only.

Dairy product	Lactose Content
Yogurt, plain, low-fat, 240 mL	5 g
Milk, reduced fat, 240 mL	11 g
Swiss cheese, 28 g	1 g
Ice cream, 120 mL	6 g
Cottage cheese, 120 mL	2–3 g

Lactose in non-dairy products

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^[48] (sausages/hot dogs, sliced meats, Pâtés), gravy stock powder, margarines^[49], sliced breads,^[50][51] breakfast cereals,^[48] dried fruit, processed foods, medications, preprepared meals, meal replacement (powders and bars), protein supplements (powders and bars). Whey or milk plasma is the liquid remaining after Milk has been Curdled and strained it is a By-product of the manufacture of Cheese Whey or milk plasma is the liquid remaining after Milk has been Curdled and strained it is a By-product of the manufacture of Cheese Milk is an opaque white liquid produced by the Mammary glands of female Mammals (including Monotremes. Food additives are substances added to food to preserve flavour or improve its taste and appearance A sausage is a prepared Food, usually made from Ground meat, animal fat salt and Spices (sometimes with other ingredients such as herbs typically packed A hot dog is a type of fully-cooked cured and/or smoked moist Sausage of soft even texture and flavor Pâté (French pronunciation; RP pronunciation; General American pronunciation) Margarine (ˈmɑrdʒərɨn /ˈmɑrdʒəriːn/ or /ˈmɑrgəriːn/ as a generic term can indicate any of a wide range of Butter substitutes Bread is a Staple food prepared by Baking a Dough of Flour and Water. The term fruit has different meanings dependent on context and the term is not synonymous in Food preparation and Biology. Food processing is the set of methods and techniques used to transform raw Ingredients into Food or to transform food into other forms for consumption by Medication, also referred to as medicine, can be loosely defined as any substance intended for use in the diagnosis cure mitigation treatment or prevention of disease

Kosher products labeled pareve are free of milk. See also Kashrut Kosher foods are those that conform to the regulations of Jewish religion However, if a "D" (for "Dairy) is present next to the circled "K," "U," or other hechsher, the food likely contains milk solids^[48] (although it may also simply indicate that the product was produced on equipment shared with other products containing milk derivatives). See also Kashrut A hechsher (IPA /hɛxʃəʁ/ הכשר Hebrew: "kosher approval", plural hechsherim

Alternative products

Milk. The dairy industry has created quality low-lactose or lactose-free products to replace regular dairy. A dairy is a facility for the extraction and processing of animal Milk &mdashmostly from goats or cows, but also from buffalo, Sheep 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 almost 0%. Finland has had "HYLA" (acronym for hydrolysed lactose) products available for many years, even though the number of lactose intolerant people there is relatively small. Finland, officially the Republic of Finland ( is a Nordic country situated in the Fennoscandian region of northern Europe. These low-lactose level cow's milk products, ranging from ice cream to cheese, use a Valio patented chromatographic separation method to remove lactose. Valio is one of the biggest companies in Finland and mostly produces Dairy products such as Cheese, powdered ingredients Butter, Yoghurt 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 2 - 4 times more than equivalent products containing lactose. Valio also markets these products in Sweden. "Sverige" redirects here For other uses see Sweden (disambiguation and Sverige (disambiguation.

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). Yoghurt, yogurt, yoghourt, youghurt or yogourt (see spelling below is a

Plant based milks and derivatives are the only ones to be 100% lactose free (soy milk, almond milk, oat milk, rice milk, peanut milk). Plant milk is a general term for any non- Dairy substitute for animal-based Milk products Soy milk (also called soya milk, soybean milk, or soy juice) and sometimes referred to as soy drink/beverage is a beverage made from Almond milk is a milky drink made from ground Almonds Unlike animal Milk, almond milk contains no Cholesterol or Lactose and can be used Grain milk is a Milk substitute made from fermented grain or from flour Rice milk is a kind of Grain milk processed from Rice. It is mostly made from Brown rice and commonly unsweetened the sweetness in most rice milk Peanut milk is a non-dairy beverage created using Peanuts water and an additional sweetener

Lactase supplementation

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 (LCT a part of the β-galactosidase family of Enzymes is a Glycoside hydrolase involved in the Hydrolysis ^[52][53]

Lactase enzymes similar to the those produced in the small intestines of humans are produced industrially by fungi of the genus aspergillus. A fungus (ˈfʌŋgəs is a eukaryotic Organism that is a member of the kingdom Fungi (ˈfʌndʒaɪ A genus (plural genera from Γένος Latin genus "descent family type gender" is a low-level Taxonomic Aspergillus is a Genus of around 200 Molds found throughout much of nature worldwide 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,^[54] 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. Lactase (LCT a part of the β-galactosidase family of Enzymes is a Glycoside hydrolase involved in the Hydrolysis Lactose (also referred to as milk sugar) is a Sugar which is found most notably in Milk.

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. Yeasts are a growth form of eukaryotic Microorganisms classified in the kingdom Fungi, with about 1500 Species currently described Kluyveromyces is a Genus of ascomycetous yeasts in the family Saccharomycetaceae. 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. ^[55]

Rehabituation to dairy products

Wiktionary has an entry for rehabituation.

For healthy individuals with Secondary lactose intolerance, it may be possible to train bacteria in the large intestine to break down lactose more effectively[2] 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. Lactase (LCT a part of the β-galactosidase family of Enzymes is a Glycoside hydrolase involved in the Hydrolysis

However, other studies have shown that lactase production does not seem to be induced by dairy/lactose consumption. Lactase (LCT a part of the β-galactosidase family of Enzymes is a Glycoside hydrolase involved in the Hydrolysis [3]

Nutritional concerns

Primary lactose intolerance

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). For a topic outline on this subject see List of basic Japan topics.

Secondary lactose intolerance

While secondary lactose intolerance does not inherently affect an individual's nutritional needs, according to mainstream media and "accepted" 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. Calcium (ˈkælsiəm is the Chemical element with the symbol Ca and Atomic number 20 Potassium (pəˈtæsiəm is a Chemical element. It has the symbol K (kalium from qalīy Atomic number 19 and Atomic mass 39 Vitamin A refers to a family of similarly shaped molecules the Retinoids. Vitamin D is a group of fat-soluble Prohormones, the two major forms of which are vitamin D2 (or Ergocalciferol) and vitamin D3 (or Consequently, in dairy consuming societies, dairy is often a main source of these nutrients; and, for lacto-vegetarians, a main source of vitamin B12. A lactovegetarian diet is a vegetarian diet which includes Dairy products such as Milk, Cheese, Yogurt, Butter, Cream Individuals who reduce or eliminate consumption of dairy must obtain these nutrients elsewhere. Asian populations for whom dairy is not part of their food culture do not present decreased health and sometimes present above average health, like Japan. For a topic outline on this subject see List of basic Japan topics.

Plant based milk substitutes are not naturally rich in calcium, potassium, or vitamins A or D (and, like all non-animal products, contain no vitamin B12). However, prominent brands are often voluntarily fortified with many of these nutrients, although one should read the label to be certain.

An increasing number of calcium-fortified breakfast foods, such as orange juice, bread, and dry cereal, have been appearing on supermarket shelves. Orange juice is a Fruit juice obtained by squeezing pressing or otherwise crushing the interior of an orange. Bread is a Staple food prepared by Baking a Dough of Flour and Water. A breakfast cereal (often simply called cereal is a packaged food product made from Cereal intended to be consumed as part of a Breakfast. 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. A dietitian (also 'dietician' though 'dietitian' is used consistently by professionals is an expert in Food and Nutrition.

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,^[56] so these infants do not benefit from being put on a lactose-free diet unless symptoms of lactose intolerance are severe and persistent. Gastroenteritis (also known as gastro, gastric flu, and stomach flu, although unrelated to Influenza) is Inflammation of the Rotavirus is a Genus of Double-stranded RNA virus in the family Reoviridae.

Congenital lactase deficiency

Congenital lactase deficiency, or CLD, is an autosomal recessive disorder which prevents the expression of lactase. An autosome is a non-sex Chromosome. It is an ordinarily paired type of chromosome that is the same in both Sexes of a species. ^[57] 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.

See also

• Gastroenterology
• Gluten intolerance
• Milk allergy
• Plant milk
• Soy cheese
• Sucrose intolerance

References

Footnotes

External links

• Great german website about lactose intolerance
• United States National Institutes of Health page regarding lactose intolerance
• Scientific American: African Adaptation to Digesting Milk Is "Strongest Signal of Selection Ever" (East African cattle herding communities rapidly and independently evolved ability to digest lactose)