What is lactose intolerance ?
Lactose intolerance is the inability to digest the milk sugar lactose, causing intestinal problems arise. Young mammals are due to the lactase enzyme able to convert lactose into the monosaccharides glucose and galactose, which are then absorbed into the blood. The power will make this enzyme with the increasing age gradually, so most races (and other mammals) in adulthood are lactose intolerant. Adults from populations that have traditionally used their entire life milk can generally well tolerated lactose. Preventing reduced lactose tolerance varies from 5% in Northern Europe to over 90% in African and Asian countries.
Lactose intolerance is different from cow's milk allergy, one of the most common allergies. An allergy converts a protein into effect the immune system, and also a small amount thereof may lead to a life-threatening condition. This is not the case with an intolerance.
Symptoms of lactose intolerance
Lactose is a substance that contributes to serve a high osmotic value in the intestines and can, moreover, as a power source for certain kinds of bacteria. The first in the small intestine promotes the absorption of water, so that the content and the rate of transport is increased, with cramps (abdominal pain), nausea, and 'rumbling' as tactile symptoms. In the colon, followed by other issues: certain bacteria ferment the lactose which carbon dioxide, hydrogen and release organic acids. This also causes abdominal pain, flatulence, and in severe cases diarrhea, which is watery thin, sour smell, and sometimes foaming and greenish in color.
How to diagnose lactose intolerance
There are various methods to determine lactose intolerance:
Provocation Test: here a few days is a lactose-free diet followed, then for example a glass of milk or a lactose solution to drink. If the above symptoms occur, there may be lactose intolerant.
Hydrogen test: after several days lactose free to have eaten a patient should drink a solution containing 50 grams of lactose. Is then measured how much hydrogen patient exhale for two to three hours. Hydrogen is secreted by intestinal bacteria that breaks down lactose if not done by the enzyme lactase. This is the standard test for the detection of lactose intolerance. The test is positive at 20 ppm hydrogen or more. In approximately one-fifth of the patients, this test is still negative, because their intestinal flora does not form hydrogen from lactose, but methane.
Test Acidity: the pH of the stool is measured. Sour stool may indicate lactose intolerance. This method is applied in particular in children.
Gentest: recently a genetic test available that lactose intolerance can determine with some mucus.
Blood Sugar Test: here the glucose content is measured in the blood after exposure to lactose. If this after one to two hours rises less than 10 mg / dl (0.55 mmol / dl) when exposed to 50 g of lactose is the non-reacted and there is lactose intolerance (or diabetes mellitus).
Test fabric: a biopsy is tested for lactase or mRNA. This rather drastic method is rarely used.
Genetics
Only Europeans seem to be able to digest lactose in adulthood majority, this is also known as lactase persistence. But also in Europe, according to estimates, 10 to 15% of all people are lactose intolerant. Both appear to be able to be fully explained by a mutation near the gene for lactase. Approximately 60-80% of people with lactose intolerance also struggling with Fructose malabsorption.
Babies at birth construction to make enough lactase to digest with the lactose in milk. It is for man actually quite common that the lactase production from the age of a few years continuously decreasing since then no lactose longer need to be digested. The age at which this happens depends on the ethnicity: for example, among mestizos in Peru are 30-55% of children lactose intolerent for the fourth year for Northern Europeans and Chinese, this is approximately 6 and 30% respectively. In recent centuries, Europeans (and their descendants, the Americans and Australians) increasing milk to consume, so that most of them now produce lactase throughout their lives. As a result, lactose intolerance condition as seen in these countries, even though it actually is the natural state.
From the DNA of the Neanderthal, which has been mapped since February 2009, indicates that the human species was lactose intolerant.
Other causes of lactose intolerance
Although lactose intolerance (to some extent), so it is a normal state, it can also special causes for it. There is a congenital defect which a newborn does not produce the enzyme lactase. This is a very rare condition. In addition, there is a further group of conditions that lead to secondary lactose intolerance, for example, by surgical removal or radiation treatment of the small intestine, by the intestinal parasites (eg. Giardia lamblia), viruses (eg. Rotavirus), fungi, (e.g. Candida albicans) or after a period of malnutrition.