A condition in which a person cannot digest lactose because lactase is absent in the intestine or because of an allergy to milk, causing diarrhoea.
The absence of an enzyme that is needed to digest milk sugar.
Inability to digest lactose due to decreased (or absence of) lactase activity. In the absence of lactase, lactose is not hydrolyzed (digested) and acts as an osmotic agent stimulating peristalsis with the clinical symptoms of flatulence, bloating, cramps, and diarrhea. Current evidence indicates that lactose intolerance is more common than lactose tolerance. Notable exceptions to these observations are Caucasians of Scandinavian or Northern European background. Less than 5% of these populations has lactose intolerance, and they traditionally consume diets containing large amounts of milk and milk products.
Lactose intolerance occurs when there is insufficient production of the enzyme lactase to digest the simple sugar lactose. When lactose goes partially or largely unabsorbed, several adverse reactions occur. One effect of lactose intolerance is diarrhea. Since lactose is a hydrophilic molecule, if unabsorbed it can pull water into the gastrointestinal tract producing an osmotic diarrhea. Furthermore, the unabsorbed lactose can be fermented by bacteria in the colon, which produces gas. Together, these effects also produce symptoms of bloating, cramping, and abdominal pain. Athletes with lactose intolerance must be careful not to consume milk-based beverages during competition.
Lactose intolerance is the inability of the body to digest lactose, a carbohydrate found in milk and most dairy products. It is caused by a deficiency in the enzyme lactase, which is responsible for breaking down lactose. Lactose intolerance may be classified as either primary or secondary. Primary lactose intolerance is genetic and develops around 2-3 years of age, whereas secondary lactose intolerance arises as a result of another medical condition (e.g., cystic fibrosis, chemotherapy, Whipple’s disease) or unknown causes. Most often, lactose intolerance results from low lactase activity, not the complete absence of lactase. Congenital lactose intolerance, characterized by a complete absence of lactase activity, is extremely rare. Diagnosis of lactose intolerance is made by a physician either through lactose intolerance tests, breath hydrogen tests, biopsy of the small intestine, or clinical observations and interviews.
A type of digestive disorder involving inability to break down milk sugar (lactose) into forms that can be used by the body, generally because of shortage of the enzyme lactase; also called lactase deficiency. Sometimes lack of lactase results from disorders or injuries affecting the intestinal tract, but in many cases, especially after age two, children’s bodies begin to produce less lactase. Common symptoms of indigestion of lactose are nausea, cramps, bloating, gas, and diarrhea, about 30 to 120 minutes after eating foods containing lactose. The problem is especially common among people of Black African, Asian, or Jewish ancestry, and less common among those of Caucasian background from northern Europe. Lactose intolerance is in itself not a danger, but because calcium is so important to growth and repair of bones, especially in the growing years, it is necessary to be sure that children (and adults) get anough calcium from other sources, such as those in Calcium and Lactose in Common Foods.
Disorder, due to a defect or deficiency of the enzyme lactase, resulting in an inability to digest lactose and symptoms of bloating, flatulence, abdominal discomfort, nausea, and diarrhea on ingestion of milk and milk products.
The inability to digest lactose, the predominant sugar found in milk and other dairy products. Lactose intolerance is due to a shortage of the enzyme lactase, which breaks down lactose so it can be absorbed by the body. The symptoms of lactose intolerance develop 30 minutes to 2 hours after consuming dairy products. They include nausea, bloating, gas, and diarrhea. The severity of symptoms and the amount of lactose that can be consumed before developing symptoms differs among individuals. A diagnosis of lactose intolerance is suggested by the appearance of characteristic symptoms after ingesting lactose and the resolution of symptoms by a lactose-free diet. Tests such as the lactose intolerance test and the hydrogen breath test or measuring stool acidity can be used to confirm a diagnosis. Lactose intolerance is treated by eliminating or reducing the amount of dairy foods in the diet. Many people can continue to enjoy dairy products if they consume them in small amounts or along with other foods. Others can take advantage of products such as lactose-reduced milk or tablets that help digest lactose. Because milk and dairy products are a rich source of calcium, doctors recommend that people who are lactose- intolerant take calcium supplements and consume other foods that are high in calcium but low in lactose.
This is due to lack in the intestine of the enzyme known as lactase, which is responsible for the digestion of lactose, the sugar in milk. In people with lactose intolerance, drinking milk or eating milk-containing products causes nausea, a sensation of bloating or distension in the gut, abdominal pain and diarrhoea. (Similar disturbances after taking milk may also occur in those who have an allergy to milk protein). Treatment is by means of a low-lactose diet, achieved by avoiding fresh or powdered milk and milk puddings. Many can tolerate fermented milk products, as well as the small amounts of milk used in baking and added to margarine and other food products. However, infants may have to be fed exclusively on a lactose-free formula, as even breast milk may produce symptoms.
An inability to digest milk and some dairy products, leading to abdominal bloating, cramping, and diarrhea. The intolerance may be congenital or may begin in childhood, adolescence, or young adulthood.
The inability to completely digest the milk sugar lactose.
An inability to digest lactose because the digestive system does not produce enough lactase.