Lactose intolerance is the inability to digest the main sugar found in milk and other dairy products. This is caused by a deficiency of lactase, the enzyme responsible for metabolizing lactose in the small intestines. The prevalence of lactose intolerance in adults varies from less than 5 percent to almost 100 percent between different populations of the world according to research published in the Scandinavian Journal of Gastroenterology. The lowest prevalence has been found in northwestern Europe, around the North Sea, and the highest prevalence in the Asians and American Indians.
Lactose intolerance is different than milk allergy since the latter is related to the proteins in milk rather than lactose.
Symptoms and Causes
Although reduced levels of lactase could result in improper absorption of lactose, only people with low lactase level and exhibiting the common symptoms would be properly considered as lactose intolerant. According to the Mayo Clinic, most people with lactase deficiencies do not display any signs or symptoms. In lactose intolerant adults, the lactose is fermented and metabolized by bacteria in the colon to produce gas and short chain fatty acids. This results in abdominal cramps, bloating, diarrhea, flatulence and nausea. The severity of symptoms largely depends on how quickly the lactase available in the digestive system is used up.
Diagnosis & Tests
Lactose intolerance should be suspected in people with abdominal symptoms—such as cramps and bloating—after consuming milk and other dairy products. The initial diagnosis of lactose intolerance can be very simple—it’s a matter of eliminating certain foods from the diet to see if symptoms improve, and then reintroducing the same foods into the the diet again to see if those symptoms would come back. Most patients do not need referral to a specialist or diagnostic laboratory tests. However, the symptoms for lactose intolerance can overlap with other gastrointestinal problems such as irritable bowel syndrome and Crohn’s Disease. A hydrogen breath test is an objective, non-invasive, inexpensive and easy-to-perform test that can be used to confirm initial diagnosis. A properly administered breath test can help patients determine whether they need to cut back on milk and dairy products, according to research published in the World Journal of Gastroenterology.
Treatments & Medications
Over-the-counter pills or drops that contain lactase can be taken before meals to help alleviate or eliminate symptoms. Though, according to the Mayo Clinic, not everyone with lactose intolerance is helped by these products. Adults who are lactose intolerant can ultimately recondition their digestive system to tolerate up to 250 milliliters of milk—about a glass—if they drink milk in gradually increasing portions. According to a 21-day intervention study conducted in 2000, most people who do this will experience minimal or no discomfort.
Lactose intolerance can be treated with simple dietary measures. The most straightforward way would be to reduce the amount of milk or daily products in their diet. Also, it may help to divide daily milk and dairy products into several small portions and to take it with other foods. Processed dairy such as yogurt and cheeses are usually better tolerated, because the lactose is partially metabolized by bacteria during their preparation.