Lactose is the most important carbohydrate in the milk of most species. It is found in the milk of mammals to the extent of approximately 2–8%. Lactose is therefore sometimes called milk sugar and is a disaccharide of glucose and galactose. It is usually prepared from whey, which is a liquid by-product in the manufacture of cheese. Upon concentration of the whey, crystalline lactose is deposited and it is the least sweet of all the natural sugars.
Lactose is used commercially in foods such as baby formulas, infant foods and confectionery. The fermentation of lactose to lactic acid by bacteria is responsible for the souring of milk. It is also widely used in pharmaceuticals as it is relatively inexpensive, non toxic and does not react with other ingredients. In the pharmaceutical industry, it is used as tablet filler and as a medium for growth of microorganisms. It is available as tablets, capsules and sachets.
Although lactose is potentially a rich source of energy, some people cannot digest lactose and suffer from Lactose Intolerance.
 Lactose Intolerance
Lactose intolerance is a problem caused by the digestive system. People with lactose intolerance may feel very uncomfortable when they digest milk products or other foods containing lactose. This is so because they lack the enzyme (lactase) that splits lactose into the simpler sugars, glucose and galactose. Lactose intolerance is more commonly seen in adults than infants because the primary lactase deficiency develops over time. The body begins to produce less and less lactase, though most people will not notice symptoms until they are much older. A large proportion of the population may suffer some degree of lactose intolerance as they grow older.
Lactose intolerance may also be caused due to injury to the small intestine or some digestive diseases. Researchers have found a gene linked to lactose intolerance. That is, it increases the likelihood of such people developing primary lactase deficiency because it has been passed on to them genetically (inherited from their parents).
Since lactose intolerant people cannot digest lactose, it stays in the intestine upon ingestion and is fermented. This causes symptoms of intestinal discomfort such as abdominal pain, bloating, cramps and diarrhea. Symptoms begin about 30 minutes to 2 hours after eating or drinking foods containing lactose. The severity of symptoms varies from person to person and depends on factors including age, ethnicity and the amount of lactose that a person can tolerate. Some people may suffer severe symptoms after consuming small amounts of lactose. Others may be able to tolerate small amounts of lactose such as milk in tea, or larger quantities spread over the day.
The treatment for lactose intolerance is mainly dietary and symptoms can be controlled by avoiding foods containing lactose. It is extremely rare for lactase to be totally absent – most people produce some lactase, so some milk products can be tolerated. The level of dietary control needed with lactose intolerance depends on how much lactose a person’s body can handle. Recent studies have shown that one serving of milk with a meal can be consumed by lactose intolerant people without experiencing symptoms. Foods like aged cheese (has less lactose) and yoghurt (has bacteria to digest lactose) are also well tolerated.
 Did You Know?
- Many processed foods like creamed or breaded vegetables; pancake mixes; packaged dried potato mixes; tomato and spaghetti sauce with cheese luncheon meats; sausage; frankfurters; some brands of egg substitutes and powdered eggs contain hidden amounts of Lactose.
- Between 30 and 50 million Americans are lactose intolerant and certain ethnic and racial populations are more affected than others. Up to 80 percent of African Americans, 80 to 100 percent of American Indians, and 90 to 100 percent of Asian Americans are lactose intolerant. The condition is least common among people of northern European descent.
 Lactase Supplements
Lactase supplements are available to help people digest foods that contain lactose. These should be taken before eating or drinking dairy products. The lactase supplements are available in both pill and liquid form.
 Lactose Reduced Products
Lactose-reduced milk and milk products are also available for most kinds of dairy products, including milk, cheese, and ice cream. This milk contains all of the nutrients found in regular milk. Special milk products such as Lacteeze or other "Lactose-free milk" are available in which the lactose is reduced by 99%. In some "lactose-reduced" milk products, lactose has been partially reduced. So, one can choose these products according to his tolerance for lactose.
A concern for both children and adults with lactose intolerance is getting enough calcium in a diet that includes little or no dairy products. Thus, while planning diets for lactose intolerant people, foods high in calcium such as dark, green leafy vegetables, like broccoli, tofu and fish like salmon, sardines should be included. Although these foods are high in calcium, the body cannot absorb it as easily as from milk.
Eating foods fortified with calcium, like certain cereals and orange juice, and taking calcium supplements also can help to reach the optimal calcium intake. Soy is another option as it has long been used as a dairy alternative. Soymilk does not contain lactose and is therefore suitable for lactose intolerant people. Even though lactose intolerance is common, it is not a threat to good health. A carefully chosen diet, with calcium supplements if the doctor or dietitian recommends them, is the key to reducing symptoms and managing lactose intolerance.
- List of Lactose-Free Foods
- Lactose Intolerance
- Lactose Intolerance: What you can eat?
- Dictionary: lactose
 Additional Information
More information on lactase supplements regarding their purchase can be obtained at websites such as:
- Hymie!'s Lactose Intolerance Headquarters
- Reduced lactose foods can be obtained at websites such as The Product Clearinghouse