For a long time, cow's milk has been known to be a source of unpleasant symptoms such as gastric upsets and urticaria (formation of groups of acne buttons on several places on the body). The reactions are due to lactose intolerance or allergy to milk protein. In babies, both food reactions can co-exist. Milk is a baby's first foreign protein source, and is a very important source of nutrients for babies; thus, it cannot be removed easily from infant diets.

Lactose intolerance is the inability to digest significant amounts of lactose, the predominant sugar of milk. This inability results from a shortage of the enzyme lactase, which is normally produced by the cells that line the small intestine. Lactase breaks down milk sugar into simpler forms that can then be absorbed into the bloodstream. When there is not enough lactase to digest the amount of lactose consumed, the results, although not usually dangerous, may be very distressing. While not all persons deficient in lactase have symptoms, those who do are considered to be lactose intolerant.

Although milk and foods made from milk are the only natural sources, lactose is often added to prepared foods. People with very low tolerance for lactose should know about the many food products that may contain even small amounts of lactose, such as

• bread and other baked goods
• processed breakfast cereals
• instant potatoes, soups, and breakfast drinks
• margarine
• lunch meats (other than kosher)
• salad dressings
• candies and other snacks
• mixes for pancakes, biscuits, and cookies
• powdered meal-replacement supplements

Common symptoms include nausea, cramps, bloating, gas, and diarrhea, which begin about 30 minutes to 2 hours after eating or drinking foods containing lactose. The severity of symptoms varies depending on the amount of lactose each individual can tolerate.

Some causes of lactose intolerance are well known. For instance, certain digestive diseases and injuries to the small intestine can reduce the amount of enzymes produced. In rare cases, children are born without the ability to produce lactase. For most people, though, lactase deficiency is a condition that develops naturally over time. After about the age of 2 years, the body begins to produce less lactase. However, many people may not experience symptoms until they are much older.

Common symptoms include nausea, cramps, bloating, gas, and diarrhoea, which begin about 30 minutes to 2 hours after eating or drinking foods containing lactose. The severity of symptoms varies depending on the amount of lactose each individual can tolerate.

Tips

• Smart shoppers learn to read food labels with care, looking not only for milk and lactose among the contents, but also for such words as whey, curds, milk by-products, dry milk solids, and non-fat dry milk powder . If any of these are listed on a label, the product contains lactose.
• Lactose is used as the base for more than 20 percent of prescription drugs and about 6 percent of over-the-counter medicines. Many types of birth control pills, for example, contain lactose, as do some tablets for stomach acid and gas. However, these products typically affect only people with severe lactose intolerance. Therefore people with high lactose intolerance should also read the prescriptions of drugs.

Geri