Lactose is the sugar found in milk. Many people, as they grow older, are unable to digest this sugar because they lose the ability to produce the enzyme lactase in the intestinal tract. This enzyme is essential to permit the digestion of lactose and its absorption into the bloodstream. This problem is called lactose intolerance.
When the undigested lactose passes down the intestine into the lower digestive tract, the bacteria normally present there ferment it. This fermentation results in the production of gas and can cause diarrhea.
Many intestinal infections can produce temporary lactase deficiency, but for most people the problem is the permanent reduction in the amount of this enzyme because of aging. The enzyme loss is frequently partial, and the amount remaining varies widely from person to person. Accordingly, the amount of exposure to milk and milk products necessary to produce symptoms varies among individuals.
Important Points in Treatment
Symptoms can be managed in two ways. The first way is to reduce milk and milk products in the diet to levels that are too low to produce symptoms. The severity of the milk-free diet needed varies from person to person with the degree of deficiency of the enzyme lactase. Therefore, trial and error may be necessary to figure out what items to cut from any individual’s customary diet. Milk products are hidden in many processed foods, sauces, and breads and other baked goods. Often there are times when avoiding milk products is difficult if not impossible.
Not all milk products contain lactose in quantities sufficient to produce symptoms. In hard cheeses such as Swiss or Parmesan, lactose is consumed in the preparation of the cheese, and these products do not produce symptoms. Soft cheeses such as brie may contain more lactose. The fermentation of yogurt also consumes the lactose, converting it into sugars that are readily absorbed in the intestinal tract. Yogurt generally does not produce symptoms of lactose intolerance.
The second way to manage lactose intolerance is to add the missing enzyme lactase to milk to predigest the lactose and permit its absorption. This milk may be used for cooking as well as drinking. Also, tablets containing lactase can be taken at the time of eating food that contains milk. This may be helpful when faced with birthday ice cream and cake or a restaurant meal.
Caregivers should be aware that traditional nutritional supplements for the ailing individual including eggnogs, milk shakes, custards, and the like may contain substantial lactose and may cause symptoms. Lactose content of these preparations is usually listed on the label.
Notify Our Office If ...
You have diarrhea that does not resolve. Symptoms of lactose intolerance may result from an increase in the amount of lactose ingested. Symptoms may also result from disease in the intestinal tract that causes a decrease in the amount of enzyme available. A sick person may not be able to continue to tolerate milk and milk products in customary amounts.