I’ve heard about lactose intolerance. Is this a common problem with milk? Like milk allergy, lactose intolerance is usually an over-diagnosed or a self-diagnosed problem. Lactose, the sugar in both human and cow’s milk, is normally digested by the intestinal enzyme, lactase, which breaks the lactose down into glucose and galactose. Some infants, children, and adults are deficient in this intestinal enzyme and thus cannot absorb lactose. When the amount of lactose in the diet exceeds the supply of lactase in the cells of the intestinal lining, the undigested lactose travels down the intestines. There bacteria digest some of the lactose, but the rest ferment and are converted into the gas, carbon dioxide, which causes bloating , diarrhea, and abdominal pain, and to lactic acid, which accounts for the red, irritated, burn-like ring around the anus, especially noticeable in lactose-intolerant children. Other more subtle symptoms are: headaches, fatigue, and bad breath.
Lactose intolerance is rare in infants, but more common as people get older, so there is some biochemical basis for the idea that you outgrow your need for milk. There are degrees of lactose intolerance, depending on the supply of lactase in the gut. Some children and adults can tolerate one glass of milk, but not two or three; or they can drink milk with a meal, but not separately on an empty stomach. Many can tolerate yogurt and cheese, but not milk as a beverage. (The lactose in fermented yogurt is somewhat predigested.) Lactose intolerance is more common than allergy to the protein in milk. Allergic symptoms usually involve the skin and respiratory systems, whereas lactose intolerance is limited to abdominal symptoms. Lactose- intolerance is especially prevalent in Asians, Hispanics, and African-Americans. In fact, it is estimated that around three-fourths of the world’s population experience some degree of lactose intolerance.
Lactose intolerance may appear after the intestinal lining has been injured by allergy or infection. This is called secondary lactose intolerance, and it lasts only until the intestinal lining is healed. It is especially common in children after a diarrhea-producing viral illness and the reason for delaying the introduction of milk during the recovery stage.
If you are lactose-intolerant, try these strategies for getting the nutritional benefits of milk into your diet:
- Avoid lactose-containing dairy products for a couple weeks and then gradually increase the amount you consume, beginning with a tablespoon of milk and doubling the amount every few days until you reach your tolerance. Within a few weeks, lactose-indigestion can turn into digestion.
- Drink your milk in smaller more frequent servings.
- Drink reduced-lactose milk, such as Lactaid, or take a lactase capsule along with the milk.
- Drink or eat dairy products with meals rather than solo to give your intestines a better chance to digest the lactose. Anything that slows the transit of food through the intestines gives the lactase-containing cells more time to do their job.
- Some dairy products contain more lactose than others. Here’s a general guide, ranked from most to least in lactose content:
- skim milk
- lowfat milk
- whole milk
- ice cream
- cottage cheese
- cream cheese
- butter (none or negligible lactose)