“With the exception of a rare inherited disorder in which infants are born without lactase, infants have sufficiently high levels of lactase for normal digestion. However, lactase activity declines with weaning, and the degree of lactose intolerance is different amongst different ethnic groups.
Lactose maldigestion is usually worse amongst Asians. In Caucasians and Europeans, lactose maldigestion is far less common.
In addition to primary lactose intolerance, lactose intolerance can be secondary to diseases or conditions e.g., inflammatory bowel disease such as Crohn’s disease or celiac disease, gastrointestinal surgery, and certain medications, that injure the intestinal mucosa where lactase is expressed. The good news is that lactose digestion improves once the underlying causative factor is corrected.
Lactose intolerance is far less prevalent than commonly believed. Many factors unrelated to lactose, including strong beliefs, can contribute to this condition. Self-diagnosis of lactose intolerance is a bad idea because it could lead to unnecessary dietary restrictions, expense, nutritional shortcomings, and failure to detect or treat a more serious gastrointestinal disorder.
People with real or perceived lactose intolerance may limit their consumption of dairy foods unnecessarily and jeopardize their intake of calcium and other essential nutrients. A low intake of calcium is associated with increased risk of osteoporosis (porous bones), hypertension, and colon cancer.
With the exception of the few individuals who are sensitive to even very small amounts of lactose, avoiding all lactose is neither necessary nor recommended because some lactase is still being produced.
Here are some strategies for including milk and other dairy foods in your diet without developing symptoms:
1. Initially, consume small servings of lactose-containing foods such as milk (e.g., 1⁄2 cup). Gradually increase the serving size until symptoms begin to appear, then back off.
2. Consume lactose with a meal or other foods (e.g., milk with cereal) to improve tolerance.
3. Adjust the type of dairy food. Whole milk may be tolerated better than low- fat milk, and chocolate milk may be tolerated better than unflavored milk. Many cheeses (e.g., Cheddar, Swiss, Parmesan) contain considerably less lactose than does milk. Aged cheeses generally have negligible amounts of lactose. Yogurts with live, active cultures are another option; these bacteria will digest lactose. Sweet acidophilus milk, yogurt milk, and other nonfermented dairy foods may be tolerated better than regular milk by lactose maldigestors. However, factors such as the strain of bacteria used may influence tolerance to these dairy foods.
4. Lactose-hydrolyzed dairy foods and/or commercial enzyme preparations (e.g., lactase capsules, chewable tablets, solutions) are another option. Lactose- reduced (70 percent less lactose) and lactose-free (99.9 percent less lactose) milks are available, although at a higher cost than regular milk.
By testing the upper limit, then reducing it back to an acceptable level means that Lactose maldigestion need not be an impediment to meeting the needs for calcium and other essential nutrients provided by milk and other dairy foods.