WEDNESDAY, Feb. 24 (HealthDay News) - Many people who think they're lactose intolerant may not be.
This suggestion, released Wednesday in a U.S. National Institutes of Health draft consensus statement, could pave the way for more people to eat more dairy products, thus helping to ensure they get adequate nutrition in their diet.
Not enough data is available to estimate the prevalence of true lactose intolerance in the United States, the report stated, but it's likely the numbers are lower than those reported, said Natalie J. Miller, a member of the panel that issued the draft statement and a graduate student at the University of Pennsylvania School of Veterinary Medicine, at a Wednesday teleconference.
People with lactose intolerance usually are told to avoid milk and milk-containing products, but this can deprive them of needed nutrients, particularly calcium and vitamin D.
"Particularly in children and adolescents, it's very difficult for them to receive enough calcium and vitamin D if they avoid diary completely. The same thing may hold true for adults," said Dr. Frederick J. Suchy, chairman of the conference preceding the statement and professor and chief of pediatric hepatology at Mount Sinai School of Medicine in New York City.
"Vitamin D and calcium have important effects, for certain for bone health, and may have implications in other areas such as cardiovascular health, hypertension and maybe even colon cancer," he said.
Lactose is a sugar found in both human and cow's milk.
"In order to be absorbed as a nutrient, lactose has to be digested by lactase, an enzyme present in the lining of the small intestine," Suchy explained. "It's well recognized that during the period of suckling in the infant, levels of lactase in the intestine are at their highest in order to be able to digest and absorb an important food source."
By age of 3 or 4, however, lactase production usually decreases, and most people become "lactase nonpersisters."
"The majority of the world's population, after weaning and gradually over childhood, lose lactose activity," Suchy said. "It's a normal state. Only those people that are largely from northern European descent have retained lactase and have the ability to ingest and process lactose later in life."
But even most "nonpersisters" aren't really intolerant to lactose and could consume more dairy products.
It's first important to distinguish whether symptoms attributed to lactose intolerance -- diarrhea, abdominal pain, bloating and flatulence -- result from another, potentially serious gastrointestinal condition, such as irritable bowel syndrome or celiac disease.
But, said Suchy, even "if it is a problem with lactose, there may be strategies to cope with that."
Right now, when lactose intolerance is suspected, "the reflex response oftentimes is to tell the patient to stop taking dairy products completely," Suchy said. "There may be some patients where that has to be done and whatever nutritional deficiencies could be made up with supplements."
But for others, alternative strategies like taking small amounts of milk throughout the day or with meals or including yogurt and hard cheeses, especially low-fat hard cheeses, in the diet might be tolerable.
"This is not an allergic condition where if you take a little bit of milk you get sick. That's quite rare," noted Dr. Marshall A. Wolf, a panel member and professor of medicine at Harvard Medical School in Boston. "This is a quantitative condition and most people, even those with malabsorption, can take a certain amount of milk products without any symptoms, and there is some evidence to suggest that if you take milk products on a regular basis, you can build up your tolerance for milk."
Visit the U.S. Department of Agriculture for more on optimal nutrition, including sources of calcium and vitamin D.