People who believe they cannot digest even a small amount of milk or dairy products may be able to tolerate more than they think, according to a study.
Researchers at the Minneapolis Veterans Affairs Medical Center gave 8 ounces of milk a day to 30 people who believed they were severely lactose intolerant - in other words, unable to properly digest the sugar in milk called lactose.
Nine of the people turned out not to be lactose intolerant at all. The 21 others were lactose intolerant but still could handle a cup or less of milk a day with no discernible symptoms, such as bloating, diarrhea or abdominal pain. The study ran for two weeks and will appear in today’s issue of the New England Journal of Medicine.
“A fairly large fraction of people are under the delusion that if they smell milk they will get symptoms,” said Dr. Michael Levitt, one of the researchers. “But virtually everyone can take a cup of milk … It’s not the problem people think it is.”
To break down lactose, the body needs the enzyme lactase. But about 25 percent of Americans - including most people of African, Asian and Mediterranean descent - lose the enzyme in their 20s or 30s.
The typical test for lactose intolerance gives someone the equivalent of a quart of milk, Levitt said. But the average person doesn’t consume that much in one sitting, he said. So even people who test as lactose intolerant may be able to consume some dairy products. Consuming small amounts of dairy products is also a way to save money on milk that has been treated with lactase, which is more expensive, Levitt said.
In recent years, a $160 million-a-year industry has developed in products for the lactose intolerant, such as specially treated milk and drops or pills to take before eating cheese or ice cream.
“We agree that those people who do not experience symptoms should not use a dietary supplement,” said Robert Kniffin, company spokesman for Johnson & Johnson, which markets the product Lactaid through McNeil Consumer Products of Fort Washington, Pa. Lactaid is the market leader in the field, Kniffin said.
Kniffin said the company believes doctors and patients “will have to reach their own conclusion about how to use these new data.”
The study show that “just because someone is a maldigester doesn’t mean they need to stay away from dairy products,” said Barbara Baron, a dietitian for the American Dairy Association and Dairy Council. “It’s not an all-or-nothing response. Most people can tolerate dairy foods in typical serving sizes.”