Lactose Intolerance Rates Lower Than Previously Thought

A new study suggests that the prevalence of lactose intolerance among the population may be far lower than previously estimated.

Researchers at the U.S. Department of Agriculture/Agricultural Research Service (USDA/ARS; Washington, DC, USA) used data from a U.S. national sample to determine the prevalence of self-reported lactose intolerance among European American (EA), African American (AA), and Hispanic American (HA) adults. To do so, a representative sample of randomly selected telephone numbers were called from a computer-assisted telephone interviewing facility. Interviews were completed by a total of 1,084 respondents between the ages of 19 and 70 years, which included 486 EAs, 355 AAs, and 243 HAs. The response rate was 24.2%, and the cooperation rate was 34.2%.

According to the researchers, previous estimates of lactose intolerance incidence--which were based on the incidence of lactose maldigestion, or low lactase activity in the gut --may be overestimated by wide margins. While these previous studies had found lactose maldigestion to occur in approximately 15% of European Americans, 50% of Mexican Americans, and 80% of African Americans, the new study shows that the age-adjusted lactose-intolerance prevalence estimates were 7.72%, 19.50%, and 10.05%, respectively. Total crude and age-adjusted self-reported lactose-intolerance prevalence rates were 13.38% and 12.04%, respectively. The study was published in the September-October 2009 issue of Nutrition Today.

"There's so much confusion surrounding lactose intolerance. By getting a better handle on the true number of people who deal with this condition every day, the nutrition community can be better equipped to educate and provide dietary guidance for Americans, including strategies to help meet dairy food recommendations for those who self-report lactose intolerance,” said lead author Theresa Nicklas, Dr.PH, of the USDA/ARS Children's Nutrition Research Center at Baylor College of Medicine (Houston, TX, USA).

"Those with lactose intolerance are often relieved to know they can still enjoy the great taste and health benefits of dairy if they follow certain strategies," added study coauthor Orsolya Palacios, Ph.D., R.D. "The symptoms of lactose intolerance vary greatly for each individual, and there are options in the dairy case that allow almost everyone to take advantage of the health benefits provided by the recommended three daily servings of dairy foods.”

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U.S. Department of Agriculture/Agricultural Research Service

Baylor College of Medicine