No Good Data For or Against Taking Vitamins, Experts Say

But half of U.S. adults take at least one supplement, government task force notes

By Mary Elizabeth Dallas

Monday, November 11, 2013

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Dietary Supplements

MONDAY, Nov. 11 (HealthDay News) -- Even though millions of Americans pop a vitamin, mineral or multivitamin supplement every day, an influential government-appointed panel of experts says the jury is still out on whether they help boost health or not.
In its draft guidelines, the U.S. Preventive Services Task Force said that in some cases, certain supplements, such as beta carotene or vitamin E, may actually do more harm than good. Instead of focusing on supplements, they recommend that people focus on the health benefits of a well-balanced diet instead.
"In general, the Task Force found that there is not enough evidence to determine whether you can reduce your risk of cardiovascular disease or cancer by taking single or paired nutrients, or a multivitamin," Task Force Co-Chair Dr. Michael LeFevre said in a news release. "However, there were two major exceptions: beta carotene and vitamin E, both of which clearly do not help prevent these diseases."
Citing a lack of evidence, the panel concluded it could not recommend taking certain vitamins and minerals alone, together or in a multivitamin for the prevention of heart disease or cancer. The expert panel noted, however, it didn't have enough data to advise against taking most of these supplements, either.
The exceptions to that recommendation: beta carotene and vitamin E. In that case, the experts advised that people not use these supplements for the prevention of heart disease or cancer. Vitamin E supplements were found to have no disease-fighting benefit and beta carotene could actually be harmful, since it appears to boost the risk of lung cancer in people already at greater risk for this disease.
"Many people take dietary supplements to support their general health and wellness," panel member Dr. Wanda Nicholson said in the Task Force news release. "In the absence of clear evidence about the impact of most vitamins and multivitamins on cardiovascular disease and cancer, health care professionals should counsel their patients to eat a healthy, well-balanced diet that is rich in nutrients. They should also continue to consider the latest scientific research, their own experiences, and their patient's health history and preferences when having conversations about nutritional supplements."
The Council for Responsible Nutrition, which represents the vitamin supplement industry, had this to say about the Task Force's recommendation:
"As the researchers have indicated, there is limited evidence for multivitamins in preventing cancer or cardiovascular disease; however, we believe the paucity of clinical trial evidence should not be misinterpreted as a lack of benefit for the multivitamin," Duffy McKay, vice president of scientific and regulatory affairs at the council, said in a statement. "We know for sure that multivitamins can fill nutrient gaps, and as so many people are not even reaching the recommended dietary allowances for many nutrients, that's reason enough to add an affordable and convenient multivitamin to their diets."
The Task Force panel posted its draft recommendation on the use of vitamin, mineral and multivitamin supplements to prevent heart disease and cancer on its website on Monday. The evidence-based recommendations will be available for public comment until Dec. 9. The Task Force's evidence report is also published in the Nov. 12 online edition of the Annals of Internal Medicine.

SOURCE: U.S. Preventive Services Task Force, news release, Nov. 11, 2013; Nov. 11, 2013, statement, Council for Responsible Nutrition, Washington, D.C.

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