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Evidence is lacking for or against multivitamins to prevent heart disease or cancer, US task force says

BMJ 2013; 347 doi: http://dx.doi.org/10.1136/bmj.f6840 (Published 13 November 2013) Cite this as: BMJ 2013;347:f6840
  1. Michael McCarthy
  1. 1Seattle

The evidence is insufficient to tell whether taking multivitamins to prevent cardiovascular disease or cancer is beneficial or harmful, the US Preventive Services Task Force has concluded in a draft report released Tuesday 12 November.1

The task force also found that there wasn’t enough evidence to say whether products that provided one or pairs of vitamins and minerals were either helpful or harmful in the primary prevention of cardiovascular disease or cancer.

However, it did conclude that taking either vitamin E or β carotene did not help prevent cardiovascular disease or cancer and further that β carotene supplements may actually increase the risk of developing lung cancer in people who were already at high risk of the disease, such as heavy smokers.

About half of US adults report taking at least one dietary supplement, and a third report taking a multivitamin and multimineral supplement. It is estimated that Americans spend more than $28bn (₤17.5bn; $21bn) a year on such dietary supplements.

Most people take supplements in the hope of preventing disease or slowing an existing disease, the task force said, and many healthcare providers recommend dietary supplements to their patients.

The task force’s findings apply to healthy adults who do not have known nutritional deficiencies and not to children; pregnant women, who should take supplements containing folic acid; chronically ill people; and people whose nutrition may be poor because of poverty, where they live, dietary restrictions, or a disorder that impairs absorption of nutrients.

The findings also did not apply to high dose regimens, because of known harms, the task force said. “Both vitamins A and D have known harms at doses exceeding the tolerable upper intake level, and the potential for harm from other supplements at very high doses should be carefully considered.”

The draft recommendations will be available for comment until 9 December, 2013.

Notes

Cite this as: BMJ 2013;347:f6840

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