(Reuters Health) - Taking multivitamins and minerals does not reduce the risk of cardiovascular disease or associated deaths, according to a new review of existing research.
“There is no scientific evidence that (these) supplements promote cardiovascular health,” lead author Dr. Joonseok Kim from University of Alabama at Birmingham told Reuters Health by email. “We hope that our paper helps to settle the debate” on the use of multivitamins and minerals (MVM) for cardiovascular disease prevention.
Americans spent an estimated $36.1 billion on vitamins and nutritional supplements in 2017, and many believe that MVM supplements maintain and promote health by preventing various diseases, including cardiovascular disease. Most large-scale studies, however, have found no such benefit.
Kim’s team pooled evidence from 18 studies with more than 2 million participants to investigate associations between MVM supplementation and various cardiovascular problems, including coronary heart disease and stroke.
Use of MVM supplements was not associated with the risk of death from cardiovascular disease or coronary heart disease, or stroke incidence or deaths, according to the report in Circulation: Cardiovascular Quality and Outcomes.
MVM supplements were associated with a slightly lower risk of developing coronary heart disease, but this difference was observed only in studies that did not account for fruit and vegetable intake and in studies conducted outside the U.S. The studies done in the U.S., and those that did factor in diet, found no statistically meaningful benefit from MVM supplements in preventing heart disease.
The results were consistent when researchers adjusted for other factors, such as follow-up duration, age, sex, physical activity, and so on.
“We learned from previous experiences that it is immensely difficult to influence the public when there is a strong preconception and commercial profits at stake,” Kim noted. “However, I believe healthcare professionals and researchers now have the evidence to educate the public with correct information and focus on more pressing questions for effective CVD prevention,” he said.
“I would like to encourage people to discuss the use of MVM supplements with their physicians and reallocate their resources to something that is proven to improve cardiovascular outcomes, such as fruit and vegetable intake and exercise.”
Dr. Susanne Rautiainen from Karolinska Institutet in Stockholm, who has extensively studied the use of MVM and disease prevention but was not involved in the review, told Reuters Health, “Hopefully the results influence physicians to not recommend multivitamins to their patients that are apparently healthy.”
The research community has been “quite active for a long time informing about the no associations among healthy populations, but still the sales of dietary supplements continue to increase, with multivitamin supplements among the most popular ones. But we will continue our work informing the society about the right facts,” she said in an email.
“This systematic review mainly included healthy populations, meaning that if you consider yourself healthy with no history of disease and a well-balanced diet characterized by high intakes of fruits and vegetables, whole grains, legumes, nuts, and fish, there is no reason to spend money on multivitamin supplements.”
Very little is known about how multivitamin use affects populations with a previous history of cardiovascular disease, older populations, and those with poor baseline nutritional status, for example, she noted. “But based on the research done so far, there is no reason to take a multivitamin to reduce your risk of developing CVD.”
On the other hand, notes Dr. Jeffrey B. Blumberg of the Jean Mayer USDA Human Nutrition Research Center on Aging at the Friedman School of Nutrition Science and Policy of Tufts University in Boston, multivitamins and minerals may still serve some purpose.
“It is interesting to me that questions about MVM and other nutrient supplements always seems focused on the medical model of preventing or treating disease (something which dietary supplements are not allowed to claim per FDA/FTC regulations), rather than on whether they effectively and/or efficiently do what they claim to do, i.e., supplement the diet with essential vitamins and minerals that have been found to be ‘underconsumed’ (according to the 2015-2020 Dietary Guidelines for Americans) . . . in many Americans,” he said in an email.
For example, he noted, 90 percent of people in the U.S. fail to meet the Estimated Average Requirement for potassium, vitamins D and E and choline.
“The inadequate intake of these micronutrients creates a ‘hidden hunger’ that could be partly addressed by supplements like MVM and correct the associated less-than-optimal daily structure/function of our cells and physiological systems,” said Blumberg, who wasn’t involved with the review.