Analysis of data from the third National Health and Nutrition Examination Survey (NHANES III) only showed the benefits for multivitamin/minerals (MVM) supplements when women took them for more than three years, according to findings published in the Journal of Nutrition.
The lack of an effect in men is consistent with other studies, including the Physician’s Health Study II, wrote the authors, led by Dr Regan Bailey from the ODS. PHS II is the only large-scale (with 14,641 male US physicians), randomized, double-blind, placebo-controlled trial investigating the long-term effects of a common multivitamin in the prevention of chronic disease.
(While no effects were found for CVD risk, an 8% reduction in cancer was reported by the PHS II researchers.)
Filling nutrient gaps and maybe more
Commenting on the study’s findings, Jim Griffiths, PhD, VP of scientific & international affairs for the Council for Responsible Nutrition, told NutraIngredients-USA: “Although multivitamin-multimineral supplements are taken primarily to fill nutrition gaps, it is not uncommon for researchers to examine the affect that supplement use may or may not have on chronic disease end-points.
“In this case, researchers at the NIH Office of Dietary Supplements (ODS), National Cancer Institute (NCI) and the National Center for Health Statistics report that they did see an association between these common daily dietary supplement products that were used for greater than 3 years and reduced cardio vascular disease (CVD) mortality risk for women when appropriately controlled.
“The researchers further conclude that the findings suggest that longer term use of these multivitamin-multimineral products may have a protective relation, at least in US women with a lack of history of CVD.”
Dr Regan and her co-workers analyzed data from 8,678 people aged forty and over. Data showed that, over an average follow-up period of 18 years, there was no overall association between users and non-user of the multivitamin and mineral supplements.
However, when they focused the data on length of supplementation, the risk of cardiovascular disease was reduced by 35% in people who used MVM for over three years, compared with non-users, with this association being driven by women.
Indeed, the cardiovascular risk reduction was greater than 35% for women in all of the different statistical models used by the researchers.
It was not all doom and gloom for the men, however, with a reduction in CVD risk observed for male multivitamin users who took the products for between one and three years. “[B]ecause of the smaller sample sizes and number of deaths (n = 5) in this group, this result should be interpreted cautiously,” said Dr Regan and her co-authors.
A distinction was also observed between multivitamin-mineral (MVMs) products and multivitamins (MVs).
“The main difference between MVMs and MVs is the presence of minerals,” explained the researchers. “A typical MVM has minerals, including calcium (generally about 150 mg only), magnesium, zinc, phosphorus, manganese, and copper, and, depending on the formulation type, may or may not contain iron, selenium, iodine, chromium, or molybdenum.
“It is not possible to separately estimate the effect of any individual nutrient, nutrient combinations, or specific amounts of nutrients in this analysis. However, we can speculate that minerals or certain vitamins not always found in MV formulations (e.g., vitamin D) may help explain the differential effect of MVM products on CVD mortality.
“For example, meta-analyses have found magnesium intake to be inversely associated with risk of strokes and reduced risk of ischemic heart disease and its mortality. Another meta-analysis demonstrated a nonsignificant protective association of vitamin D with CVD mortality.
“We hope this work serves to highlight the importance of defining the type and constituents of dietary supplements used in future research.”
Source: Journal of Nutrition
Published online ahead of print, doi:10.3945/jn.114.204743
“Multivitamin-Mineral Use Is Associated with Reduced Risk of Cardiovascular Disease Mortality among Women in the United States”
Authors: R.L. Bailey, T.H. Fakhouri, Y. Park, et al.