SHOULD YOU TAKE A MULTIVITAMIN FOR HEALTH? Most are chock full of nutrients: You can find 50 to 150 percent of the US Recommended Dietary Allowance (RDA) for all vitamins, including A, C, D, E, B2, B6, B12, and folic acid. Of course, there are variations (including multivitamins targeting specific groups such as females, males, younger, and older populations, respectively). Some also contain minerals such as calcium and iron.
Do you take a multivitamin? Many do, recognizing the potential health benefits of the component vitamins, relative safety in reasonable disease, and availability of low-cost multivitamins.
Today we look at the efficacy of multivitamins for those not at risk of vitamin deficiency. We will not look at vitamin use for those with poor-quality diets (including those low in fruits and vegetables), an alcohol use disorder, a vegan diet, a history of bariatric surgery, those with some inborn errors of metabolism, or those receiving dialysis or intravenous nutrition.
Do we have evidence that multivitamins and mineral supplements add benefits if you have a healthy, balanced diet? No, we have not established that these supplements improve health. Let’s examine some studies examining the relationship between supplement use and health.
First, a 2021 evidence review for the United States Preventative Services Task Force (USPSTF) included 84 studies. Vitamin and mineral supplementation was not associated with cardiovascular disease or early death improvements. There appeared to be one upside to taking a multivitamin:
The review for the USPSTF showed a small benefit for cancer incidence with multivitamin use. Evidence for the benefits of other supplements appeared to be “equivocal, minimal, or absent. Limited evidence suggests some supplements may be associated with a higher risk of serious harm (hip fracture [vitamin A], hemorrhagic stroke [vitamin E], and kidney stones [vitamin C, calcium]).
While this review discovered no other benefits from multivitamin use, the study authors remind us that there is low-level evidence, in the form of an observational study, that there may be a lower breast cancer recurrence risk among breast cancer survivors using multivitamins.
COcoa Supplement and Multivitamin Outcomes Study (COSMOS) study
A 2022 study of over 21,000 older Americans showed that a daily multivitamin and cocoa extract supplement did not lower the incidence of invasive cancer compared with a placebo. Here are the specific findings:
- No effect of multivitamin use on breast cancer incidence
- No effect of multivitamin use on colorectal cancer incidence
- A protective effect of a daily multivitamin on lung cancer incidence (a drop of over one-third; hazard ratio 0.6)
- – No effect on cardiovascular disease
- No effect on all-cause mortality
The study raised no safety concerns.
Multivitamins — My take
My views harmonize with those of the US Preventative Services Task Force and the US Institutes of Health (NIH) consensus statement: If you are healthy and have adequate dietary intake (and no risk factors for inadequate vitamin status as discussed above), there is no need for multivitamins, given insufficient evidence of their benefits (I concede that the lung cancer risk reduction needs more attention).
Still, many feel more comfortable taking a multivitamin, and the studies seem to raise no safety signals for most. While some advocate for avoiding multivitamins, multivitamins are not unreasonable for most.
Please remember that the federal government does not regulate supplements (such as vitamins, minerals, and herbs) to assure safety and effectiveness in the United States.
Fortunately, the individual components of multivitamins are safe for most adults. Vitamin E doses are typically well below levels thought to increase early mortality rates, and beta-carotene doses are lower than those linked to lung cancer. The folic acid doses are below that thought to increase cancer risk. Avoid vitamin formulations that have several times the Recommended Daily Allowance (RDA) of vitamin B12.
Also, some individuals may suffer harm from ordinary doses of vitamin A, with the vitamin associated in some observational studies with osteopenia and fractures. If you are at higher risk for osteopenia or osteoporosis, please consider avoiding supplements with vitamin A. And if you take high doses of it (say 10,000 units or more daily), you may increase the risk of harming a fetus (congenital abnormalities). The risk is nearly five times higher for those consuming 10,000 units daily compared with 5.000.
Thank you for joining me in this brief look at multivitamins and health. Do you take a multivitamin? If yes, what motivates you to do so?