Multivitamins—benefits and risks

Created date

June 27th, 2019

Dr. Narrett leads the medical team at all Erickson Living communities. A graduate of Harvard Medical School, he has been providing care for seniors for over three decades.

Vitamins are essential to our good health, and they cannot be manufactured by our bodies. They must be ingested in the food we eat or taken in a dietary supplement. This has led to the explosive growth of the vitamin industry, with vitamin intake becoming commonplace among seniors. More than half of adults 60 years of age and up take at least one vitamin pill a day. The most common supplement taken by a full one-third of this age group is a multivitamin/mineral combination. 

But do multivitamins improve your health above and beyond eating a well-balanced and nutritious diet? 

This is a remarkably difficult question to answer, but after a comprehensive review of the subject, the U.S. Preventive Services Task Force concluded in 2014 that there is not enough evidence that multivitamins and various supplements prevent cancer or cardiovascular disease, or that benefits outweigh potential harms. On the other hand, there are now many studies that show eating a diet high in antioxidant-rich fruits and vegetables reduces risk for these conditions. This suggests that rather than taking a pill, eating a balanced diet high in nutrients is the most healthful approach. This certainly makes sense, given that humans have been obtaining nutrients from food since time immemorial, and multivitamin pills are new to us all. 

It is also important to realize that foods have many more components than multivitamins that may make the difference in achieving good health. Just recently, Harvard researchers found that cruciferous vegetables like broccoli, kale, and Brussels sprouts contain indole-3-carbinol, a substance that may play an important role in the body’s natural ability to suppress tumor growth. This food-based discovery may add another opportunity for medicine to further cancer treatment.

B12 and vitamin D

While multivitamins may not be better than a well-balanced diet, certain vitamins may be of real value, especially if your diet is limited. For instance, vegans should consider vitamin B12 supplements, as their diet may be lacking in this essential nutrient. Vitamin D also comes to mind. A significant number of seniors have low vitamin D levels because the average dietary intake of this vitamin typically falls short of recommended amounts. 

While vitamins and dietary supplements may add value, they can also come with risk. We typically assume they are safe because they don’t require a prescription, but they can cause significant harm. In 2011, a University of Illinois study found that greater than 15% of seniors took potentially fatal combinations of prescription drugs, over-the-counter medications, and dietary supplements. Unlike medicines, these supplements are not subject to rigorous research and review by the Food and Drug Administration. We often do not know the full extent of how supplements and vitamin combinations affect health; even the amount of active ingredient can vary from product to product and be negligible in one bottle and dangerously high in another. 

For all of these reasons, please discuss any and all vitamin and dietary supplements along with your prescriptions with your doctor. Vitamin supplements require a careful discussion as they represent both real opportunity and risk. 

While some supplemental vitamins may provide benefits, a healthful balanced diet is the very best place to start toward achieving good nutrition.

In good health,

Dr. Narrett