For most people, a multivitamin is probably not necessary to improve health.
TL/DR: If you eat a varied diet that contains many fruits and vegetables, you probably do not need to supplement with a multivitamin. There is no evidence that vitamins reduce the development of chronic illnesses such as heart disease or significantly reduce risk of death from cancer. People with certain health conditions like pregnancy or prior weight loss surgery might need to supplement. Some vitamins can cause serious harm if taken in too high amounts, so avoid multiple supplements with overlapping ingredients.
Vitamins are tiny compounds that are a necessary part of our diet because they cannot be made by our bodies (some exceptions include vitamin D3, which our skin makes when exposed to sunlight!). Vitamins are found all around us in every food we eat – fruits, veggies, beans and nuts provide an array of nutrients as do animal sourced foods like milk, eggs and meat. Processed foods also claim to contain vitamins aimed at making us healthier- just peek at the back of your cereal box!
Up to a third of adults in the U.S. also routinely grab a multivitamin, which combines vitamins A, B2, B6, B12, C, D, E and other minerals to make a convenient shortcut to good health. But what does the data say about our overall health and the use of multivitamins?
The effect of vitamin supplementation is a difficult thing to study, although scientists have certainly tried. One big problem is that not all supplements are created equally, and the FDA doesn’t test and regulate their ingredients the way they do with medications. Also, there is a lack of consensus about how much of each vitamin we actually need everyday as well as difficulties with measuring exactly how much is in our bodies.
However, some evidence is available – so far studies do NOT show that multivitamins improve health for people who eat a well-balanced diet. The US Preventive Services Task Force (USPSTF) performed a large review of 84 individual trials that showed multivitamin use provided no significant reduction in development of cardiovascular disease or reduced rate of death overall. There was a small benefit found for multivitamin use with reduction in cancer, but there was no significant reduction in death from cancer overall despite this.
Many people still choose a daily multivitamin despite lack of clear benefit for our health, but we can have too much of a good thing. Some vitamins can CAUSE harm if you take too much of them. Fat-soluble vitamins including D, A, E and K accumulate in our bodies and when taken in high enough amounts can cause life threatening problems like liver failure. Of course, the amounts found in multivitamins are well below this dangerous level, but there is potential for harm when multiple supplements are used together. Another downside is that vitamins cost a lot – Americans spend tens of billions of dollars annually on supplements despite lack of clear evidence that they make us healthier.
There are some specific health conditions and behaviors that might make supplementing with a multivitamin a good idea, such as:
-Before and during pregnancy
-Eating a diet poor in nutrients, or limited access to fruit and vegetable options
-A history of weight loss surgery that can alter how you absorb vitamins from food
-Chronic heavy alcohol use
If you aren’t sure whether your diet has gaps that should be filled by a multivitamin or specific supplement, consult with your healthcare provider. Another good resource is to consult with a Registered Dietician, or R.D. – a member of the healthcare team with expertise in nutrition counseling.
Stay safe, eat well!
Love,
Those Nerdy Girls
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Links:
USPSTF: Vitamin and Mineral Supplements for Primary Prevention
Multivitamins in the Prevention of Cancer and Cardiovascular Disease
USPSTF Guideline on Multivitamin Supplementation for Preventive Medicine
