Do multivitamins really work?

People choose to take multivitamins for a variety of reasons, including helping the body avoid nutritional deficiencies, support certain health outcomes, or increase energy levels. But multivitamins are supplements, and with any supplement or new drug you take, it’s important to ask questions about how it will actually benefit you. As a dietitian, when people ask me “do multivitamins work?”, my boring answer is “it depends.”

Multivitamins are supplements that contain many different vitamins and minerals, often along with other ingredients. They are available in many forms, such as tablets, capsules, chewing gum, powders, and liquids, and about one-third of all adults in the United States take one.

But whether you (or your family) should take a multivitamin depends on a number of factors, from diet to medical history. Up front, answers to all your questions about multivitamins, including whether multivitamins work and whether or not you should be taking them.

Do multivitamins work?

For some people, yes, multivitamins work.

What you eat and drink supplies your body with the nutrients necessary to allow the body to function properly. In a perfect world, most people would eat enough nutrient-dense foods like produce, beans, nuts, and legumes to provide the body with all the nutrients it needs in adequate amounts. Unfortunately, however, most Americans fall short when it comes to getting the food balance right. For example, the CDC suggests that only 10% of American adults eat the recommended servings of fruits and vegetables each day.

And that’s where multivitamins come into play. A multivitamin is a supplement that contains many vitamins. “They’re great because you can get a variety of essential nutrients in one vitamin instead of taking the nutrients individually,” Melissa Mitri, MS, RD, registered dietitian and nutrition writer, told POPSUGAR. Some multivitamins, many also contain minerals, herbs, or other supplements.

Taking a multivitamin can provide the body with nutrients it may not be getting through your diet, especially if you don’t eat enough of certain food groups (or eliminate certain foods altogether). In theory, taking a multivitamin will ensure that your body gets enough of these micronutrients, even if your diet is deficient. But every body is different and what works for one person may not work for you.

What happens to your body when you start taking multivitamins?

Intuitively, it makes sense to believe that taking a multivitamin is a simple step to make sure you don’t have nutritional gaps. But when you look closely at the medical literature, the arguments about whether everyone would benefit from one are mixed.

The latest data published in Alzheimer’s disease and dementia showed that older adults who took a daily Centrum Silver multivitamin supplement improved cognition and memory. And other data show that there may be benefits to eye health when certain multivitamins are taken. Especially for pregnant women, a prenatal vitamin containing certain minerals can significantly reduce a wide range of pregnancy complications (such as anemia and gestational diabetes).

“Scientifically supported benefits of taking multivitamins include improved immune function, improved mental health and better energy levels,” Mitri shared. She also added that “specific populations may benefit more from multivitamins, including vegetarians and vegans, who lack critical nutrients in their diets.”

Side effects of multivitamins

Taking multivitamins does not come without risks and may not be for everyone.

According to the analysis in the magazine Annals of Internal Medicine, after analyzing research involving 450,000 people, researchers found that multivitamins did not reduce the risk of heart disease or cancer. And for certain populations, taking certain nutritional supplements can be risky. For example, taking supplements containing beta-carotene is associated with an increased risk of lung cancer in those with a history of cigarette smoking.

Mitri explained that taking a multivitamin every day can also cause some digestive problems, “especially if it contains above 100% of your Recommended Daily Allowance (RDA) of certain nutrients like iron, zinc, or vitamin C.” Exceeding the RDA can also negatively affect certain aspects of your health, such as taking megadoses of vitamin D can be linked to the development of kidney stones.

Should You Take Multivitamins?

Whether you should take a multivitamin depends on many factors, including your medical history and your diet. While it’s true that some people may benefit from taking a multivitamin, that doesn’t mean it will help all people. Ultimately, the decision to take a multivitamin should involve weighing your specific risks and benefits with your healthcare provider and deciding what is best for you.