Benefits of Multivitamins May Be Linked to Placebo Effect, Study Finds

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Key Takeaways

  • A study on 21,000 people found multivitamin users are more likely to say they have excellent health, but show no differences in clinically measurable health outcomes than people who don’t take vitamins.
  • More research is needed to determine if the self-reported benefits of vitamins are the result of the placebo effect, as well as whether supplements can make a long-term impact on health. 
  • Health experts encourage people to talk to their doctors before taking any vitamin or supplement.

For many of us, the daily ritual of taking a multivitamin is one easy step we take toward better health. We get peace of mind knowing that our bodies are getting what they need, regardless of whether we have time to prepare healthy meals. 

But are multivitamins actually making us healthier?

The benefits of multivitamins may, in fact, be all in our head, according to a new study. Published in the journal BMJ Open, the report looked at health data on more than 21,000 people. The researchers found that there were no clinically measurable health differences in people who took multivitamins, even though they tended to report better overall health than participants who didn’t take the dietary supplements.

Despite the findings, doctors are mixed on whether people should continue taking multivitamins. Here’s what you need to know about the latest study on vitamins.

Study Finds Vitamins Might Not Improve Health

To learn more about the impact of multivitamins on health, a team of 18 researchers looked at data on 21,603 adults from the 2012 National Health Interview Survey. It asked participants a variety of questions about their health, including whether they had certain chronic conditions, as well as whether they had taken multivitamins over the last 12 months.

The researchers split the group into 4,933 people who had taken multivitamins, and 16,670 who didn’t use the supplements. The data showed no differences in clinically measurable health outcomes, such as a history of 10 chronic diseases, the presence of certain health conditions, the need for assistance with daily activities, or the severity of psychological distress, between the two groups.

John Prucha, MD

There’s a pretty big body of research that shows that multivitamins, by and large, aren’t helpful for the general population as far as affecting incidents of disease or mortality outcomes.

— John Prucha, MD

“As the article mentioned, there’s a pretty big body of research that shows that multivitamins, by and large, aren’t helpful for the general population as far as affecting incidents of disease or mortality outcomes,” says John Prucha, MD, a board-certified family medicine provider with UCHealth Primary Care-Quincy in Aurora, Colorado. 

Despite the lack of measurable health differences, the two groups differed in one key area: how well they perceived their own health. Those who took multivitamins were 30% more likely to report having “excellent or good overall health” than the rest of the participants.

More research is needed to determine why multivitamins make people feel better about their overall health, but the study authors say that it might be the result of a placebo effect—in other words, participants’ belief that vitamins would help their health led to improvements in self-perceived outcomes.

The researchers also said that it’s possible that people who already have positive views about their health are more likely to take multivitamins.

Limitations of Multivitamin Study

Key limitations of this study make its findings more suited to generating future hypotheses and research, rather than hard conclusions about multivitamins, says Scott Kaiser, MD, a board-certified family physician and director of geriatric cognitive health for the Pacific Neuroscience Institute at Providence Saint John’s Health Center in Santa Monica, California.

He says that grouping together all participants who took a multivitamin in the last 12 months—whether they took one tablet in that time period, diligently took a multivitamin every day, or even took excessive amounts of vitamins and supplements—makes it difficult to determine whether multivitamins made a difference in their health.

What’s more, the research doesn’t account for potential long-term effects of multivitamins on health.

“You’re just looking at a snapshot of health in time, so it’s difficult to tell,” explains Dr. Kaiser.

Limitations aside, the study does cast a harsh spotlight on the growing market for vitamins and supplements, estimated to reach $230.73 billion by 2027, and the lack of conclusive evidence that these products are doing anything for our health. 

“I joke that all multivitamins do is make expensive pee, since your body basically filters everything out,” says Dr. Prucha.

Should You Take Multivitamins?

The verdict’s still out when it comes to whether everyone should take a multivitamin or not. In general, there should be a more individualized approach to vitamin and supplement use in order to help people achieve specific health goals, such as better cognition or disease prevention, rather than the one-size-fits-all approach of a multivitamin, says Dr. Kaiser.

Scott Kaiser, MD

It’s very hard to make general recommendations when people ask what vitamins or minerals they should take. It depends on any individual’s situation.

— Scott Kaiser, MD

“It’s very hard to make general recommendations when people ask what vitamins or minerals they should take. It depends on any individual's situation,” he adds.

Some people may also need to take specific vitamins if they have certain medical conditions or nutritional deficiencies.

Doctors may recommend that a vegan take vitamin B12, since that vitamin isn’t found in most plant-based foods. Likewise, physicians may encourage patients with osteoporosis to supplement with calcium to help with bone health. These recommendations are made on a case-by-case basis between doctors and their patients, though, and they don’t necessarily apply to everyone.

Remember, there’s no shortcut to great health. Health experts say that you may be better off following evidence-backed recommendations, such as eating a nutrient-dense diet, getting sunshine, and exercising regularly, than shelling out for vitamins and supplements. 

“You can spend a fortune on supplements that offer no real clinical benefits,” says Dr. Prucha. “I tell people they should reconsider because their money may be better spent on a gym membership or doubling down on fresh veggies.” 

What This Means for You

If you take multivitamins, there’s a chance that you’re spending money on products that aren’t doing your health much measurable good. Don’t ditch your vitamins just yet, though. Multivitamins can help people feel better about their overall health, which may have value. More research is needed to determine exactly how dietary supplements impact our health over the long-term. 

It’s always a smart idea to talk to your doctor before adding any vitamin or supplement to your health regimen. You can work together with your physician to determine exactly which vitamins (if any) make sense for you and track whether they’re helping you achieve your health goals. 

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  1. Paranjpe MD, Chin AC, Paranjpe I, et al. Self-reported health without clinically measurable benefits among adult users of multivitamin and multimineral supplements: a cross-sectional studyBMJ Open. 2020;10(11):e039119. doi:10.1136/bmjopen-2020-039119

  2. Dietary supplements market worth $230.7 billion by 2027. Grand View Research. Published Feb. 2020.

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