Lots of us — 86%, according to one survey — take multivitamins or supplements. And only 24% of those who take them have a documented nutritional deficiency. The rest of us, presumably, are looking for a little insurance that we’re getting the micronutrients we need.
But do these supplements make a difference? Or are we wasting our money?
In June, the US Preventive Services Task Force, an independent, volunteer expert task force, analyzed 84 studies and concluded that vitamins and supplements do little to prevent cancer or heart disease.
Manish Paranjpe, a student at Harvard Medical School in Boston, also wanted to find out about why people take supplements and the effects on health. He led a team of researchers who analyzed CDC data for 20,000 people. The study results were published in BMJ Open in November 2020, and the findings suggested that the health benefits of multivitamin and mineral supplements might be all in the minds of the people who pop them every morning.
People who take them self-report that their health is “excellent” or “very good” 30% more often than those who don’t. But the data doesn’t back up their claims. The researchers compared the people who took these supplements with those who didn’t. It turned out, there were no differences in whether they:
- Needed help with routine activities.
- Had a history of 10 chronic diseases and 19 acute conditions.
- Experienced psychological distress in the past month.
Paranjpe’s research seems to suggest that we might be better off taking other steps to improve our health. “There are more evidence-based things people can do (instead of taking multivitamins), such as eating a healthy diet or exercising,” Paranjpe said.
Studying the health benefits of supplements is tricky
It’s hard to evaluate whether multivitamin and mineral supplements make a difference, though. So many factors play into our diets that it’s hard to study the effects of individual micronutrients. It’s challenging because:
- It’s difficult to monitor what someone is eating.
- Different studies examine different products and formulations, so it’s hard to compare results.
- Manufacturers change their compositions, so it’s challenging to connect a specific nutrient to a specific health claim.
- It’s hard to study supplements for long periods to track effects.
Do you need a multivitamin?
Samantha Cassetty, a registered dietitian based in New York City and the coauthor of “Sugar Shock,” told TODAY she doesn’t recommend multivitamins for most people — she focuses more on food. “You can get most of what you need from food,” she said. “But a lot of people don’t eat that well.”
Cassetty sees the expense as the main downside of multivitamins. “If you feel the cost of a multivitamin exceeds what the value should be for you, you absolutely should not be doing that,” she said. “But if the added assurance makes you feel better, I don’t see the downside.”
Vitamin D is a nutrient Cassetty singled out as a worthwhile supplement. Most people need more vitamin D, which is involved in regulating the immune system.
Other supplements might be smart choices for certain groups of people:
- Folic acid for women who are pregnant or trying to get pregnant
- Iron for pregnant women
- Calcium for postmenopausal women
- Vitamin B12 for people over age 50
What to consider if you choose to take a multivitamin
Cassetty said some people prefer a multivitamin if they need a few different supplements, rather than taking them individually. She explained that if you want to take a multivitamin you should:
- Choose one that is as close to 100% of the recommended daily allowance (RDA) as possible. “You don’t want to see 500% of the RDA, generally speaking. You want to be in the moderate range,” she said. And below 100% is okay — you’re getting some of the nutrients you need from your food, after all.
- Take one that’s designed for your age and gender. There are products designed for women of child-bearing age, senior men and women and other subgroups.
She also pointed out that a multivitamin isn’t a replacement for a healthy diet. “If you want to take a multi for added assurance, that’s OK, but don’t take it instead of working on your eating habits,” she said. “Your primary focus should be on improving your eating habits. There is much stronger evidence for eating a plant-forward, mostly whole foods diet than there is for multivitamins.”