Do Multivitamins Work? Who Should and Shouldn’t Take Them

Experts are at odds over the effectiveness of multivitamins
Person looking at a vitamin container.

More than half of Americans take multivitamins. But can a daily pill really make up for a poor diet?

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Anyone who is malnourished or has a nutritional deficiency should talk to their doctor about taking a multivitamin, says internist Raul Seballos, MD. This can include those who are on a low-calorie diet or avoid certain foods like vegetarians and vegans. Those who have impaired absorption due to conditions like Crohn’s disease, ulcerative colitis, celiac disease or a history of gastric bypass surgery should also speak to their doctor.

But for everyone else, it’s important to ask yourself a few questions.

“Ask yourself, ‘Am I doing everything possible to optimize my overall health before taking a multivitamin and/or supplement?’” says Dr. Seballos. “Smart lifestyle choices are your best guarantee of future health.”

Registered dietitian Anna Taylor, RD, agrees.

“So many of my patients tell me they know their diet is not great but that I shouldn’t worry because at least they take a multivitamin,” says Taylor. “But multivitamins aren’t a surefire way to get what you need.”

Here’s what you need to know about multivitamins.

What are multivitamins?

A multivitamin supplement contains a combination of different vitamins and minerals. You can take a multivitamin as a capsule, tablet, gummy, powder or liquid.

There are many types of multivitamins available online and at stores. But not all multivitamins are created equally. As there isn’t a standard list of ingredients that each company must follow or include, you may notice differences in which vitamins are included and how much of each.

So, how do you know which multivitamin is right for you?

First, it’s best to talk to a doctor if you want to take a multivitamin. Not only can they help determine if you should take one, but they can also help figure out which one might be best for you.

And make sure you do your homework and read labels. Some multivitamins are designed for a specific age or sex, while others may be formulated for those who are pregnant or nursing.

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And if you do choose to take a multivitamin, those nutrients are best absorbed and tolerated if you take them with food. Depending on your health status, check which ingredients to limit or include in a multivitamin.

A multivitamin generally includes:

  • Calcium.
  • Folate.
  • Iron.
  • Magnesium.
  • Vitamin B-12.
  • Vitamin D.
  • Zinc.

Do multivitamins help your overall health?

Experts are at odds over the effectiveness of multivitamins. While some think they supply missing nutrients, others say they’re nothing more than an expensive crutch.

What does the research say?

The U.S. Preventive Services Task Force concludes that there’s insufficient evidence to support any benefit from vitamin and mineral supplements for the prevention of cancer or cardiovascular disease.

For men and people assigned male at birth (AMAB), multivitamins won’t prevent common cancers. Taking a multivitamin also won’t lower your risks for the most common male cancers like prostate, colon and lung cancer. And taking a multivitamin won’t lower your risk of dying from cancer.

For men and people AMAB ages 65 years or older, multivitamins don’t provide cognitive benefits either. In one study, nearly 6,000 male physicians over 65 years were evaluated for cognitive function. Memory loss and cognitive performance were similar in men who took a multivitamin and those who didn’t.

For women and people assigned female at birth (AFAB), multivitamins won’t help you live longer. A study found that those who took multivitamins actually had a higher risk of early death.

Overall, it’s key to remember that taking a multivitamin won’t replace healthy habits.

“Taking a multivitamin is no substitute for healthy lifestyle choices like exercising and eating a balanced diet,” says Dr. Seballos.

Multivitamin risks

Multivitamins are generally safe for most people. But there are some risks for certain individuals.

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One study found that calcium supplements can increase the risk of a heart attack. Many doctors recommend that people with a high risk of heart disease get their calcium through diet rather than supplements.

Another study found that certain dietary supplements, including multivitamins, folic acid, iron and copper, appeared to be associated with an increased risk of death in older women.

If you’re a smoker or a former smoker, you should avoid a multivitamin with a large amount of beta-carotene and vitamin A, as those ingredients may increase the risk of lung cancer.

You also want to watch the amount of vitamin A if you’re pregnant, as it can lead to an increased risk of birth defects.

While multivitamins don’t typically interact with medication, if you take any medication that reduces blood clotting, you should talk to your doctor before starting a multivitamin that has vitamin K. Vitamin K can lower the drug’s effectiveness.

But not all vitamins come with health risks — especially if you use them after consulting a doctor first. Some essential vitamins and nutrients are best absorbed in pill form.

These include:

  • Folic acid. For women who are pregnant and of childbearing years, this synthetic version of folate, which helps prevent birth defects, is best absorbed in a supplement.
  • Vitamin D. Taylor says that vitamin D may be most beneficial in pill form because it contains the type of vitamin D that we absorb best — the kind we get through the sun, not food.

When to talk to your doctor

When it comes to the essential nutrients our bodies need to thrive, it’s hard to beat what nature provides.

Dr. Seballos stresses the importance of telling your doctor about all the vitamins and supplements you take.

“It’s important to tell your doctor what you are taking to avoid any potential drug interactions with your prescribed medications,” he adds. “Additionally, exercise, a well-balanced diet, a good night’s sleep and work-life balance trump any vitamins you can take to optimize your personal health.”

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