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What Taking a Vitamin Every Day Does to Your Body

The good, the bad, and the ugly.
FACT CHECKED BY Emilia Paluszek

The vitamin and supplement market is booming—but are any of these products worth the money? "Supplements can appear on the shelf without having to prove they offer any benefits," says JoAnn E. Manson, DrPH, MD. "With limited regulation and oversight, it's also difficult to know for certain that the supplement contains the ingredients on the label and is free of contaminants." Here is what taking certain vitamins every day does to your body. Read on—and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had COVID.


Is This Multivitamin Worth It?

Smiling woman taking a pill.

Not according to researchers at Johns Hopkins, who say multivitamins not only don't prevent serious health conditions, but vitamin E and beta-carotene can actually be dangerous when taken in large doses. "Pills are not a shortcut to better health and the prevention of chronic diseases," says Larry Appel, M.D., director of the Johns Hopkins Welch Center for Prevention, Epidemiology and Clinical Research. "Other nutrition recommendations have much stronger evidence of benefits—eating a healthy diet, maintaining a healthy weight, and reducing the amount of saturated fat, trans fat, sodium and sugar you eat."


What About Vitamin D and Vitamin C For Immune Health?

young woman taking pill
Shutterstock / New Africa

While your immune system can't be "boosted," certain vitamins can help support it, providing you don't take too much. "If you are deficient in vitamin D, that does have an impact on your susceptibility to infection. So I would not mind recommending, and I do it myself taking vitamin D supplements," says Dr. Anthony Fauci, adding that Vitamin C is "a good antioxidant." "So if people want to take a gram or two at the most [of] vitamin C, that would be fine."

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Step Away From the Weight Loss Pills

Woman holding packs of pills and measuring tape in hands.

Weight loss pills are the number one supplement landing people in emergency rooms every year, being involved in over 70 percent of cases. "In recent years, many tainted weight loss products have been sold in the U.S. Hidden ingredients have included stimulants, antidepressants, diuretics, seizure medicines, and laxatives," says clinical toxicologist Rose Ann Gould Soloway, RN, BSN, MSEd, DABAT emerita. "This list includes prescription drugs, over-the-counter drugs, and drugs which are illegal to sell in the United States."

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Vitamins and a Healthy Lifestyle

older couple doing yoga in front of a laptop
Shutterstock / insta_photos

If you want to take vitamins to supplement a healthy lifestyle, great—but be under no illusion vitamins can balance out an unhealthy lifestyle lacking in regular exercise and a nutritious diet. "Supplements are never a substitute for a balanced, healthful diet," says Dr. Manson. "And they can be a distraction from healthy lifestyle practices that confer much greater benefits."

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What About Folic Acid?

folic acid

If you're a woman of reproductive age or pregnant, do not skip the folic acid! "Folic acid prevents neural tube defects in babies when women take it before and during early pregnancy," says Dr. Appel. "That's why multivitamins are recommended for young women. I don't recommend other supplements. If you follow a healthy diet, you can get all of the vitamins and minerals you need from food."

Ferozan Mast
Ferozan Mast is a science, health and wellness writer with a passion for making science and research-backed information accessible to a general audience. Read more about Ferozan