Advertisement

Can high doses of vitamin supplements be dangerous?

Dariush Mozaffarian, MD
Internal Medicine
Certainly, getting too little of essential micronutrients can be harmful to your health, especially over the long haul. But getting too much can have equally worrisome effects, many of which show up more swiftly. Most troublesome are excesses of fat-soluble vitamins (vitamins A, E, and K), which the body may easily stockpile to the point of reaching toxic doses.  High doses of supplements -- usually from taking individual vitamin and mineral supplements in addition to a powerful multivitamin -- are often at fault.

It's much harder to get dangerous amounts of micronutrients from food, partly because of the body's natural checks and balances. When iron stores are full, for example, your body normally absorbs less iron from food unless a genetic disorder or other problem interferes. Your body also slows the conversion of beta carotene to vitamin A when it already has enough vitamin A from supplements or food sources. But it is still possible to overdo it.

Continue Learning about Vitamins

The Best Place to Store Vitamins
The Best Place to Store Vitamins
Keeping your vitamins fresh and potent longer means thinking like a real estate agent: location, location, location. And the worst location? Your bat...
Read More
Should I take vitamins with an expired date?
Univ. of Nev. School of Medicine, Family MedicineUniv. of Nev. School of Medicine, Family Medicine
The FDA does not require that expiration dates be printed on vitamin bottles. However, even vita...
More Answers
7 Supplements You Probably Don’t Need
7 Supplements You Probably Don’t Need7 Supplements You Probably Don’t Need7 Supplements You Probably Don’t Need7 Supplements You Probably Don’t Need
Hit the kitchen before you head to the pharmacy—you can get nearly all your essential vitamins and minerals from food. Nearly 68 percent of Americans ...
Start Slideshow
Can You Take Too Much of a Vitamin or Mineral?
Can You Take Too Much of a Vitamin or Mineral?

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.