It's estimated that over 40 million Americans take a daily multivitamin. And many also take other vitamins and mineral supplements in addition to a multivitamin. While everyone worries about not getting enough vitamins, is it possible to get too much?

It dependsIt depends

Vitamins are either water-soluble or fat-soluble. Water-soluble vitamins are vitamins that are dissolved in water and easily absorbed into tissue. Because water-soluble vitamins are not stored in the body, they need to be regularly replenished through diet. Any excess water-soluble vitamins are quickly excreted through urine. Therefore, it's rare to overdose on water-soluble vitamins. Common water-soluble vitamins include:

  • Vitamin B1
  • Vitamin B2
  • Vitamin B3
  • Vitamin B6
  • Folate
  • Vitamin B12
  • Biotin
  • Pantothenic acid
  • Vitamin C

Fat-soluble vitamins, on the other hand, are dissolved in fats and are distributed through the bloodstream. Excess amounts of fat-soluble vitamins are stored in the liver and fatty tissues for future use. This means that you can overdose on fat-soluble vitamins. Common fat-soluble vitamins are:

  • Vitamin A
  • Vitamin D
  • Vitamin E
  • Vitamin K

Know your limitsKnow your limits

The Food and Nutrition Board of the Health and Medicine Division of the National Academies of Science, Engineering, and Medicine have established Tolerable Upper Intake Levels (UL) for all vitamins and minerals. The ULs for fat-soluble vitamins are:

  • 3,000 mcg for vitamin A
  • 4,000 IU for vitamin D
  • 1,000 mg for vitamin E

ULs haven't been set for vitamin K.

Some water-soluble vitamins also have ULs:

  • 2,000 mg for vitamin C
  • 35 mg for niacin
  • 100 mg for vitamin B6
  • 1,000 mcg for folic acid
  • 3,500 mg for choline

Play it safePlay it safe

Remember that there's no real advantage to taking more than the recommended amounts of vitamins. You should also consult with your doctor before taking a vitamin or dietary supplement in case of interactions. If you do decide to take vitamins, make sure to follow the label directions.

Vitamins are not a substitute for an unhealthy diet, so you should continue to focus on eating healthy foods, such as fruits, vegetables, lean proteins, and whole grains.

References
  1. "Can You Really Overdose on Vitamins?," VeryWellFit, November 11, 2018.
  2. "Fat-Soluble vs Water-Soluble Vitamins," VeryWell, October 15, 2018.
  3. "Getting too Much of Vitamins and Minerals," WebMD, n.d.

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