The Truth About Vitamin D: How Much Vitamin D Do You Need?

WebMD feature series on vitamin D.

From the WebMD Archives

How much vitamin D do I need?

In November 2010, the Institute of Medicine's expert committee set a new "dietary reference intake" for vitamin D.

Assuming that a person gets virtually no vitamin D from sunshine -- and that this person gets adequate amounts of calcium -- the IOM committee recommends getting the following amounts of vitamin D from diet or supplements (Note that the IOM's upper limit is not a recommended intake, but what the IOM considers the highest safe level):

  • Infants age 0 to 6 months: adequate intake, 400 IU/day; maximum safe upper level of intake, 1,000 IU/day
  • Infants age 6 to 12 months: adequate intake, 400 IU/day; maximum safe upper level of intake, 1,500 IU/day
  • Age 1-3 years: adequate intake, 600 IU/day; maximum safe upper level of intake, 2,500 IU/day
  • Age 4-8 years: adequate intake, 600 IU/day; maximum safe upper level of intake, 3,000 IU/day
  • Age 9-70: adequate intake, 600 IU/day; maximum safe upper level of intake, 4,000 IU/day
  • Age 71+ years: adequate intake, 800 IU/day; maximum safe upper level of intake, 4,000 IU/day

That's not enough, says Boston University vitamin D expert Michael Holick, MD, PhD, professor of medicine, physiology, and biophysics, Boston University Medical Center. Holick recommends a dose of 1,000 IU a day of vitamin D for both infants and adults -- unless they're getting plenty of safe sun exposure.

In 2008, the American Academy of Pediatrics recommended that breastfed infants receive 400 IU of vitamin D every day until they are weaned. This doubled the AAP's previous recommendation.

The AAP also recommends 400 IU/day of vitamin D for children and teens who drink less than a quart of vitamin D-fortified milk per day.

The Vitamin D Council recommends that healthy adults take 2,000 IU of vitamin D daily -- more if they get little or no sun exposure.

There's evidence that people with a lot of body fat need more vitamin D than lean people.

But it's clear that the IOM's conservative recommendations will stir debate in the scientific and medical communities. Here's a rule of thumb: If you're considering taking more vitamin D than the IOM committee recommends, first check with your doctor or pediatrician.

Next: Can I get too much vitamin D?

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WebMD Feature Reviewed by Brunilda Nazario, MD on December 17, 2009

Sources

SOURCES:

Ross, A.C. Institute of Medicine, "Dietary Reference Intakes for Calcium and Vitamin D," Nov. 30, 2010.

Cannell, J.J. and Hollis, B.W. Alternative Medicine Review, March 2008; vol 13: pp 6-20.

Holick, M.F. Journal of Clinical Endocrinology and Metabolism, March 2008; vol 93: pp 677-681.

Autier, P. and Gandini, S. Archives of Internal Medicine, Sept. 10, 2007; vol 167: pp 1730-1737.

Holick, M.F. and Chen, T.C. American Journal of Clinical Nutrition, 2008; vol 87: pp 1080S-1086S.

Bordelon, P. American Family Physician, Oct. 15, 2009; vol 80: pp 841-846.

Rovner, A.J. and O'Brien, K.O. Archives of Pediatric and Adolescent Medicine, June 2008; vol 162: pp 513-519.

Pepper, K.J. Endocrinology Practice, 2009; vol 15: pp 95-103.

WebMD Health News: " Vitamin D Deficiency Worsens Breast Cancer?"

WebMD Feature: " Are You Getting Enough Vitamin D?"

WebMD Health News: " Vitamin D Deficiency May Hurt Heart."

WebMD Health News: " Calcium/Vitamin D Slows Weight Gain."

WebMD Health News: " Vitamin D Fights Colon Cancer."

WebMD Health News: " Vitamin D Compounds May Fight Prostate Cancer."

National Institutes of Health Office of Dietary Supplements, Dietary Supplement Fact Sheet: Vitamin D, updated Nov. 13, 2009.

The Vitamin D Council web site.

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