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

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.