A n expert committee of the Institute of Medicine (IOM), which sets recommended daily levels for nu- trients, says children and adults under age 71 need 600 IU of vitamin D daily, while older adults need 800 IU. Thats an increase from levels set in 1997, which ranged from 200-600 IU daily, and from the 400 IU used in nutrition labels on food.But its not as high as some vitamin- D enthusiasts hoped for, and the IOM report downplayed claims for benefts of the sunshine vitamin against heart disease, cancer and other illnesses. It stated, The evidence does not sup- port a basis for a causal relationship between vitamin D and many of the numerous health outcomes purported to be affected by vitamin D intake.So the expert panel based its up- dated recommendations solely on bone- health needs. Even there, however, the IOM departed from what other expert groups have concluded based on the same evidence from randomized clini- cal trials-particularly regarding those at high risk for vitamin D defciency.The 800 IU intake for older adults is not all that different from recommen- dations by other groups of 800-1,000 IU, explains Bess Dawson-Hughes, MD, director of Tufts HNRCA Bone Metabolism Laboratory. Whats different is that the IOM sees that as enough to cover everyone.When the IOM sets Dietary Refer- ence Intakes (DRIs), those recommen- dations are for healthy people. But Dr. Dawson-Hughes notes that other experts believe the 600-800 IU levels are not suffcient for people at high risk for vitamin D defciency, including:
- Those with little effective sun ex- posure, which the body uses to produce its own vitamin D, such as those with very dark skin, elderly in institutions, people who cover up or use sunscreen when outdoors, and winter residents of northern latitudes.
- Osteoporosis patients.
- Those with gastrointestinal dis- orders that affect vitamin D absorption.
- Patients on medication that causes vitamin D to break down more rapidly.
- People with a lot of body fat.
A lot of people in the general pub- lic are at increased risk, Dr. Dawson- Hughes points out. If youre among them, she advises getting a blood test for vitamin D defciency, then being re-tested after three months to make sure your intake has been corrected. (No expert organization recommends across-the-board testing of average- and low-risk individuals, she adds. Its unnecessary and adds to medical costs.)T he IOM panel also concluded, contrary to some re- ports, that most Americans do get enough vitamin D. But Dr. Dawson-Hughes says thats a question of defn- ing enough: While research at Tufts and other laborato- ries suggests 30 nanograms/milliliter (ng/mL) of vitamin D is the optimum blood level for bone health, the IOM used 20 ng/mLIf you dont get much sun exposure, Dr. Dawson-Hughes says, the higher 30 ng/mL level is diffcult to achieve from diet alone. So if you decide to take vitamin D supplements despite the IOM report, as a little insurance, most experts wont argue. Everyone agrees that there is no evidence of danger from vitamin D intake up to 4,000 IU, Dr. Dawson- Hughes says. You wont be hurting yourself.Besides, theres no reason to think the optimal level for other vitamin D benefts-if subsequent randomized clinical trials prove they exist-would necessarily be the same as for your bones.We need a lot more information about other vitamin D benefts, Dr. Dawson-Hughes says. The IOM could not have used any other standard of evidence at this juncture.The panel also tweaked IOM recommendations for calci- um intake, dropping the daily target for men ages 51-70 from 1,200 milligrams to 1,000. The updated calcium recommen- dations now call for 1,000 milligrams daily for adults ages 19-50 and men up until age 71, 1,200 mg daily for women beginning at age 51 and men age 71 and older. Dietary Reference Intakes for Calcium and Vitamin D, <www.iom. edu/Reports/2010/Dietary-Reference-Intakes-for-Calcium-and-Vitamin-D.aspx>