by Lylah Alphonse
When it comes to vitamin D, a new report says that you need more than you used to, but less than you think you do.
"For bone health, those numbers stand up very well and will cover the vast majority of the populations," Dr. Steven Clinton of Ohio University, one of the experts involved in the Institute of Medicine study, said in a press conference today. "Because we don't have good data for vitamin D or calcium for the other outcomes, we can't draw a recommendation."
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Though they tripled their recommended intake for vitamin D—from 200 International Units (IUs) to 600 IUs for average folks—the committee discouraged people from taking more than 4,000 international units of vitamin D a day. And its recommendation for calcium intake remains much the same: 700 mg for children age 1 to 3, 1,000 mg for kids age 4 to 8, 1,300 mg for adolescents age 9 to 18, and 1,000 mg for adults over the age of 19. Breastfed infants may still need a little extra vitamin D, but the only age group at risk for a calcium deficiency is the same one that's always had problems consuming enough calcium: adolescent girls. Post-menopausal women who take calcium supplements may, in fact, be taking too much. According to another member of the panel, Dr. Glenville Jones, professor of biochemistry and medicine at Queens University in Ontario, extra doses of calcium and vitamin D may be of no help at all: "There seems to be little benefit to taking additional supplements," he explained.
Other experts, however, disagree with today's findings. In 2007, the D-Action Consortium, a group of 41 vitamin D researchers, organized by GrassrootsHealth, called for a minimal daily vitamin D intake of 2,000 IUs (10 times the recommended amount set in 1997 ) to reduce incidents of heart attack, bacterial infections like the flu, and certain types of cancer. Dr. Michael Holick, professor of medicine, physiology and biophysics at Boston University, says that recommending an increase in vitamin D intake "is a step in the right direction," but disagrees with the panel's definition of vitamin D deficiency, saying that children need 1,000 IU and adults need 2,000 to 3,000 IU daily in order to maximize bone health. And bone health, he says, is not the only benefit.
"There is a mountain of evidence linking vitamin D deficiency with many serious chronic diseases including autoimmune diseases, deadly cancers, and heart disease," he points out. "I believe that vitamin D does have important health benefits beyond bone health."
So, do we need to actively seek out more vitamin D? Yes and no. According to the Institute of Medicine study, many of our staple foods— including bread, milk, and other dairy products—are fortified with calcium and vitamin D before they even hit our tables. Also, our bodies synthesize vitamin D after exposure to sunlight. But, in order to avoid increasing skin cancer rates by advocating that people spend more time in the sun without protection, the panel based their recommendations on the assumption that people spend only the bare minimum of time out in the sun. Which means that while people are ingesting less than the minimum requirement, the level of vitamin D in their bloodstreams are just fine.
Dr. Holick, who was the first person to identify the major circulating form of vitamin D in human blood and to determine how vitamin D is synthesized in the skin, disagrees. "You cannot obtain enough vitamin D from your diet," he says. "The three-step strategy that I recommend to maintain a healthy vitamin D status is to ingest foods that naturally contain or are fortified with vitamin D along with.....read more on shine
