What's the Status of Vitamin D

By Todd Runestad December 01, 2010

The U.S. government panel in charge of setting recommended daily intake levels for vitamins today announced a large increase of vitamin D for all populations in North America.

Specifically, the Institute of Medicine (IOM) report advocated a doubling of vitamin D intake for infants (to 400 IU), a tripling of vitamin D intake for those between ages 1 and 50 (to 600 IU), a 50 percent hike in those ages 51 to 70 (to 600 IU), and a 33 percent increase for those older than 71 years old (to 800 IU).

Not that you would know it from mainstream media reports. The New York Times, for instance, had the headline: "Report Questions Need for 2 Diet Supplements."

CBS News headlined their piece, "Vitamin D Report Shocker: High Doses Unnecessary, Risky." This, despite the fact the IOM panel doubled the upper safety level, to 4,000 IU/day.

"This is hardly investigative journalism," said Robert Heaney, MD, a vitamin D researcher at Creighton University in Nebraska who was not part of the panel this time, though he was when the panel last issued recommendations, in 1997. "But the media is just parroting what the report says. The principal casualty of this is the credibility of the IOM – there were no day-to-day vitamin D scientists on the panel, and the working vitamin D community says they're off base."

The committee reviewed about 1,000 published studies, and did conclude that vitamin D along with calcium are vital for maintaining bone health. But they said the jury is out on other health effects. Access the report.

"This is likely to stir things up a bit," said Anthony Almada, president of nutrition consultancy GenR8. "The IOM did increase the vitamin D RDI by 50 percent!"

On calcium, the report said post-menopausal women should be cautious about calcium intake over concerns about kidney stones, though they advocated adolescent girls are most in need and should increase their calcium intake to 1,300 mg/day.

The other surprise in the report, beyond the down-the-rabbit-hole media coverage, is the dosage levels. Even though the IOM's recommendation tripled for most people, the research community was advocating the level be pinned at 2,000 IU/day, and the conventional wisdom said that the conservative, supplements-averse government agency would at least go to 1,000 IU/day.

"While an increase in the recommendations for vitamin D will benefit the public overall, such a conservative increase for the nutrient lags behind the mountain of research demonstrating a need for vitamin D intake at levels possibly as high as 2,000 IU/day for adults," according to Andrew Shao, Ph.D., senior vice president, scientific and regulatory affairs, for the Council for Responsible Nutrition. "The research for vitamin D has been so positive, that the medical community and consumers already have a heightened awareness of the value of this nutrient, and we’ve been anxious for the IOM to catch up."

Notably, the IOM concluded that a blood level of between 20 and 30 nanograms/millileter is adequate for bone health – and that nearly everyone is in that range.

"It's solving a problem by definition," said Heaney. "The IOM set the bar very low. The report is egregiously bad."

Vitamin D advocates say between 30ng/ml and 50ng/ml are best for optimal health.

The good news is the upper limit doubled to 4,000 IU/day. "Vitamin D is low cost and now we know it's low risk, why not take something that can benefit you with no chance of harm and at very little cost?"

The report noted that pregnant women as well as infants could benefit from more vitamin D. For pregnant women, Heaney pointed out that a recent large-scale, gold-standard double-blind, placebo controlled randomized human clinical trial showed 4,000 IU/day vitamin D raised blood levels from 30 nn/ml to 50 ng/ml and reduced by 50 percent complications of pregnancy such as low birth rates, pre-eclampsia and gestational diabetes. Another recent gold standard trial with 1,200 women showed a reduction of cancer incidence over four years of vitamin D supplementation.

"There are at least 15 to 20 recent vitamin D studies on non-skeletal systems," Heaney said. "To say the jury's out, well, the IO'’s jury is out but the evidence is there, and that's what the public needs to know."

Very few foods naturally contain vitamin D, making supplementation often necessary. Food sources with vitamin D include salmon, tuna and mackerel and fish liver oils. Most dietary sources of vitamin D come from fortified foods and beverages, most predominantly milk and cereal. Milk usually contains 100 IU/cup.

Sales of vitamin D supplements have skyrocketed over the last decade, as research and positive media headlines have driven doctor and consumer interest in the sunshine vitamin. According to Nutrition Business Journal, sales of vitamin D supplements jumped 82 percent to $430 million in 2009.

Many believe the IOM's increased vitamin D guidelines could help fuel further growth, but at least one medical professional isn't so sure.

Dennis Black, a professor of epidemiology and biostatistics at the University of California, San Francisco, told the New York Times that he believes the IOM report could actually hinder practitioner testing of vitamin D levels, and thus recommendations for vitamin D supplementation. “Everyone was hoping vitamin D would be kind of a panacea,” Black said. “I think this will have an impact on a lot of primary care providers.”

For additional government pronouncements on vitamin D, go to http://ods.od.nih.gov/factsheets/VitaminD-QuickFacts/

http://www.functionalingredientsmag.com/article/News-and-Analysis/vitamin-d-intake-levels-officially-rise.aspx