On November 30, 2010 The Institute of Medicine (IOM) published a report on vitamin D which generated significant media coverage as well as controversies regarding how to interpret the IOM findings and recommendations (see Huffington Post and Wall Street Journal).

The SIO asked the experts, Drs. Crew , Plotnikoff and Holick who discussed this topic in the vitamin D session of the SIO 2010 annual conference to share their thoughts on this IOM report.

Dr. Kathy Crew, Columbia University:

I read the IOM report and I do believe they took a conservative approach in terms of making broad recommendations on vitamin D for the general public. In spite of the extensive published research on vitamin D, this highlights the fact that much is still unknown about the potential role of supplementation for preventing a number of chronic diseases and the need for more randomized controlled trials.

I thought it was interesting that although the IOM report focused on the potential dangers of high-dose vitamin D, they still raised the RDA from 400 to 600IU daily and the upper safety limit was doubled from 2000IU to 4000IU daily. This is still progress in terms of being able to raise people's serum 25(OH)D to sufficient levels.

Dr. Gregory A. Plotnikoff, Abbott Northwestern Hospital:

The IOM’s report released last week concluded that there is a strong body of evidence that substantiates the importance of vitamin D and calcium in promoting bone growth and maintenance of bone strength. In response, the IOM tripled their vitamin D recommendations for people aged 50 or less to 600 IUs per day.

However, the IOM report made several mistakes.

First, their definition of deficiency, less than 20 ng/ml, is quite out of line with biomarker status for vitamin D function. For example, increasing vitamin D status from 20 ng/ml to 30 ng/ml increases calcium absorption by 65%. PTH is minimized at levels greater than 40 ng/ml. Raising 25(OH) D levels from 10 to 30 ng/ml improves insulin sensitivity by 60%.

Second, they did not emphasize enough that their recommendations are only for bone health. They did not emphasize enough that their recommendations are for the general, healthy population who are not being tested for deficiency and working with an informed health professional.

Third, they stated that most Americans, with few exceptions, are vitamin D replete. This contradicts CDC NHANES data published in 2008. Additionally, they provided no evidence to support their assertion that 600 IUs a day will replenish deficiencies. Minnesota data demonstrates that those who are deficient will remain deficient on this dosing.

Fourth, the IOM focused on dosing rather than achievement of serum levels. Thus, they were aiming for a “one size fits all” recommendation rather than acknowledge the differences between black and white, young and old, thin and big, Tampa, Florida and Anchorage, Alaska. This makes no scientific sense.

Fifth, the IOM stated that there is not enough evidence for dosing requirements to influence any outcomes for other health concerns. The IOM missed the much more important question of what serum level we need to achieve to minimize risk of health concerns.

From our study of 10,700 Allina health care employees, we found that over 60% did not meet the minimal level of 30 ng/ml and 6% were profoundly deficient (<10 ng/ml). This was despite most people being on a multivitamin with 400 IUs of vitamin D per day.

From this, we can state that most Minnesotans do need supplementation. And, from clinical experience, we can say with great certainty that normalizing levels often result quickly in significant health quality of life improvements that can include pain reduction, increased strength and a greater sense of vitality.

I agree with one of the IOM reviewers, the highly respected endocrinologist Robert Heaney, MD, who stated publicly, "I don’t think this does anything to create confidence in IOM recommendations. We were concerned that our review might be interpreted as approval," he said. "I certainly do not approve of this report."

Dr. Michael Holick, Boston University:

I was pleased to see that the IOM recognized that the present recommendations are woefully inadequate and that they have now recommended a substantial 200% increase in the vitamin D intake for children and adults. The issue is whether the increase is enough to satisfy the body’s requirement for vitamin D not only for bone health but for other health benefits that have been well documented over the past decade.

Based on the literature regarding blood levels of 25-hydroxyvitamin D as they relate to PTH levels there is no question that the PTH levels do not plateau and reach baseline until the 25-hydroxyvitamin D level is at least 25 ng/ml and most studies suggest that in most adults this occurs above 30 ng/ml. The literature demonstrates that for every 100 IU of vitamin D ingested the blood level of 25-hydroxyvitamin D increases by ~1 ng/ml . Thus for children and adults to obtain a blood level above 30 ng/ml requires that they take at least 1000 IU and 2000 IU respectively of vitamin D daily. There is no downside to increasing vitamin D intake.

The committee now recognizes that vitamin D is not as toxic as once thought and have at least raised the upper limit to 4000 IU. The committee report does not provide guidance for what the upper-level of 25-hydroxyvitamin D can reach before there is concern about toxicity. Most of the reference laboratories and from my own experience a blood level of 25-hydroxyvitamin D can easily reach 100 ng/ml without being concerned about toxicity. To obtain a blood level of 25-hydroxyvitamin D to 100 ng/ml an adult would need to ingest between 6000-10,000 IU of vitamin D a day for at least two months. A study conducted in healthy adults who ingested10,000 IU of vitamin D a day for five months demonstrated no toxicity. Therefore although the committee's recommendation for the upper limit of 4000 IU is a significant improvement from the past recommendation it is still much lower than what has been observed by most of the published literature.

Putting this into perspective for the past decade the IOM has recommended that all children and adults only needed 200 IU of vitamin D a day to satisfy their vitamin D requirement for bone health. However now they recommend three times this amount and therefore one has to wonder what the consequences were for children and adults who only ingested the recommended 200 IU of vitamin D a day on their bone health for the past decade? As new studies are published it is likely that there will be new revelations based on randomized controlled trials demonstrating other healthful benefits of vitamin D when given in much higher doses than that recommended by the IOM. The recent observation that schoolchildren who received 1200 IU of vitamin D a day in a randomized placebo controlled trial from December through March reduced their risk of developing an influenza A infection by almost 50% is just one example for why children and adults should increase their vitamin D intake to at least 2 to 3 times what is recommended by the IOM.