Vitamin D

The Institute of Medicine of the National Academies offered up new recommendations for daily intake of vitamin D and calcium late last year. The new Recommended Dietary Allowance (RDA) is 600 IU/day. They define the RDA as “levels of intake that are likely to meet the needs of about 97.5% of the population.” The Upper Level Intake is listed as 4,000 IU/day, which is an increase.

These conclusions are in sharp contrast to the vitamin D zealots of the world, the most aggressive of whom are calling for 5,000-10,000 IU/day to achieve the health benefits of vitamin D sufficiency. I happened to be at the CDC recently for a meeting with some folks very involved in vitamin D research. These are fairly conservative research types (not to be confused with the vitamin D zealots) and the group of renowned epidemiologists was disappointed with the ruling, to say the least. The difference of opinion between the vitamin D research world and the IOM is vast, so let’s break this down, so you can make some reasonable decisions for you, your family, and your patients.

First, let me just say that this is NOT the result of some new study. All of the amazing studies over the past decade on the correlations between vitamin D levels and various diseases are as legitimate today as they were before this release. This is simply the IOM’s attempt to digest all of the studies and make public health recommendations. It is important to understand the public health philosophy at play here. This approach really has little to do with individualized medicine. Consider the following statements the IOM makes:

“An important aspect of Dietary Reference Intake (DRI) development is its grounding in public health applications and the concept of distributions of risk. This approach may appear strange to some and may be disconcerting to those with a clinical orientation who are familiar with the medical model in which the goal is to treat the patient in the most efficacious manner to enhance a positive outcome… This report [is] therefore in contrast to a medical model approach.”

If you’re slow like me you may need to read that again, but let me highlight one point – this report is “in contrast to a medical approach.” A “medical approach” is defined as one “in which the goal is to treat the patient in the most efficacious manner to enhance a positive outcome.”

The above is a HUGE distinction to me. It doesn’t mean I ignore the results of this recommendation or become outraged, but we have to realize that if you are involved in individualized medicine (through a physician or simply in dealing with yourself), the philosophical approach taken here is admittedly different, but this isn’t the most important observation from these recommendations.

The IOM has concluded from their review that there is insufficient evidence to promote vitamin D with respect to its protective properties against anything not related to bone health. That means that all of the interesting and compelling epidemiological studies showing decreased risk for cancers, autoimmune disease, etc did not impress the group enough to affect their recommendations. I personally am compelled by the epidemiology and find it very relevant that risks for some of the most common cancers are reduced by higher levels of vitamin D. Levels that imply protection from colon cancer to autoimmune diseases (to name a few) are realized at levels that greatly exceed what this committee considers acceptable. Remember vitamin D levels required to achieve bone health is considerably lower than the amount it takes to achieve protection against other D-related conditions. If the IOM reached their tipping point and conceded that these other issues are relevant to their recommendations, they would likely be making major jumps in their recommendations.

You can see from their statement below that this committee considers 12 ng/ml to be sufficient for most of the population.

“This committee’s review of data suggests that persons are at risk of deficiency at serum 25OHD levels of below 12 ng/mL. Some, but not all, persons are potentially at risk for inadequacy at serum 25OHD levels from 12 to <20. Unmonitored?

Individual responses to a particular dose of vitamin D differ by a factor of 8! When several people all took the same dose of vitamin D, some folks had their levels go up by only 4ng/ml, whereas some went up by 32ng/ml. The assumption made by IOM that 4,000 IU is the upper max is assuming that nobody is testing their levels. I submit that with testing this is irrelevant. If you are taking 4-10,000 IU/day, you should be testing your levels because you could end up anywhere from 15 ng/ml to over 100 ng/ml depending on your individual response.

I think the efforts by the IOM have clearly been very costly (based on the number of folks involved and the thoroughness of the review), and it is somewhat regrettable that the scope was so narrow.

Vitamin D

IOM's Report: Vitamin D Daily Intake Recommendation

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