You may have heard recently all the news stories that talked about the Institute of Medicine’s (IOM) new guidelines for vitamin D and calcium. These guidelines were updates from those issued in 1997, and the reason for this fuss was that people were surprised and confused by the recommendations related to vitamin D. The message spread far and wide in the media was, “People really don’t need that much vitamin D,” which dismayed many people who’d been using supplements. Worse, some news outlets implied that taking any vitamin D supplements wasn’t just unnecessary, but could even be harmful.
At the heart of the confusion is the fact that these guidelines attempt to establish values for basic nutritional adequacy (meeting the basic needs of 97–98% of the population), not optimum nutrient intake. “Adequate” and “optimum” are very different things — as different as “survival” and “health”! Unfortunately, the way it was presented to the media and the public was “this amount is all you need to be healthy,” and that message just isn’t supported by all of the ongoing research — much of which, sadly, wasn’t included in the IOM’s assessment.
So we at the Center for Better Bones see the current IOM adjustment to the vitamin D Dietary Reference Intake (DRI) as representing both good and bad news. The good news is that we’ve taken baby steps forward in tripling and doubling the RDA (Recommended Daily Allowance) for adults and children and doubling the safe upper level; the bad news is that the message offers false assurance — and maybe even some unnecessary fears — to the general public about their vitamin D intake.
The “baby steps” I referred to are as follows:
1. Raising the Recommended Daily Allowances
The recommendations triple the RDA for individuals age 1 to 70, from 200 IU to 600 IU, and they double the RDA for elderly older than 70 (from 400 IU to 800 IU). I’m thrilled that they recognized that the original recommendations weren’t sufficient, but disappointed that this is as far as they went, given that all the research I’ve seen shows clearly that all people need much, much more than these recommended amounts to be truly healthy.
2. Raising the “Tolerable Upper Limits”
Here again the IOM moved in the right direction: they raised the safe upper limit of vitamin D from 2000 IU to 4000 IU per day for individuals older than 9 years, and also set the upper limit higher for younger children based on their age. We’ve long known that doses over 2000 IU are perfectly safe, and while we often find that even doses above 4000 IU can be beneficial to those who need it, the recommendation moves us forward and confirms the safety of 4000 IU vitamin D for the population as a whole.
Here’s where the IOM missed the boat.
1. Establishing 20 ng/mL as “the level that is needed for good bone health for practically all individuals.”
To put it politely, this conclusion is incorrect. (If I were impolite, I’d call it ridiculous.) In 2009, Bischoff–Ferrari and colleagues published two separate meta-analyses documenting that 20 ng/mL was not sufficient for either fracture or fall reduction. Furthermore, decades of research have established conclusively that the minimal serum 25(OH)D level conducive to bone health is 30–32 ng/mL. It is noteworthy that both the International Osteoporosis Foundation and Osteoporosis Canada support this higher target level for bone health.
2. Basing the vitamin D intake guidelines solely upon the bone health benefits of vitamin D
In their review of the scientific studies, the IOM panel concluded that the evidence supported a role for vitamin D exclusively in bone health. They did not examine a vast body of new research supporting the health benefits of vitamin D because much of it wasn’t the same sort of double-blind, placebo-controlled trials used to prove efficacy of drugs. But there’s plenty of evidence — solid evidence — associating higher vitamin D levels with reductions in the rates of cancer, heart disease, diabetes, multiple sclerosis, and other chronic diseases. These studies clearly indicate that vitamin D levels higher than the minimum required for basic bone health are needed for disease prevention. In fact, a panel of 41 expert vitamin D researchers and medical practitioners has set the evidence-based vitamin D target level at 40–60 ng/mL, a level that we at the Center for Better Bones concur with. But the IOM chose to overlook this data.
3. Concluding that most North Americans are receiving enough vitamin D and need no additional supplementation
This is what’s called “circular logic” — by setting a very low level for vitamin D adequacy (20 ng/mL), of course they conclude that very few people are deficient! Yet vitamin D levels in this country are well below the therapeutic target set by major vitamin D researchers (40–60 ng/mL), and they are declining. According to the NHANES national survey the average vitamin D level has dropped, from 30 ng/mL in 1988–1994 to 24 ng/mL in 2001–2004. The percentage of those below 10 ng/mL has increased from 2% to 6%, and the percentage with levels of 30 or above has decreased from 45% to 23%.
Moving forward — don’t wait another decade for the IOM to catch up
We evolved in abundant sunlight, and our genetic coding reflects the longstanding importance of vitamin D — there are nearly 2800 binding sites for the vitamin D receptor across the length of our genome. A vitamin D level of 40–60 ng/mL would approximate that of our ancestors and — not coincidentally — levels associated with protection from today’s most problematic health issues. Obtaining this more natural vitamin D blood level is easy and safe to do — simply have your vitamin D level tested and then supplement with appropriate vitamin D3 (or sunlight) to reach the target 40–60 ng/mL level. In the end, it’s your health and your life. You could wait another decade for the IOM to seriously review the full scientific data on vitamin D, or you can move forward by raising your awareness and drawing your own conclusions!
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Bischoff-Ferrari, H.A., Willett, W.C., et al. 2009. Prevention of nonvertebral fractures with oral vitamin D and dose dependency: A meta-analysis of randomized controlled trials. Arch. Intern. Med., 169(6), 551–561. URL: http://archinte.ama-assn.org/cgi/content/full/169/6/551 (accessed 12.08.2010).
Bischoff-Ferrari, H.A., Dawson-Hughes, B., et al. 2009. Fall prevention with supplemental and active forms of vitamin D: A meta-analysis of randomized controlled trials. BMJ, 339, b3692. URL: http://www.bmj.com/content/339/bmj.b3692.full(accessed 12.08.2010).
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Ramagopalan, S., et al. 2010. A ChIP-seq defined genome-wide map of vitamin D receptor binding: Associations with disease and evolution. Genome Res., 20 (10), 1352–1360. URL; http://genome.cshlp.org/content/20/10/1352.long (accessed 09.01.2010).