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New IOM vitamin D recommendations - baby steps and missteps

In late November 2010, the Institute of Medicine (IOM) released its new guidelines for vitamin D and calcium, updating them from 1997. While the recommendations for calcium intake showed little change, the recommendations for vitamin D were modestly increased — yet not nearly as much as the burgeoning research in vitamin D warrants. Unfortunately, even this incremental progress was undermined by the IOM’s misguided assertion that the minimum serum vitamin D level should be lowered.

At the Center for Better Bones and the Better Bones Foundation, we realize these guidelines attempt to establish values for basic nutritional “adequacy” (meeting the basic needs of 97–98% of the population), not optimum nutrient intake. The news is good in some ways and not so good in others. We see the current IOM adjustment to the vitamin D Dietary Reference Intake (DRI) as representing both baby steps forward and detrimental missteps.

Take two baby steps forward

1.  Raising the Recommended Daily Allowances

» Tripling the RDA for individuals age 1 to 70, from 200 IU to 600 IU

» Doubling the RDA for those 71 and older, from 400 IU to 800 IU

» Doubling the recommendation for infants from birth to 1 year, from 200 IU to 400 IU per day

Raising the RDAs for all age groups is a step in the right direction. However, the new amounts recommended are still in most cases far less than those needed to reach an optimum, health-promoting vitamin D status.

2. Raising the “Tolerable Upper Limits”

» Doubling the Upper Limit (UL) for individuals age 9 and older, from 2000 IU to 4000 IU per day

» Setting the UL for infants 0 to 6 months at 1000 IU; 6-12 months at 1500 IU; children 1-3 years at 2500 IU; and children 4-8 years at 3000 IU per day

Raising the Tolerable Upper Level Intake (the highest average daily intake likely to pose no risk of adverse effects to almost everyone in the population) moves us forward and confirms the safety of 4000 IU vitamin D for the population as a whole. While this is an incremental step forward, preeminent vitamin D researchers worldwide find ample evidence for a UL of 8000–10,000 IU. Furthermore, many people have such low vitamin D levels that they need more than 4000 IU daily to restore and maintain adequate vitamin D reserves.

As an anthropologist giving these Upper Level guidelines consideration, I find it interesting to note that healthy adults utilize approximately 3000–4000 IU of vitamin D every day,1 and that we have an enormous capacity to produce vitamin D upon sunlight exposure. For example, in 20 minutes on a sunny beach an average fair-skinned adult can produce at least 10,000 IU of vitamin D2 (dark-skinned people take longer to produce the same amount).

Now for the IOM’s missteps

1.  Establishing 20 ng/mL as “the level that is needed for good bone health for practically all individuals”

We at the Center for Better Bones find this conclusion to be erroneous, and submit that the minimal serum level 25(OH)D level conducive to bone health is on the order of 30–32 ng/mL. Our assertion is substantiated by a number of clinical trials, as discussed in our 2008 vitamin D fracture studies review,3 as well as various meta-analyses. In 2009, for example, Bischoff–Ferrari and colleagues published two separate meta-analyses documenting that 20 ng/mL was not sufficient for either fracture4 or fall reduction.5

As noted osteoporosis researcher Dr. Robert Heaney recently commented, “Fracture reduction does not reliably occur at levels less than 30 ng/mL and in some cases as high as 40 ng/mL. Osteoid seam width, a measure of vitamin D deficiency, only reaches normal values when the level is above 30 ng/mL.”6 Finally, it is of note that both the International Osteoporosis Foundation7 and Osteoporosis Canada8 support 30 ng/mL as the 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. The vast body of new research supporting the health benefits of vitamin D for a reduction in the incidence of various cancers, cardiovascular disease, hypertension, diabetes, metabolic syndrome, falls, immune response, autoimmune disease, and the like were deemed inconclusive and unreliable. Thus, the IOM panel chose to base its new vitamin D reference intake solely on their evaluation of the role that vitamin D plays in bone health.

This is an unfortunate misstep for several reasons. Most importantly, it flies in the face of mounting documentation of multiple, life-supporting health benefits of higher vitamin D levels. A colorful graphic representation of these data (see www.grassrootshealth.net) has been compiled by distinguished vitamin D scientists Drs. Cedric Garland and Carole Baggerly.

Secondly, dismissing the new non-bone vitamin D research allowed the IOM to set a much lower apparent level of adequacy. Numerous studies on cancers, heart disease, diabetes, multiple sclerosis, and other diseases clearly indicate that vitamin D levels higher than the minimum required for basic bone health are needed. 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.9 We at the Center for Better Bones concur with the target level.

3.  Concluding that with a few exceptions all North Americans are receiving enough vitamin D and need no additional supplementation

Only by setting a very low level for vitamin D adequacy (20 ng/mL) could the IOM make this statement. 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%.10

Moving forward — don’t wait another decade for the IOM to catch up

We evolved in abundant sunlight: Our genetic coding reflects the longstanding importance of vitamin D, with nearly 2800 binding sites for the vitamin D receptor across the length of our genome. Further, vitamin D is documented to influence the expression of some 229 genes,11 and the emerging research links higher levels of vitamin D with reduced incidence of numerous diseases. Obtaining 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.12 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.

Finally, knowledge is power. If you are concerned about maximizing your health and enhancing disease-free longevity you might want to keep abreast of the leading-edge vitamin D research. One easy way to do this is to keep in touch with public-interest vitamin D advocacy groups at Grassroots Health (www.grassrootshealth.net) and the Vitamin D Council (www.vitamindcouncil.org). It’s your health and your life. You could wait another decade for the IOM to seriously review the new scientific findings of vitamin D, or you can move forward by raising your awareness and drawing your own conclusions!

Susan E. Brown, Ph.D.
The Center for Better Bones
The Better Bones Foundation  

1 Heaney, R.P. et al. 2003. Human serum 25-hydroxycholecalciferol response to extended oral dosing with cholecalciferol. Am. J. Clin. Nutr., 77 (1), 204-201. URL: http://www.ajcn.org/content/77/1/204.full (accessed 12.08.2010). 

2 [No author or date of publication listed.] Understanding vitamin D cholecalciferol. URL: http://www.vitamindcouncil.org/ (accessed 12.08.2010).

3 Brown, S.E. 2008. Vitamin D and fracture reduction: An evaluation of the existing research. Alt. Med. Rev., 13 (1), 21-33. URL: http://www.thorne.com/altmedrev/.fulltext/13/1/21.pdf accessed 12.08.2010).

4 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).

5 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).

6 Heaney, R., 2010. As quoted at “Grassroots Health. Vitamin D action — IOM Bone Health.” URL: http://www.grassrootshealth.net/iombonehealth (accessed 12.08.2010).

7 Dawson-Hughes, B., et al. 2010. IOF position statement: Vitamin D recommendations for older adults. Osteoporos. Int., 21 (7), 1151–1154. URL: http://www.springerlink.com/content/nn0577u6826418w7 (accessed 12.08.2010).

8 Papaioannou, A., et al. 2010. Clinical practice guidelines for the diagnosis and management of osteoporosis in Canada: Summary. CMAJ, 182 (17), 1864–1873. http://canadianmedicaljournal.ca/cgi/content/full/182/17/1864 (accessed 12.08.2010).

9 Baggerly, C. 2010. Grassroots Health | Vitamin D action – GRH Recommendations. URL: http:// grassrootshealth.net/recommendation  (accessed 12.08.2010).

10 Adit, A., et al. 2009. Demographic differences and trends of vitamin D insufficiency in the US population, 1988-2004. Arch. Intern. Med., 169 (6), 626–632. URL: http://archinte.ama-assn.org/cgi/content/full/169/6/626 (accessed 12.08.2010).

11 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).

12 Vieth, R. 2001.Would prehistoric human 25-hydroxyvitamin D concentrations be beneficial, and how much vitamin D do we need to ensure desirable nutritional targets? In Nutritional Aspects of Osteoporosis, eds. P. Burckardt, et al. San Diego: Academic Press.