Vitamin D recommendations have been raised, but not enough

SupplementsA few weeks ago, the Institute of Medicine (IOM) surprised many of us when it announced its new dietary reference intake (DRI) for vitamin D. The consensus of the scientific community was that the previous DRI of 400 IU was insufficient, and that supplementation with at least 1000 IU would be necessary for most people to achieve vitamin D sufficiency. The IOM disagreed.

The IOM’s new recommendations:

- Recommended intake: 600 IU per day (for children and adults under age 70)

- Tolerable upper limit (amount not to be exceeded in one day): 4000 IU (raised from 2000 IU)

- Sufficient blood 25(OH)D level: 20 ng/ml

There has been a great deal of research in recent years on vitamin D’s role in a variety of human diseases. Low vitamin D status has been associated with cardiovascular disease, certain cancers, cognitive decline, depression, diabetes, pregnancy complications, autoimmune diseases, and even a 78% increase in all-cause mortality risk (<17.8 ng/ml 25(OH)D compared to >32.1 ng/ml). [1] However, because there are not yet enough randomized controlled trials to clearly and conclusively confirm the benefits of vitamin D supplementation for conditions unrelated to bone health [2], the IOM did not find the existing evidence for non-skeletal conditions sufficient enough to raise the daily recommendations any higher than 600 IU. The 600 IU figure is based solely on bone health - they did not take into account whether a greater quantity of vitamin D might be necessary to prevent non-skeletal diseases, even though there are vitamin D receptors in almost every cell of the human body.

Many experts are weighing in on – and disagreeing with – the IOM’s report, and there is general agreement among the experts on these points:

  • The increase of the tolerable upper limit to 4000 IU is a positive change.
  • The IOM’s definition of 20 ng/ml as a sufficient 25(OH)D is potentially low, and this could be dangerous for some people
  • The lack of randomized controlled trials does not mean that we should ignore the epidemiological evidence showing vitamin D’s importance for preventing non-skeletal diseases.

Compare my recommendations to those of the IOM:

Recommendations: 25(OH)D Vitamin D supplementation (adults)
Institute of Medicine >20 ng/ml 600 IU
Dr. Fuhrman 35-55 ng/ml 2000 IU*

*adjust supplementation according to 25(OH)D level

I agree that the IOM’s recommendations are inadequate. My recommendation is a safe, conservative amount of vitamin D which is supported by the literature. To learn more about why following the IOM’s guidelines may be risky, read my full commentary.

 

References:

1. Melamed, M.L., et al., 25-Hydroxyvitamin D Levels and the Risk of Mortality in the General Population. Archives of Internal Medicine, 2008. 168(15): p. 1629-1637.
2. Zhang, R. and D.P. Naughton, Vitamin D in health and disease: Current perspectives. Nutr J, 2010. 9(65).

 

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Comments (6) Read through and enter the discussion with the form at the end
Tamara - December 28, 2010 10:36 AM

Caution is always good, but I do agree that too little is not cautious, it's dangerous! Best bet is to get your Vit D levels checked to know how low you are, and go from there!

StephenMarkTurner - December 28, 2010 6:42 PM

Happy Hols everyone!

What makes me a bit nervous, is that supplementation has been recommended for so many vitamins and such over the years, and I think most have been reduced or retracted (particularly vit A,beta carotene).

In the winter I take more D (1000 most days), but I'm putting a 'low pass filter' on the advice to take that much supplemental D. I'd like to hear more over the next while, let my opinion change slowly if at all.

Regards,
Steve

Stacy - January 3, 2011 2:48 PM

Along with Steve I also am nervous of taking so much of any supplement. I've been reading lately in Nutrition Action that excess vitamin D has been linked to rare cancers such as Pancreatic cancer and others. Any opinions on this?

Deana Ferreri, Ph.D. - January 3, 2011 2:56 PM

In the pancreatic cancer study, the subjects were taking cod liver oil, so the increased risk was likely due to excess vitamin A, not vitamin D.

Beth - January 4, 2011 12:39 PM

I am curious about the risk of higher mortality among women at over 50 ng/ml. Could this be attributed to anything else as well? Such as, too high calcium? My D level was 48, and I thought, wow, to get through winter without flu, it should be a bit higher (I was going to stop supplementing at 60). I was 35 or so before supplementing at all. (Last winter, while pregnant, I went up to 62.)

Thank you.

cara - January 4, 2011 8:54 PM

i have had my levels checked twice in the last 4 mos. one was in aug and it was 18!! then after taking 1,000 IU a day in Nov it was taken again and i was only at a 32. so i was told to take 10,000 IU for 4 weeks and then back down to 5,000 IU a day from then on. my husband takes 1000 IU and our little daughter 500 IU a day- we plan to have their levels checked next mo

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