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Vitamin D and Mortality May Be a U-shaped Curve

Vitamin D deficiency may shorten one’s lifespan, but getting too much vitamin D may also adversely affect longevity.

December 8, 2011 |
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Vitamin D and Mortality May Be a U-shaped Curve, 5.0 out of 5 based on 2 ratings

Sources Cited

Institute of Medicine (US) Committee to Review Dietary Reference Intakes for Vitamin D and Calcium. 2011.

Holick MF. Vitamin D: extraskeletal health. Endocrinol Metab Clin North Am. 2010 Jun;39(2):381-400.

Michaëlsson K, Baron JA, Snellman G, Gedeborg R, Byberg L, Sundström J, Berglund L, Arnlöv J, Hellman P, Blomhoff R, Wolk A, Garmo H, Holmberg L, Melhus H. Plasma vitamin D and mortality in older men: a community-based prospective cohort study. Am J Clin Nutr. 2010 Oct;92(4):841-8. Epub 2010 Aug 18.

Acknowledgements

Transcript

The Institute of Medicine raised their vitamin D recommendations based on a blood level target of 20 (ng/ml) to prevent bone softening disorders such as rickets. Although the Institite’s target of 20 may “prevent the overt skeletal deformities associated with rickets, there is now,” according to a review last year, “overwhelming and compelling data suggesting that the human body requires a blood level of above 30 ng/mL for maximum health.” Dr. Holick bases this assertion on data like this, a graph not of rickets risk, but of colon cancer risk versus vitamin D levels suggesting that the Institute of Medicine’s 20 is good, but 30 or more may be even better if you’re considering vitamin D from the cancer prevention angle instead of just strictly skeletal health.
There are similar graphs for breast cancer risk, multiple sclerosis and other conditions linked to vitamin D status. Instead of going through each lets just jump straight to total mortality. What blood level of vitamin D will enable us to, on average, live longest? Here’s the graph, and as you can see, it’s kind of a U shaped curve.
Not having enough in our bloodstream is associated with higher mortality; but looks like we can have too much as well. So what’s the sweet spot in the middle, the lowest mortality risk? This is the Institute of Medicine recommendation, 20 ng/ml (which translates to the 50 nanomoles per liter you see here). Here’s 30 (75) and this is 40 (100).
So for longevity, around 30 would seem the best target. So one strategy to arrive at a vitamin D recommendation would be to figure out how much sun and/or supplements we might need take to get our levels to 30.

To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring watch the above video. This is just an approximation of the audio contributed by veganmontreal.

To help out on the site please email volunteer@nutritionfacts.org

Dr. Michael Greger

Doctor's Note

Please feel free to post any ask-the-doctor type questions here in the comments section and I’d be happy to try to answer them. This is the fourth video in a nine day series on vitamin D. Be sure to check out yesterday's video-of-the-day Is vitamin D the new vitamin E?.

Also, check out my associated blog posts: Eating To Extend Our Lifespan andVitamin D: Shedding Some Light on the New Recommendations.

  • http://nutritionfacts.org/members/mgreger/ Michael Greger M.D.

    Please feel free to post any ask-the-doctor type questions here in the comments section and I’d be happy to try to answer them. This is the fourth video in a nine day series on vitamin D. Be sure to check out yesterday’s video-of-the-day Is vitamin D the new vitamin E?.

  • http://nutritionfacts.org/members/jms/ jms

    Are the mortality factors that increase with higher Vitamin D levels related to sun exposure, e.g. skin cancer? If so, I wonder whether higher levels obtained via supplementation would imply the same risk.

    Also, considering the increased risk of mortality from higher Vitamin D levels, how did the Institute of Medicine derive an upper daily limit of 4000 I.U. per day?

    • http://nutritionfacts.org/members/drdons/ DrDons

      Hi JMS, The studies track all case mortality and some focus further on deaths due to CV disease and cancer the latter would include skin cancer but they make up only a small number. The recommendations that come out of “expert committees” based on “consensus” have been shown to be highly variable and not very good even when not influenced by industrial/pharmaceutical ties so they have to be viewed as one piece of information. You don’t have to worry about the upper limit if you don’t take supplements. Dr. Gregers Dec 9 video does a great job at demonstrating how complex this issue is. You might enjoy reading John McDougall’s article in his March 2011 Newsletter available on his website entitled, Vitamin D:Values for Normal are Exaggerated. As shown in a study mentioned by Dr. Greger even life guards don’t often meet the recommended levels. So I don’t recommend Vit D supplements except in cases where patients can’t get sun light or have repeat values below 20 after attempts to increase by sun exposure. The other thought is that I wouldn’t be surprised if some day we discover other chemicals that are released by our skin when exposed to sun light… a good reason to stay tuned to Nutritionfacts.org for the latest science. It is clear at this point that sun light exposure on a regular basis is important to our health.

  • http://nutritionfacts.org/members/2rhealth/ 2RHealth

    In reading the details in the article you referenced on the U-shaped curve, I was interested to see those in the 90th percentile had a vitamin D level of >37ng/mL and the lowest 10 percent were <18ng/mL. Neither of these groups had much different dietary intake or supplementation than others in the study. Looks like much of the difference is genetic! The only variable that appeared different is a slightly higher percentage of the 90th percentile group had blood samples taken in the June-November time period, although they did not find this a significant confounding variable. Conclusion – some of us may have high vitamin D, even without supplementation! Should we get tested to make sure we don't overdose?

  • http://nutritionfacts.org/members/drdons/ DrDons

    Hi 2RHealth, I don’t think you are in danger without taking supplementation. Dr.Gregers series of videos does justice to demonstrating how complex this issue is and how much variability there is within a population. It is good that the institute of medicine is looking at a variety of ways to help sort this out such as using the pharmacokinetics: http://nutritionfacts.org/videos/resolving-the-vitamin-d-bate/ although we have no good way to measure storage. It is a very complex area with concerns about recommending isolated nutrients see http://nutritionfacts.org/videos/is-vitamin-d-the-new-vitamin-e/ and involving a fat soluble vitamin which can lead to toxicity. Throwing around terms like “optimal” levels is misleading for many reasons when dealing with complex systems. In my opinion when making recommendations that potentially effect 40 per cent of the population I believe caution is in order. For me as a physician patients should be encouraged to get regular sun exposure which varies according to latitude see http://nutritionfacts.org/videos/vitamin-supplements-worth-taking/ and for me I would accept Vit D levels are in the 20 -30 range. For patients with minimal sun exposure Dr. Gregers recommendation of 2000/day is reasonable.

  • Michael Greger M.D.

    For some context, please check out my associated blog post Vitamin D: Shedding Some Light on the New Recommendations!

  • David Hollenberg

     In a recent paper “Vitamin D an Pancreatic Cancer Risk – No U-Shaped Curve”,
    the authors say that the U-shaped curve is most likely a statistical artifact and
    that there is no U-shaped curve to be explained.  See
    http://ar.iiarjournals.org/content/32/3/981.full .

  • Kartoffelmao

    2000IU or 50mcg every day is just enough to get in the range around 30ng/ml or 80nmol/l levels longterm. This is what study after study shows us.

  • Amanda

    My vitamin D was 18.9 and the range goes from 30.0-100.0 ng/mL
    So seriously deficient… I live in Belgium, we don’t get much sun. So I supplement. Everyone is deficient here

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