Transcript: Vitamin D and Mortality May Be a U-Shaped Curve
The Institute of Medicine raised their vitamin D recommendations, based on a blood level target of 20 [nanograms per milliliter], to prevent bone-softening disorders, such as rickets. Although the Institute’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, let’s 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’s recommendation, 20 ng/ml (which translates to the 50 nanomoles per liter you see here). Here’s 30  and this is 40 .
So for longevity, around 30 would seem a better 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 to 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.
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