The latest revision of the official vitamin D recommendations were based on the body’s reaction to protect bone health, but what about the other three dozen affected organs?
There are many ways to arrive at a target vitamin level. We’ve already examined some of the problems inherent to just using deficiency disease prevention and evolutionary arguments to establish an optimum intake. If a vitamin only does one thing, then it’s easy, you set the level at whatever the body needs to do one thing best, but what if the vitamin affects dozens of different organs, then it’s more difficult. Here's a list of the target tissues affected by vitamin D. In revising their recommendations, the Institute of Medicine decided to only look at one tissue, bone, which many considered to be a mistake.
I did like how they went about it, though. They asked the expert: the human body. When our body senses we don’t have enough active vitamin D for adequate bone health it releases a hormone, called PTH, to boost our levels. And so the Institute of Medicine figured why don’t we just listen in on the body’s own innate wisdom and find out which level of vitamn D it feels comfortable with for bone health. And that number is about 20 ng/ml, here as 50 nanomole per liter. Once we fall below that our body is like uh, oh, and starts producing this PTH to protect our bones from softening. But that’s just the bone; what about the other 3 dozen organs affected by vitamin D?
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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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 seventh video in a nine day series on vitamin D. Be sure to check out yesterday's video-of-the-day The difficulty of arriving at a vitamin D recommendation.
For additional context check out my associated blog posts: Vitamin D: Shedding Some Light on the New Recommendations and Vitamin D from Mushrooms, Sun, or Supplements?