What you probably learned about vitamin D in school was that it is the “sunshine vitamin” and that you need it for bone health. That is true as far as it goes.
There is now significant controversy among scientific experts, however, over the amounts that are needed for supplementation, the appropriate form of supplement (vitamin D2 or vitamin D3), the accuracy of blood tests and whether supplements are helpful for conditions unrelated to bones. It is no wonder people find this topic confusing.
Q. My wife and I live in Florida. We spend a lot of time outside and get plenty of sun since we both play golf.
All that sunshine should keep us from needing a vitamin D supplement. But after testing our blood levels, our doctor put both of us on a 50,000 IU vitamin D pill once a week.
After two years we are still taking it as our levels haven’t risen much. We are now just barely into the normal range.
A. We are as surprised as you are that your sun exposure hasn’t boosted your vitamin D levels. If you wear sunscreen whenever you are outside your skin may not be making vitamin D.
Questions about Supplements
Your 50,000 IU vitamin pill, a prescription product, is most likely vitamin D2. Although there is some evidence demonstrating that vitamin D2 raises the blood level of 25 hydroxyvitamin D (the metabolite your doctor tested), it may not be as efficient as vitamin D3 (Journal of Clinical Endocrinology and Metabolism, Nov., 2013). Vitamin D2 does not last as long in the body as vitamin D3 (Journal of Clinical Endocrinology and Metabolism, Sept., 2014).
Scientists are rethinking how much vitamin D is necessary on a daily basis. The current recommendation is for 600 IU of vitamin D daily for men up to 70 years of age. A recent review of the vitamin D data, however, proposed a much higher recommended intake level of 7,000 IU per day (Nutrients, March 10, 2015).
