Two weeks ago I warned you about excessive sun exposure.  Ironically, this week I’m warning you about a consequence of insufficient sun exposure.

A recent article in the New England Journal of Medicine exposes a very common and under-diagnosed problem, vitamin D deficiency.  This has become a bigger problem as our activities have moved increasingly indoors, and is even more common in Europe where food fortification with vitamins is rare.  The article cites studies that show that more half of post menopausal women taking medications for osteoporosis are deficient in vitamin D, and children and young adults are frequently deficient as well.

The effects of vitamin D deficiency on bone health are well understood.  Vitamin D deficiency leads to osteoporosis and in extreme cases to rickets.  Vitamin D is also essential to muscle function, and an intriguing study a couple of years ago also linked vitamin D deficiency to an increased frequency of falls in the elderly.  The article also cites many other studies that implicate vitamin D deficiency in a host of other diseases, from heart disease to colon cancer.  Most of these studies are observational, not experiments, so I’m not prepared to accept that vitamin D deficiency causes everything from bubonic plague to inflation, but the widely accepted effects on bone health and falls are reason enough to take it seriously.

There are two important points to take away from the article.  The first is that vitamin D deficiency is very common and easily diagnosed with a blood test called 25-hydroxyvitamin D.  The second is that the current dietary guidelines for vitamin D are likely insufficient and that everyone should be encouraged to get at least 800 IU of vitamin D daily.  For post-menopausal women who have been encouraged to take calcium and vitamin D supplementation, that will likely mean switching to a supplement with more vitamin D.  For example, Oscal + Extra D has 500 mg of calcium with 400 IU of vitamin D, so taking one tablet twice a day would give 1 gram of calcium with 800 IU of vitamin D.

(Thanks to my partner, Dr. Rubencio Quintana, for brining this article to my attention.)