Friday, November 20, 2009

Vitamin D Confusion

Until recently, I'd never given vitamin D much thought. I mean, rickets? Isn't that a disease that pirates and other seafarers got, along with scurvy and beriberi? It seems like every time I turn on the news lately, vitamin D deficiency is linked with other health conditions, such as cardiovascular disease, prostate cancer, diabetes, depression, even H1N1 influenza. The problem isn't limited to adults, either. New research has indicated that children are vitamin D deficient as well.

It's possible we've taken the "safe sun" message too much to heart. We've become so accustomed to slathering on sunscreen every time we step outside that we're blocking our bodies' natural vitamin D production from the UV light of the sun. Ironic that by trying to prevent one disease, skin cancer, we've potentially put ourselves in the path of other diseases.

The NIH recommends 400 IU of vitamin D supplementation for adults, assuming an individual is not synthesizing any vitamin D from sunlight. But is that enough? Recent evidence makes the case for higher amounts, up to 5000 IU per day. There is also a case for modest sun exposure, 5-10 minutes of full sun (without sunscreen) on the arms/legs/face, 2-3 times per week. But the amount each individual needs varies based on age, race, time of year, and latitude. So how to know if you're getting enough?

I was surprised to learn recently that a simple blood test can tell you if you're getting enough vitamin D. (And with my annual physical coming up in a couple of weeks, I'm definitely asking for my D to be tested as part of my labs.) If you'd like to ask for it too, it's the 25-hydroxyvitamin D test, also known as the 25(OH)D test. Note: This is different from the 1,25-dihydroxyvitamin D test [1,25(OH)2 D], which will not give an accurate portrayal of vitamin D status. According to the Vitamin D Council, a healthy level is 50-80 ng/ml, which should be maintained year-round.

Another bit of information of note: Athletes may need more vitamin D than the general population. This is an area of research that needs more study, but initial recommendations are on the upper end of the intake range. One writer chronicled her experience with D deficiency and its effects on her athletic performance. If your performance has been lagging for no apparent reason, it might be time to check your D level.

I think this is as good a reason as any for me to pack it in and move to the Caribbean. "Sunshine Vitamin" anyone?

1 comment:

  1. vitamin d is the ninja vitamin.
    ill move with you down paradise way, but im more afraid of hurricanes than i am fake baking a few times a year.

    good article on other benefits of vitamin d:

    great site!