June 30, 2011

Vitamin D: Are you getting enough?

By Tim Lochhead

For decades, well centuries really, we have been hunter-gatherers and have spent a great deal of time outdoors. Today, many of us are hardly outdoors.

This means less time in the sun.

And this means less time making Vitamin D. (Eventually converted in our bodies from UVB rays).

Is there really a problem? The Life Extension Foundation has a target of 50 ng/mL of 25-hydroxy-vitamin D, and in a recent 2008-2009 study of over 13,000 subjects they found 85% of people did NOT meet this target. (http://www.lef.org/magazine/mag2010/jan2010_Startling-Findings-About-Vitamin-D-Levels-in-Life-Extension-Members_01.htm)

If you recall from our last blog post that Vitamin D is important for bone health, inflammation, aiding against auto-immune disorders and playing a role in the immune system, a deficiency is not good.

So how do we know if we are getting enough?

The most accurate way is of course to check your blood levels. It’s best to ask for the 25(OH)D test, also called 25-hydroxyvitamin D. You can look to get your levels up to at least 30 ng/mL, if not aiming for the 50 ng/ml mark.

Getting enough also ties into sun exposure.

Other sources, like oily fish or fortified milk do not compare to the sun. For example, some oily fish might provide 1,000 IUs per 100 gram serving.

20-30 minutes of summer sun (with about half body exposure) can provide about 10,000 IUs of Vitamin D. This will apply for most of Canada and the US. Amounts will decrease outside of summer months, where supplementing can become very beneficial. If you do supplement, look for D3 (not D2), as this is the natural form we really use.

Everyone’s required exposure for a certain production of Vitamin D varies. Typically, when your skin (without sunscreen, more facts and notes on this next time) becomes a light pink, you have reached your max limit for producing Vitamin D that day. Some fair skinned people may only need 15-20 minutes, while those with darker complexions have a built in SPF, so they need more time. (For some I can hear the cries about sunscreen; again, stay tuned over the next couple of days!)

You are only as strong as your weakest link – don’t let it be Vitamin D!