Have you had your Vitamin D levels checked recently? Current research is showing that optimizing your vitamin D levels could be one of today’s most important preventative medicine strategies. Once thought to only influence calcium, phosphorous, and bone metabolism; Vitamin D is now being shown to have a much wider range of activity. Research shows that it plays a role in infections, autoimmune diseases, cardiovascular disease, and even various forms of cancer (N Engl J Med 2007; 357:266-281). As it turns out, rickets is really only the tip of the vitamin D deficiency iceberg.

In 1980, an unprecedented study hypothesized Vitamin D’s role in cancer. Two researchers from the Moore Cancer Research Center (USD San Diego) studied colorectal and breast cancer rates in 15 countries across the globe. They incorporated measurements of serum vitamin D3 levels and satellite measurements of cloud cover and sunlight into the study. The results clearly showed an inverse correlation between sunlight exposure and incidence of cancer. Countries like Europe and North America where solar radiation is less intense had a 4-6 times higher incidence of cancer.

Since then, the amount of evidence supporting Vitamin D’s anti-cancer properties continues to mount. Recently, Lappe et al reported the first double-blind, randomized, interventional trial of vitamin D. Women over the age of 55 who took a 1,100 IU/day vitamin D supplement were shown to have a 75% reduction in breast cancer compared to placebo (Am J Clin Nutr 2007; 85: 1568-1591).

Vitamin D isn’t really a vitamin, but rather a hormone made by the skin under direct exposure to the sun’s UVB rays. Vitamin D targets over 200 genes in a wide variety of tissues. It inhibits cancer by: destroying aberrant cells before they become cancerous, by promoting cell differentiation, and by reigning in of out of control cell growth.

Vitamin D deficiency is a growing epidemic throughout the world, and it is thought that up to 70% of North Americans could be deficient. The current RDA values for vitamin D supplementation are based upon levels needed to prevent bone diseases - but not cancer, cardiovascular disease, MS, or influenza. Very little vitamin D is present in our food except for oily fish - salmon, mackerel, sardines, and cod liver oil. Blood levels of 25-hydroxyvitamin D are the barometer for assessing deficiency. Experts are considering optimal levels to run in the range of 50-99 ng/ml, levels below 20 ng/ml are considered deficient.

There are 3 ways to treat vitamin D deficiency: sunlight, safe artificial UVB radiation, and appropriate supplementation with vitamin D3. Regular, short intervals of sun exposure in which a large portion of your skin is exposed (over 40% of your body) is the most effective method for raising vitamin D levels. In caucasian skin, it takes about 20 min to reach the maximum production of vitamin D. Caution should of course be taken to avoid burning by gradually increasing exposure time. Pigmented skin will require significantly longer sun exposure for producing vitamin D - an estimated 3-6 times longer. Supplementing with vitamin D3 should be done according to blood levels, and the amounts required to treat deficiency may very well be doses that make many physicians uncomfortable.

So, for prevention’s sake, if you haven’t gotten your vitamin D levels checked yet, consider getting an end of winter baseline to learn just how much supplementation your body requires.

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