Friday, February 26, 2010

Vitamin D

Technically not a "vitamin"; vitamin D is in a class by itself. Its metabolic product, calcitriol, is actually a hormone that targets over 2000 genes (about 10% of the human genome) in the human body. Vitamin D is essential for promoting calcium absorption in the gut.

85-90% of people are deficient to severely deficient in Vitamin D. This is because we get very little from our diets except for fish and in fortified dairy. Much of this is heightened by the fact that many of our jobs are indoors and when we do venture outdoors, we use sunscreen which blocks UVB radiation that allows Vitamin D production to occur in our skin. Getting our Vitamin D from the sun becomes difficult during winter season, when we spend the majority of our time indoors.

Deficiency in Vitamin D is associated with diseases such as rickets, breast cancer, prostate cancer, and colon cancer. Most common, however, are higher risk of the common cold, upperrespiratory infections, influenza,childhood asthma and pneumonia.

The health benefits of Vitamin D are numerous, but include bone health, cardiovascular and cholesterol health (there are studies showing a decrease in cholesterol during summer months, when we are more apt to get outdoors in the sunshine).

As well all know, modern diets in the US are pro-inflammatory due to the large amounts of unfavorable carbohydrates that we eat. Vitamin D reverses those effects and improves inflammatory response.

There is a large amount of evidence from studies implicating optimal Vitamin D levels and athletic performance - something we all strive for.
Food sources:

International Units(IU)/per serving
Pure Cod liver oil, 1 Tablespoon /1,360 IU
Salmon, cooked, 3½ ounces /360 IU
Mackerel, cooked, 3½ ounces /345 IU
Sardines, canned in oil, drained, 1¾ ounces /250 IU
Tuna fish, canned in oil, 3 ounces /200 IU
Milk, nonfat, reduced fat, and whole, vitamin D fortified, 1 cup /98 IU
Egg, 1 whole (vitamin D is found in egg yolk) /20 IU


If you are deficient from never going out in the sun and never drinking or eating dairy, it seems the Vitamin D Council recommends that having an approximate supplementation of 5,000 IU/day during low-sun exposure season, is necessary to bring Vitamin D levels back to an optimal range. A simple blood test will inform you of your Vitamin D levels.

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