Thursday, October 20, 2011

Vitamin D

By:  Maria



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, thyroid issues, numerous autoimmune disorders, breast cancer, prostate cancer, and colon cancer. Most common, however, are higher risk of the common cold, upper respiratory 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).  An unknown benefit from Vitamin D, is that it regulates insulin secretion and sensitivity and balances blood sugar.  Read here for further information.

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


Supplementation:

If you are deficient from never going out in the sun and never consuming foods rich in Vitamin D, it seems the common recommendation is to have an approximate supplementation of 5,000 IU/day during low-sun exposure season in order to bring Vitamin D levels back to an optimal range. In Utah, this seems to be most definite during the winter months, but even in the summer, it's quite possible and even common, to have a Vitamin D deficiency. A simple blood test will inform you of your Vitamin D levels.  Optimal levels of Vitamin D are 35 ng/mL-60 ng/mL.

Watch this video for more on Vitamin D.


Sources:
Weston A. Price Foundation
Chris Masterjohn
PubMed
Chris Kresser L.Ac

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