Monday, January 28, 2013

Nutritional Vitamin D

I see so many misconceptions stated in articles that a person can get sufficient Vitamin D through diet. This is simply not true.  Check this out from an article about how to get every vitamin through food sources:

Why you need it: Vitamin D, which our body generates on its own when our skin is exposed to sunlight, helps spur calcium absorption and bone growth. It's also important for cell growth, immunity, and the reduction of inflammation.
Where to get it: Fatty fishes—including swordfish, salmon, and mackerel—are among the few naturally occurring dietary sources of vitamin D. (Cod liver oil is tops, with 1,360 IU per tablespoon, while swordfish is second with 566 IU, or 142% DV.) Most people tend to consume vitamin D via fortified foods such as milk, breakfast cereals, yogurt, and orange juice.
Good information, however, it doesn’t really tell you that you can’t get ENOUGH Vitamin D by simply eating these foods. The “142% DV” part is inaccurate; it leads the reader to believe that 566 IU of Vitamin D is adequate. While there is not really a clear or consistent RDA that seems to be agreed upon depending on your research, I feel the evidence of the epidemic of Vitamin D deficiency would need to be taken into consideration here. If the RDA listed here of 566 IU were a sufficient level for a person with an already healthy Vitamin D level, it would make sense that for a person that is deficient, they would need a higher intake.
How about some math to make my point?

To go from 20 ng/ml to 40 ng/ml would require an average additional intake of 2600 IU/day. So that would mean taking in 3166 IU per day. Considering that a 20ng/ml level is actually average (and well below the recommended range of 40-60ng/ml) for the US, the statement that 142% DV is misleading. So how much fatty fish and cod liver oil do you want to eat every day?

Now take a look at these numbers for comparison.

UVB Exposure
Natural Sunlight – 10,000 – 20,000 IU per day, in summer, 10am – 2pm
Tanning Bed with UVB – 10,000 IU per session
Salmon – fresh, wild, 3.5 oz – 400 – 1000 IU
Salmon – farmed, 3.5 oz – 100 - 250 IU
Fortified Milk – 8 oz – 100 IU
Vitamin D3 – from 400 – 1,000 IU in tablets or liquid

So what seems like the most effective and efficient source of Vitamin D? THIS is why it is important to know your level, and know how much Vitamin D you are getting. 

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