I've been taking a couple of tablespoons of cod liver oil each day, but it was recently brought to my attention that the vitamin A levels in it could be a problem. Could anyone shed some light on this for me? I would really appreciate any input.
asked byKate_6 (416)
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on December 17, 2011
at 04:44 PM
Excess Vitamin A is a problem when you are Vitamin D deficient. Check out this article which discusses this topic - http://chriskresser.com/9-steps-to-perfect-health-4-supplement-wisely
on December 18, 2011
at 08:17 PM
Ummm, I definitely don't agree with Chris Kresser on this topic! (though I like a lot of what he writes...)
Here's another question on the topic: http://paleohacks.com/questions/1096/cod-liver-oil-and-vitamin-a-are-toxic#axzz1guv9AIzw
The ratio of Vitamin A relative to D in all cod liver oil is far greater what we would ever have gotten from our diet during our evolution. Often it is 20:1 and some CLOs may have more.
Think almost-naked living near the equator = 10,000-20,000 IUs Vitamin D per day plus maybe 10,000 IUs Vitamin A per week from liver/organ meats/eggs. So more like a 1:10 A:D ratio would be ideal.
There are other studies from Scandinavia that indicate that excess Vitamin A may compete with Vitamin D receptors and decrease the positive effects of D.
Also, for breastfeeding mothers, Vitamin D levels in the breastmilk do not increase enough to make sure the infant gets enough D from milk until the mother's blood level is at least 50 ng/ml, so his belief that levels over 50 ng/ml are not necessary makes NO sense to me at all. Sorry--I can't find the link to this one right now.