I've been experimenting with A and D intake for about 7 years. My D levels are maintained in the middle of the reference range, per labcorp or ZRT at 65 ng/mL. For me, this requires 6,000 IU D per day. I've experimented with A intakes from 3-4x my D intake per day, down to my current 1/6th. At 20-25,000 IU A per day, I over time developed symptoms of A toxicity, especially excessively dry skin, lips and mucous membranes. Over time, I tracked serum A levels and supplementation, finally settling where I am now, at 1,000 IU preformed (not beta arotene) A intake per day.

In an evolutionary environment, it seems highly unlikely that we could have acheived A intakes of 20,000 IU per day which is what Masterjohn and the WAPF recommend. Nor would we have had access to high vitamin cod liver oil. The liver is just one small part of an animal...one part that would have been shared among (likely) many people and would have been eaten in ratio to the rest of the animal, including the fat, muscle meat, other organs, bone marrow, brains and blood. My perception is that a daily high intake of retinol just wouldn't have been possible.

ambimorph,

Here is some current info from Masterjohn's blog at the WAPF page:

http://www.westonaprice.org/blogs/cmasterjohn/2012/01/22/new-evidence-of-synergy-between-vitamins-a-and-d-protection-against-autoimmune-diseases/

good question. i'm just now experimenting with different dosages of retinol (supplement made from from cod liver), while keeping my usual intake of D3 (10'000IU/d) steady. result so far: even at a relatively moderate 20'000IU/d, i already get some of the typical side effects like reduction of activity in frontal cortex, lethargy, slight problems with visual and muscular coordination, depressive mood, which all are described in the literature about retinoids. even at 10'000IU those effects are perceptible as well, but just barely. luckily, these effects go away a few hours after taking it. not quite sure how to interpret this. could be, that my A status is already "full" and therefore i'm overdosing even with the otherwise harmless "UL" amount of 10k, or it could be that i am deficient, and those symptoms are just an indicator of "filling up" my retinol stores. i'm now backing down to 5k and see what happens with time :) (of course, one could always do a blood test. not sure how reliable this is for determining vitamin A status tho).

And there is this posting out of the Vitamin D Council regarding Vit A being antagonistic to Vit D.

http://www.vitamindcouncil.org/PDFs/cannell-et-al-vitamin-d-deficiency-epidemic.pdf

The study out of Annals of Otology, Rhinology & Laryngology 117(11):864-870. says that they cannot recommend the use of CLO.

A meta-analysis concluded that vitamin A, when given alone, slightly increased the incidence of respiratory tract infections.46 If vitamin A increases the risk of respiratory infections by antagonizing the action of vitamin D, its high content in modern cod liver oils will mask the benefit of adequate vitamin D nutrition. As the prevalence of vitamin A deficiency in the United States — but not in the Third World — is much lower than the prevalence of subclinical vitamin A toxicity,47 we cannot recommend cod liver oil or even multivitamins with preformed retinol (retinyl palmitate and retinyl acetate) for either adults or children. (We exclude fish body oil from our warning, as it contains no vitamin A — or vitamin D — but is a very important source of omega-3 fatty acids.)

Even though I have the highest respect for Sally Fanon, Chris Masterjohn, and the WAPF, Fanon's comment in a Sean Croxton interview threw me for a bit of a spin. She said raw milk consumption has been going on for tens of thousands of years and is not only safe, but for everyone. I could be wrong but I thought the domestication of animals has only occurred for approximately LESS THAN ten thousand years? Maybe it's just my bitter sentiment to my lactose-intolerance that's talking...

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