In Chris Masterjohn's review of The 4 hour body, he quotes Tim Ferris as saying:
Supplemental vitamin D increases your need for vitamin A, so don't forget the aforementioned cod liver, which includes both.
Does anyone know of evidence for this?
(I've already heard lots of argument on both sides in the other direction, i.e. that vitamin A may interfere with vitamin D.)
asked byAmbimorph (18706)
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on December 16, 2010
at 08:59 PM
Aha, I just found this: Is Vitamin D Safe? Still Depends on Vitamins A and K! Testimonials and a Human Study. I should have known he wouldn't leave us up in the air with that. There's a lot there, and I haven't read it all yet, but it seems a good place to start.
on December 17, 2010
at 04:49 PM
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.
on January 27, 2012
at 06:55 PM
Here is some current info from Masterjohn's blog at the WAPF page:
on December 17, 2010
at 01:47 PM
And there is this posting out of the Vitamin D Council regarding Vit A being antagonistic to Vit D.
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.)
on December 17, 2010
at 11:48 AM
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).
on January 07, 2015
at 07:00 PM
I have had been feeing dreadfully depressed the last few months. Doesn't seem situational, more chemical. I've supplemented with 10,000IU D nightly for three years. Only other supplements are some calcium before bed (induces REM sleep), magnesium, chromium, and B/C.
Took a 10,000 A/retinol last night. Slept like the dead. Woke up this morning noticably even feeling and a complete lack of the usually pronounced 'any time I'm awake' depression feelings.
Just before, and during my morning coffee, I was already happy and in a good, if even, mood, and it became noticable that, while coffee usually is my hour or two of good feelings lately, I was already happy and coffee didn't change anything.
So noticeable that I started to wonder what I did differently It took a while to even consider A as that isn't normally associated with depression.
After a lot of searching, Ive been to WAPF and seen how too much D without A depleted A and causes D toxicity symptoms. I've not felt any of the other D toxicity symptoms, but I'll be damned if that A didn't have a huge impact.
on April 19, 2012
at 05:55 PM
What exactly is the capability of significant vitamin A?
Whilst vitamin A is most commonly known for it's crucial part in eye sight, this particular vitamin even takes part in bodily functions connected with the disease fighting capability, servicing of epithelial and even mucous tissue, development, reproduction, along with bones development. When it comes to foods, vitamin A frequently comes up as a fats element generally known as retinyl palmitate. The body system changes retinyl palmitate to 3 metabolically dynamic sorts of that essential vitamin: retinol, retinal, as well as retinoic acid.
Works with Perspective
Commonly the person's retina incorporates 4 sorts of photo-pigments which put away vitamin a deficiency. One of these simple pigmentation, generally known as rhodopsin, is situated in the rod body cells of the retina. Rhodopsin permits the rod cells to find minimal concentrations of lumination, as well as, as a result, takes on a essential position in the adapting of the eyeball to low light environments as well as night time eyesight.
Retinal, the actual aldehyde type of the particular necessary vitamin, takes part in the production of rhodopsin, plus in the collection of compound side effects which induces visible excitation, which can be activated from illumination hitting the rod cells. The actual additional 3 pigments, jointly generally known as iodopsins, are located on the cone cells of the retina and so are in charge of day time eye-sight.
on April 24, 2011
at 04:13 AM
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...
on December 17, 2010
at 02:41 PM
I don't think WAPF would countinuously defend their position on the Vit A+D benefits of FCLO if there were none... There has to be more to this.
on July 11, 2012
at 02:51 PM
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