It sounds like there is a good possibility that anyone with elevated homocysteine may have problems retaining Vitamin A as homocysteine may destroy it. At least there is evidence of such a problem with the CBS gene and it is theorized to be due to homocysteine. I posted this under the CBS topic but it may be of general interest:
I have not proven it but I believe I have a problem with Vitamin A of some sort. I just ran across something of interest in this regard. It appears that CBS (or possibly anything that raises homocysteine) can destroy Vitamin A:
Phyllis Acosta in "Nutrition Management of patients with inherited metabolic disorders" says that CBS deficiency may impair Vitamin A status as Vitamin A was found low even after retinol administration. She theorizes homocysteine may oxidise Vitamin A. There is more discussion that I cannot get as the books costs $246. (She begins to discuss elevated plasma copper -- something which indicates inflammation, not high copper stores...).
She later discussed protein requirements in PKU and PEM...too bad I can't read them. I found elsewhere that in malabsorption the protein requirement goes up (to make up for what is undigested) - 30% or more depending on the degree of malabsorption.
For me, I keep getting low ferritin (well a few times a year) and low ferritin causes hypothyroid (for me - but my ferritin goes below 20, maybe lower as it makes me gasp for air). This last time was because I stopped my multi which has iron in it...and yet I am over 50 and should not need to supplement iron, and I eat about as much protein as my friends who do not have these issues.
I find ferritin is bound by RBP (retinol binding protein), and I cannot reaise ferritin sufficiently (supposed to be 70, but at least above 50, mine has never been above 47, and anything above 40 causes raised serum Fe (bad). I have several signs of low Vitamin A -- keratinus pilaris (which a college textbook on line said was a Vitamin A deficiency) and a loss of enamel along the tops of my teeth which occurred at 18 when my mother switched to low fat milk (maybe 1/2percent...I am not sure if the lowfat milk was supplemented with A at that time or if fat is required to absorb the A). So I am thinking I may have low RBP due to low A - not sure if due to inability to turn beta-carotene into A or due to CBS gene now. RBP is made of A, Zn, and protein...dunno what else. So I was investigating and have this also to report:
Low ferritin causes hypothyroid. If one's thyroid TSH >=2.0 one is subclinically hypothyroid (
www.lef.org) and it causes raised cholesterol land low HCL production, and the low HCL production alone causes a need for more protein per day or else this causes an endless loop of low RBP, low ferritin, and thus low thyroid and low HCL.
But my friends just dont fall into this hole and so I think there is a Vitamin A component that is going on in my case....maybe due to CBS. Just thought I'd alert others. What precipitated this for me was that I stopped taking methylation supplements -- I did not mean to stop forever but I was so tired of being nausaous taking 42 pills...the only things I kept taking were my hormones, D,E, and C. Made me sick - of course. But it is so frustrating that no one else has to be addicted to many, many expensive and nauseating supplements as I seem to be.
Well anyway, be aware you'all may be finding retinol deficiencies.
http://books.google.com/books?hl=en&...etinol&f=false
It also makes me wonder if this can happen (oxidation/destruction of retinol) due to TRANSIENT rises in homocysteine such as after meals (making choline and betaine important to protecting retinol?).
