B Vitamins May Not Cut Heart Risk

[ofonorow]

http://news.aol.com/health/story/ar/_a/ ... 1200077086
B Vitamins May Not Cut Heart Risk

I know this is part of the anti-vitamin propaganda campaign, and it might even be true, who knows.

[rizwanuk]

I feel that Folic Acid, Vitamin B6 and 12 all lower homocysteine through different means and these differences should be clearly understood. It may be that lowering homocysteine through ANY means does not work but through SOME means may work.

Vitamin B12 and Folic acid convert homocysteine back to Methionine whereas B6 further metabolizes it. Which approach is the best we dont know.

So for e.g we know that methionine reduction extends lifespan in rodents could it be that excess of Folic acid and Vitamin B12 negate/cancel the benefits of homocysteine lowering by converting it back to Methionine:

1: Exp Gerontol. 2003 Jan-Feb;38(1-2):47-52. Links
Nutritional control of aging.Zimmerman JA, Malloy V, Krajcik R, Orentreich N.
Orentreich Foundation for the Advancement of Science Inc., Cold Spring-on-Hudson, NY, USA. zimmermj@stjohns.edu

For more than 60 years the only dietary manipulation known to retard aging was caloric restriction, in which a variety of species respond to a reduction in energy intake by demonstrating extended median and maximum life span. More recently, two alternative dietary manipulations have been reported to also extend survival in rodents. Reducing the tryptophan content of the diet extends maximum life span, while lowering the content of sulfhydryl-containing amino acids in the diet by removing cysteine and restricting the concentration of methionine has been shown to extend all parameters of survival, and to maintain blood levels of the important anti-oxidant glutathione. To control for the possible reduction in energy intake in methionine-restricted rats, animals were offered the control diet in the quantity consumed by rats fed the low methionine diet. Such pair-fed animals experienced life span extension, indicating that methionine restriction-related life span extension is not a consequence of reduced energy intake. By feeding the methionine restricted diet to a variety of rat strains we determined that lowered methionine in the diet prolonged life in strains that have differing pathological profiles in aging, indicating that this intervention acts by altering the rate of aging, not by correcting some single defect in a single strain.

PMID: 12543260 [PubMed - indexed for MEDLINE]