Tom67inMA raised this issue in the "Methyl Donor Micronutrients that Modify DNA Methylation and Cancer Outcome" thread:
"I have an MTHFR gene defect (as does about half of the US population), and my GP has recommended methylated folate and TMG supplementation to reduce my homocysteine. Does this still make sense post diagnosis?"
Studies of methyl intake & cancer risk can be confusing. That is mostly because:
- cellular hypomethylation, due to methyl deficiency, can lead to DNA instability & increased risk for cancer, whereas:
- hypermethylation, favored by some cancers, can silence protective anti-cancer genes & increase mortality risk.
One might say that in PCa, we want to have methyl sufficiency before cancer develops, & insufficiency thereafter.
Most men are unaware of their methyl status unless homocysteine is elevated, in which case adjustment of dietary B vitamins might lower levels.
For those with a major MTHFR gene defect, it's a little more complicated.
Cells receive their methyl from SAM [SAMe] & this leaves homocysteine. Homocysteine can be recycled back to SAM (via methionine) if there is dietary methyl available (primarily from folate). This requires an enzyme: Methylene tetrahydrofolate reductase (MTHFR). The gene that encodes the enzyme comes in different flavors. I tend to view common genetic variants (polymorphisms) as being natural, rather than as defects, but there can be health consequences. Anyway, the variant that concerns us is the C677T.
"About ten percent of the North American population are T-homozygous for this polymorphism." "Individuals of 677TT are predisposed to mild hyperhomocysteinemia (high blood homocysteine levels), because they have less active MTHFR available to produce 5-methyltetrahydrofolate (which is used to decrease homocysteine)." [1]
From a 2015 meta-analysis [2]:
"... the protective effect of homozygote TT against high aggressive PCa was proved to have significant difference."
It's not much to go on, but I'd be cautious in addressing elevated homocysteine due to C677T.
-Patrick