Back November 1999, Ginger Houston-Ludlam wrote the definitive explanation of how the SAM and cycles are supposed to work and how they often don’t work. This article was originally a post to (I think) the DS-Nutrition email list, but has been posted and reposted often on Down Syndrome email lists. Here’s a snippet of the post. The entire post, with diagrams, is here.
The folic acid cycle (also called folate cycle) and SAM cycle connect at B12. Here is where all the rubber meets the road. Any deficiency anywhere in the folic acid or SAM cycles rears it’s ugly head right here. Folic acid deficient? The homocysteine bucket fills up (you can measure high homocysteine in the blood) and everything comes to a screeching halt. B12 deficient? Both homocysteine and Methyl-THF buckets fill up and everything comes to a screeching halt. Homocysteine bucket has a hole in it? The Methyl-THF bucket fills up and everything comes to a screeching halt. MTHFR is mutated? The Methylene-THF bucket fills up and everything comes to a screeching halt. In Down Syndrome the homocysteine bucket has a hole in it because the CBS gene is triplicated so CBS steals more than its fair share of homocysteine.
[edit: date clarified]
Filed under: biocchemistry, nutrition Tagged: | DS moms, folate, homocysteine, MTHFR, nutrition, SAM
