GLOSSARY

Demethylation removes a methyl group from a molecule.

One-carbon metabolism transfers small carbon units through folate, methionine and biosynthetic networks. It supports nucleotides and methylation rather than one stand-alone detox cycle. Folate, cobalamin and related cofactors contribute, but requirements need nutritional assessment. A gene or metabolite name does not prescribe universal high-dose vitamins or methyl donors. Distinguish normal biochemical roles, clinically relevant deficiency and claims about optimizing methylation in otherwise adequately nourished athletes.

Methylation transfers methyl groups and demethylation removes them, not always on DNA or improved by simply increasing activity. SAM is a major donor that changes after transfer; homocysteine can be remethylated or enter transsulfuration. Enzymes and cofactors regulate these links. A homocysteine value does not establish one cause, and nutrition does not aim to maximize every methylation reaction indiscriminately. Biochemical cycling and demonstrated clinical benefit from supplementation remain distinct.

Amino acids support proteins and other compounds, while carbon skeletons can enter energy pathways after nitrogen handling. There is no unlimited dedicated amino-acid store comparable to fat storage. Oxidation of some protein does not prove total intake inadequate or unlimited extra intake builds more muscle. Athletes need total amount, quality, distribution and adequate energy alongside training load. Carbon fate, nitrogen disposal and protein synthesis are separate processes rather than one simple anabolic-versus-waste label.