overmethylation

Overmethylation is a term used in biochemistry and, in some medical and alternative medicine contexts, to describe a state in which methyl group transfer reactions are heightened, leading to increased methylation of biomolecules such as DNA, proteins, and neurotransmitters. It is not a single formal medical diagnosis.

Methyl groups are donated primarily by S-adenosylmethionine (SAMe) in the methionine cycle; the balance with S-adenosylhomocysteine (SAH) regulates methyltransferase activity. Elevated SAM or a high SAM/SAH ratio can raise methylation activity; genetic variants such as MTHFR, dietary excess of methyl donors (folate, B12, choline, methionine), liver or kidney dysfunction, and certain medications can influence this balance. DNA methylation and histone methylation are key epigenetic mechanisms.

In epigenetics, hypermethylation of promoter regions can silence gene expression (for example, tumor suppressor genes in cancer). In clinical or alternative medicine discussions, "overmethylation" is sometimes used to describe neurotransmitter imbalances attributed to excess methylation affecting serotonin, dopamine, or histamine pathways, though this usage is not standardized.

Reported associations in nonstandard practice include mood changes and anxiety or sensitivity to methyl donors; mainstream medicine treats such links cautiously due to limited evidence and lack of clear diagnostic criteria.

Assessment may involve measuring homocysteine, folate, and B12 levels, or analyzing SAM/SAH ratios and DNA methylation patterns. Treatment depends on the underlying cause and may include balanced methyl donor intake, correcting nutritional deficiencies, or, in cancer, the use of DNA methyltransferase inhibitors; there is no general, widely accepted therapy labeled "overmethylation."

Related topics include epigenetics, DNA methylation, SAMe, folate, and the methionine cycle.