One-carbon donation, also called methyl donation, may be at the root of many biochemical disturbances… and may be improved by providing the cofactors, such as folate, necessary for its optimal metabolism.
Folate is a B-vitamin that, as per the definition of a vitamin, cannot be synthesized de novo; it must be derived from diet or supplementation. Dietary folate is found in leafy green vegetables, legumes, beans, liver, citrus fruits, and yeast.
Folic acid is the term for the synthetic molecule…
[G]enetic polymorphisms of the methylenetetrahydrofolate reductase (MTHFR) enzyme (present in approximately 60 percent of the U.S. population)… can make it difficult to convert folate, whether dietary or supplemental, to the active form.
Folate is an essential nutrient involved – via its donation of a methyl group – in numerous biochemical pathways, including neurotransmitter synthesis, DNA biosynthesis, regulation of gene expression, amino acid synthesis and metabolism, and myelin synthesis and repair.
The thermolabile variant (C677T) of the MTHFR enzyme, which results in decreased activity…has been positively linked to low serum folate levels.
A number of studies have examined whether this common polymorphism, present in up to 60 percent of the U.S. population, might be associated with increased risk of depression.
A meta-analysis of MTHFR polymorphisms and psychiatric disorders found a 36-percent greater chance of having depression in individuals who were homozygous for the (TT) enzyme variant com- pared to wild-type variants (CC).
Folate deficiency is found in approximately one-third of depressed individuals. From the research it appears a folate level in the normal range might still be inadequate for the purpose of methyl donation and neurotransmitter synthesis. Therefore, the number of depressed people who have an insufficient amount of folate might be significantly greater.