Folate is essential to numerous bodily functions ranging from nucleotide biosynthesis to
the remethylation of homocysteine. The human body needs folate to synthesize DNA, repair
DNA, and methylate DNA as well as to act as a cofactor in other biological reactions.
Folate and vitamin B12 are required for the synthesis of S-adenosyl-L-methionine (SAM-e).
SAM-e is involved in numerous methylation reactions involving proteins, phospholipids,
DNA, and neurotransmitter metabolism, and is discussed in a separate chapter of this
outline. These are critical protective processes for the brain to ward off depression.
Children and adults both require folic acid in order to produce healthy red blood cells and
prevent anemia.
Folate and folic acid derive their names from the Latin word folium (which means "leaf").
Leafy vegetables are a principal source, although, in Western diets, fortified cereals and
bread may be a larger dietary source. Fortification of grains with folate has been required in
the U.S. since 1998. Lake and Spiegel caution that folate is easily inactivated by cooking and
processing.
According to Brown et al., "the most important vitamins and nutrients for mental health are
those that are essential for the functioning of nerve cells and those that are likely to be
depleted due to poor nutrition, malabsorption, rapid utilization, or deterioration due to
illness or environmental stress.”^1 Folate is a prime example.
Brown et al. caution that folate levels may be affected by chronic disease, diabetes, cancer,
smoking, alcohol use, poor diet, and medications such as mood stabilizers, L-dopa, statins,
oral anti-diabetic drugs, and cancer chemotherapy.
Several older studies found that up to 35% of depressed patients are folate deficient. In
older people, the incidence of deficiency was even more marked and might still be as high
