Folate is involved in neurotransmitter synthesis and critical enzymatic reactions throughout the body. By depleting excess homocysteine, folate benefits cardiovascular health and nervous system function.
Those who take ordinary folic acid supplements, however, may not be experiencing its full spectrum of effects. This is because folic acid is itself not biologically active, but its biological importance is due to its active form called 5-methyltetrahydrofolate (5-MTHF) after its conversion to dihydrofolic acid in the liver. Research shows that in a large proportion of the population, genetic dihydrofolate reductase enzyme deficiencies limited the conversion of folate to 5-MTHF, leaving many vulnerable to low blood 5-MTHF levels (and higher than desired homocysteine).
A more useful approach is to take the bioactive folate 5-MTHF directly, which has been declassified as a drug and is now available as a dietary supplement. 5-MTHF has been shown to dramatically raise red blood cell folate levels compared with folic acid supplementation. 5-MTHF is up to seven times more bioavailable than folic acid. This greater bioavailability is especially important in people who have a genetic enzyme deficiency since 5-MTHF requires no conversion to be biologically active.
People with elevated homocysteine levels have a greater risk of cognitive decline. Unlike folic acid, 5-MTHF is able to cross the blood-brain barrier, which is especially important for people with cognitive difficulties to enhance the synthesis of acetylcholine in the brain - the neurotransmitter associated with memory.