Folate, Vitamin B12, and Neuropsychiatric Disorders

Abstract

Folate and vitamin B,, are required both in the methylation of homocysteine to methionine and in the synthesis of S-adenosylmethionine. S-adenosylmethionine is involved in numerous methylation reactions involving proteins, phospholipids, DNA, and neurotransmitter metabolism. Both folate and vitamin B,, deficiency may cause similar neurologic and psychiatric disturbances including depression, dementia, and a demyelinating myelopathy. A current theory proposes that a defect in methylation processes is central to the biochemical basis of the neuropsychiatry of these vitamin deficiencies. Folate deficiency may specifically affect central monoamine metabolism and aggravate depressive disorders. In addition, the neurotoxic effects of homocysteine may also play a role in the neurologic and psychiatric disturbances that are associated with folate and vitamin B,, deficiency.

Adherence to the Mediterranean diet and quality of life in the SUN Project

“…On the other hand, B-vitamins and folate are involved in serotonin and other monoamine neurotransmitters synthesis and other methylation reactions, for example, homocysteine catabolism (Bottiglieri, 1996). Another factor that can be taken into account to explain our findings is the educational or social level.…”

A review of lifestyle factors that contribute to important pathways associated with major depression: Diet, sleep and exercise

“…Other nutrients which are altered in patients with major depression and that can influence neurotransmitter production include tryptophan (and other large neutral amino acids: valine, leucine, isoleucine, phenylalanine and tyrosine) (Maes et al, 2011c, Markus, 2008, Toker et al, 2010, folic acid (Miller, 2008, Stahl, 2008, zinc , Szewczyk et al, 2011, vitamin B12 (Bottiglieri, 1996, Deana et al, 1977), vitamin B6 (Calderon-Guzman et al, 2004, Demisch and Kaczmarczyk, 1991, Hartvig et al, 1995 and iron (Baumgartner et al, 2012, Burhans et al, 2005, Coe et al, 2009). Omega-3 EFAs are also able to modify monoaminergic neurotransmission (Chalon, 2006, Su, 2009).…”

Subjective well-being in older adults: folate and vitamin B12independently predict positive affect

“…Negative associations between folate and vitamin B 12 at baseline and homocysteine 18 months later reflect the causal relationship of folate and vitamin B 12 with levels of homocysteine (3) . Our cross-sectional analyses suggest that folate contributes more to homocysteine than vitamin B 12 , consistent with previous reports (60) .…”

“…Homocysteine is an amino acid that, at high levels, is associated with adverse health outcomes such as CVD (5) and depression (6) ; SAMe is a methyl donor with potential antidepressant properties due to its involvement in the metabolism of neurotransmitters such as norepinephrine, dopamine, melatonin and serotonin (7) . Functional deficiencies of folate or vitamin B 12 may, therefore, potentially result in disturbed mood either directly or indirectly via elevated homocysteine (3) and reduced SAMe concentrations (8) . Cross-sectional studies have found an association between depression and concentrations of folate (1,9) , vitamin B 12 (10,11) and homocysteine (12,13) .…”

“…Growing evidence suggests that B-vitamins such as folate (1) and vitamin B 12 (2) are implicated in mental health. Both folate and vitamin B 12 are necessary for the methylation of homocysteine to methionine (3) , the precursor of S-adenosylmethionine (SAMe) (4) . Homocysteine is an amino acid that, at high levels, is associated with adverse health outcomes such as CVD (5) and depression (6) ; SAMe is a methyl donor with potential antidepressant properties due to its involvement in the metabolism of neurotransmitters such as norepinephrine, dopamine, melatonin and serotonin (7) .…”