myelin . 58 An Australian systematic review investigated the effects of B vitamins on psychiatric disorders . 59 The results suggested that B vitamins were beneficial to reducing stress and a trend was found for depression . However , there was no effect on anxiety . 59
A deficiency of vitamin B6 has
60 , 61 been associated with depression and inflammation . 62 Vitamin B6 ( Pyridoxine ) is involved in neurological development 63 and the formation of haemoglobin . 63 The active form of vitamin B6 ( pyridoxal-5-phosphate ) plays an essential role in the metabolism of neurotransmitters , such as serotonin , dopamine , glutamate , and gammaaminobutyric acid ( GABA ). 62 A deficiency in folate has been associated with depression 64 and cognitive dysfunction and decline . 65 Folate is essential for normal healthy growth and development , 65 amino acid metabolism , 63 and DNA methylation , 63 , 66 among other functions . 5,10-methylene tetrahydrofolate reductase ( MTHFR ) is a key enzyme in the metabolism of folate . 67 An MTHFR polymorphism represents a potential risk factor for numerous health conditions and diseases , such as depression , 68-70 postmenopausal depression , 70 schizophrenia , 68-70 bipolar disorder , 68-70 autism spectrum , 70 attention deficit hyperactivity disorder ( ADHD ), 70 neurological symptoms , 71 cardiovascular disease , 67 , 72 , 73 and inflammation . 74 Vitamin B12 is involved in normal functioning of the nervous system , 75 myelin synthesis , 75 and blood cell formation . 75 Melancholic depressive symptoms were more relatively associated with lower plasma vitamin B12 levels . 20 Vitamin B12 is one of the essential nutrients for monoamine neurotransmitter synthesis in the brain . 20 A deficiency in vitamin 12 has been associated with dysfunction of the central and peripheral nervous systems , 75 and neuropathy , 75 and with an increased risk of depression 75 and fatigue . 75
Vitamin D Vitamin D has antioxidant , antiinflammatory , pro-neurogenic , and
Vitamin D supplementation has been shown to promote an increase in serum serotonin in individuals suffering from depression .
neuromodulatory properties that appear to be fundamental to its antidepressant and anxiolytic functions . 48 Vitamin D is capable of crossing the blood – brain barrier . 19 There is an increased region-specific expression of vitamin D receptors ( VDRs ) in brain areas ( such as prefrontal and cingulate cortices ) known to play a key role in mood regulation . 19 Neurons and glial cells express vitamin D receptors and vitamin D-metabolising enzymes in various regions , such as the prefrontal cortex and hippocampus , suggesting a possible role for vitamin D in depression and anxiety disorders . 48 Research is suggesting that the neuroprotective properties of vitamin D are via its anti-inflammatory effects . 19 Vitamin D supplementation has been shown to promote an increase in serum serotonin in individuals suffering from depression . 48
Vitamin D insufficiency is estimated to affect about 50 % of the global population . 76 There is an inverse association between serum vitamin D levels and symptoms of depression and anxiety . 48 A deficiency of vitamin D has been associated with an increased risk of developing depression and anxiety . 48 Cross-sectional studies and cohort studies have found that people with depression had lower levels of vitamin D than controls , and that those with the lowest vitamin D levels had the greatest risk of depression . 19
Additionally , research has found a relationship between low serum vitamin D concentration during pregnancy and elevated postpartum as well as antepartum depression . 19
Omega-3 An inverse relationship has been observed for omega-3 intake and depression . 39 Epidemiological studies have consistently associated poor omega-3 status with depression and anxiety . 77 Omega-3 has antiinflammatory properties , and is involved in cell membrane composition and function , cell signalling , endothelium
52 , 78-80 function , and platelet function .
Magnesium A deficiency of magnesium has been associated with depression , 81 , 82 fatigue , 82 anxiety , 63 , 81 , 82 apathy , 81 , 82 81 , 82
agitation , irritability , 82 nervousness , 82 , 83 and muscle spasms . 63 , 81 , 83 Magnesium is involved in over 300 enzyme reactions . 63 , 82 , 84-86 Magnesium plays a
82 , 85 , 86 major role in energy metabolism , mitochondrial health , 83 muscle relaxation , 82 83 , 84 , 86
nerve function , neurotransmission , 82 , 83 , 85 , 86 and neurotransmitters . 83 The antidepressant action of magnesium is mediated by several mechanisms . The most important mechanism seems to be involving the inhibition of the glutamatergic N-methyl-D-aspartate receptor ( NMDAR ). 87 An interesting note is
192 | vol29 | no4 | JATMS