title: Effect of diet on serotonergic neurotransmission in depression.
abstract: Depression is characterized by sadness, purposelessness, irritability, and impaired body functions. Depression causes severe symptoms for several weeks, and dysthymia, which may cause chronic, low-grade symptoms. Treatment of depression involves psychotherapy, medications, or phototherapy. Clinical and experimental evidence indicates that an appropriate diet can reduce symptoms of depression. The neurotransmitter, serotonin (5-HT), synthesized in the brain, plays an important role in mood alleviation, satiety, and sleep regulation. Although certain fruits and vegetables are rich in 5-HT, it is not easily accessible to the CNS due to blood brain barrier. However the serotonin precursor, tryptophan, can readily pass through the blood brain barrier. Tryptophan is converted to 5-HT by tryptophan hydroxylase and 5-HTP decarboxylase, respectively, in the presence of pyridoxal phosphate, derived from vitamin B(6). Hence diets poor in tryptophan may induce depression as this essential amino acid is not naturally abundant even in protein-rich foods. Tryptophan-rich diet is important in patients susceptible to depression such as certain females during pre and postmenstrual phase, post-traumatic stress disorder, chronic pain, cancer, epilepsy, Parkinson's disease, Alzheimer's disease, schizophrenia, and drug addiction. Carbohydrate-rich diet triggers insulin response to enhance the bioavailability of tryptophan in the CNS which is responsible for increased craving of carbohydrate diets. Although serotonin reuptake inhibitors (SSRIs) are prescribed to obese patients with depressive symptoms, these agents are incapable of precisely regulating the CNS serotonin and may cause life-threatening adverse effects in the presence of monoamine oxidase inhibitors. However, CNS serotonin synthesis can be controlled by proper intake of tryptophan-rich diet. This report highlights the clinical significance of tryptophan-rich diet and vitamin B(6) to boost serotonergic neurotransmission in depression observed in various neurodegenerative diseases. However pharmacological interventions to modulate serotonergic neurotransmission in depression, remains clinically significant. Depression may involve several other molecular mechanisms as discussed briefly in this report.
authors.affiliation: Saint James School of Medicine, Kralendijk, Bonaire, The Netherlands Antilles, Dutch Caribbean.
authors.forename: Faisal
authors.initials: F
authors.lastname: Shabbir
authors.forename: Akash
authors.initials: A
authors.lastname: Patel
authors.forename: Charles
authors.initials: C
authors.lastname: Mattison
authors.forename: Sumit
authors.initials: S
authors.lastname: Bose
authors.forename: Raathathulaksi
authors.initials: R
authors.lastname: Krishnamohan
authors.forename: Emily
authors.initials: E
authors.lastname: Sweeney
authors.forename: Sarina
authors.initials: S
authors.lastname: Sandhu
authors.forename: Wynand
authors.initials: W
authors.lastname: Nel
authors.forename: Afsha
authors.initials: A
authors.lastname: Rais
authors.forename: Ranbir
authors.initials: R
authors.lastname: Sandhu
authors.forename: Nguasaah
authors.initials: N
authors.lastname: Ngu
authors.forename: Sushil
authors.initials: S
authors.lastname: Sharma
mesh_terms: D003863:Depression / Q000378:metabolism* / Q000503:physiopathology; D004032:Diet; D004827:Epilepsy / Q000378:metabolism / Q000503:physiopathology; D006801:Humans; D010300:Parkinson Disease / Q000378:metabolism / Q000503:physiopathology; D016574:Seasonal Affective Disorder / Q000378:metabolism / Q000628:therapy; D012701:Serotonin / Q000502:physiology*; D009435:Synaptic Transmission; D025101:Vitamin B 6 / Q000502:physiology
chemical_list: D012701:Serotonin; D025101:Vitamin B 6