Association of dietary amino acids with low mood.

Diet may affect mood and cognitive functions. Tryptophan and serine augmentation strategies have been applied for patients with mood or psychotic disorders. We studied the association between dietary intake of amino acids and low mood. We studied 29,133 men aged 50-69 years for 5-8 years in a population-based trial in Finland. Intake of amino acids was calculated from a diet history questionnaire completed by 27,111 men at baseline. Self-reports of depressed mood were recorded thrice a year, data on hospital treatment due to depressive disorders were derived from the national Hospital Discharge Register, and suicides were identified from death certificates. Participants were smokers at study entry. Strengths of our study include detailed data on food consumption, a substantial number of study participants, a long prospective follow-up time, and versatile data on indices of low mood. We found no association between the dietary intake of amino acids and self-report of depressed mood or risk of suicide. However, dietary intake of lysine and serine was associated with risk of hospital treatment due to major depressive disorder but these associations disappeared after excluding from analysis those who had reported depressed mood at study entry. There is no consistent association between dietary intake of amino acids and low mood.