Increased intake of vitamin B6 and vitamin B12 may reduce the risk of elderly people developing depression, says a new US study.
Dietary intakes of vitamins B6, B9 (folate) and B12 were estimated using food frequency records in community-based surveys of 3,503 adults 65 years and older participating in the Chicago Health and Aging project (1). Over an average of seven years of follow-up, the researchers noted that increased intakes of vitamins B6 and B12 but not folate were associated with a decreased likelihood of incident depression. The benefits did appear to be limited to supplement intakes, since no link between depressive symptoms and food intakes of B6 or B12 were observed. For every 10 milligram increase in the intake of vitamin B6 and for every 10 microgram increase in vitamin B12, the risk of developing symptoms of depression decreased by two percent per year.
How the B vitamins may influence depressive symptoms remains unknown. According to earlier studies, vitamin B12 seems to be involved in the synthesis of neurotransmitters. Vitamin B12 may also inhibit the accumulation of the amino acid homocysteine, which may lead to toxic reactions that enhance depression: middle-aged men with the highest serum concentrations of homocysteine – a reflection of poor vitamin B6, B9 and B12 status – showed a two-fold higher risk of being depressed than those with the lowest homocysteine concentrations. More research is required to explore the potential link between B vitamins and depressive symptoms.