Low mood and depression can be signs of vitamin B12 deficiency, research suggests.
Deficiency in the B vitamin has also been linked to problems with concentration and memory.
Typical symptoms of depression include decreased pleasure and energy loss.
In the long-term, supplementation with vitamin B12 may help reduce depressive symptoms, a review of the research finds.
Both vitamin B12 and folate are vital to the production of critical neurotransmitters, such as serotonin and noradrenaline.
Depression is often linked to low levels of serotonin in the brain.
Good sources of vitamin B12 include fish, poultry, eggs and low-fat milk.
Fortified breakfast cereals also contain vitamin B12.
People who may have difficulty getting enough vitamin B12 include vegetarians, older people and those with some digestive disorders, such as Crohn’s disease.
The conclusions come from a review of 11 separate studies on the link between vitamin B12 and folates on depressive symptoms.
While there were only a relatively small number of trials, some were positive, the study’s authors write:
“One trial found that the prolonged use of folic acid, vitamin B12, and vitamin B6 increased response to antidepressant treatment over one year, and decreased the risk of relapse of
symptoms amongst those who had recovered after three months.”
Overall, vitamin supplements over the long-term could be beneficial, the study’s authors conclude:
“Taken together, the results of these meta-analyses suggest that the short-term use of vitamins (days to a few weeks) does
not contribute to improve depressive symptoms, but more prolonged consumption (several weeks to years) may reduce the severity and the onset of clinically significant symptoms of depression in special populations.”
Around one-in-eight people over 50 are low in vitamin B12, recent research finds.
The study was published in the journal International Psychogeriatrics (Almeida et al., 2015).