A study by researchers at the University of York and Hull York Medical School has confirmed a link between depression and low levels of folate.
Folate is a vitamin that comes from vegetables such as spinach and turnip greens, dried beans and peas. Fortified cereal products, sunflower seeds as well as liver are rich sources of folate.
Experts have been claiming that adding folate to bread or flour will decrease the number of babies with disabilities such as spina bifida, miscarriage, neonatal death or lifelong disability, and now the review lends support to this claim.
As a part of their study, the researchers carried out a review of 11 previous studies involving 15,315 participants.
Based on their findings they state that though they cannot prove that low folate causes depression, the results had certainly shown a link between the two.
"Our study is unique in that for the first time all the relevant evidence in this controversial area has been brought together. Although the research does not prove that low folate causes depression, we can now be sure that the two are linked," said Dr Simon Gilbody, the lead researcher.
"Interestingly, there is also some trial evidence that suggests folic acid supplements can benefit people with depression. We recommend that large trials should be carried out to further test this suggestion," he added.
Folate is linked to the production of some of the 'feel good' chemicals in the brain, such as serotonin. The identification of this gene provides a plausible explanation as to why folic acid supplements may help people with depression.
The study is published in the July edition of the Journal of Epidemiology and Community Health.