Diet rich in fish could keep depression at bay, claim researchers
A diet rich in fish may help lower the risk of developing depression, conclude researchers from China's Qingdao University.
The findings, published in the Journal of Epidemiology & Community Health, involved an analysis of pooled data that appears to suggest a link between a diet rich in fish and a lowered risk of developing mental health problems.
The benefits of eating fish for the brain have long been suspected, with fish dubbed 'brain food' by parents trying to persuade their children to eat the often strong-smelling dish, but this is the first time, claim the researchers, that such a clear association has been made. Numerous studies have previously attempted to identify the role of certain foods in relation to depression risk but their findings were often inconsistent and inconclusive.
The combined data, collected between 2001 and 2014, studied 150,278 participants from Europe, North America, Asia, Oceania and South America. Ten of the 26 studies involved the monitoring of individuals who had no history of depression while the remainder were cross-sectional and looked at associations between the condition and other variables.
After pooling all the data together, researchers say a 'significant association' emerged between those who frequently ate fish - with the highest decrease in risk noted among Europeans. Overall, high fish consumption was found to lower the risk of developing depression among men by 20% and by 16% in women.
Professor Dongfeng Zhang, from the Medical College of Qingdao University, who led the study, says: "Higher fish consumption may be beneficial in the primary prevention of depression." However, he adds: "Future studies are needed to further investigate whether this association varies according to the type of fish."
The research team note that, as an observational study, no definitive conclusions can be drawn regarding cause and effect, however there may be what the they describe as a "plausible biological explanation" for the findings.
According to the World Health Organization, depression affects an estimated 350 million people of all ages worldwide, and is predicted to become the second leading cause of ill health by 2020. Currently, women are more likely to suffer from depression than men but physiological causes for the condition remain poorly understood.
Characterised by persistent feelings of sadness, a lack of enthusiasm, an inability to enjoy usually pleasurable experiences and detachment from others, serious depression can blight lives and, if unrelenting and prolonged, can even lead to suicide.
While some depressive episodes may be circumstantial - triggered by situations and events outside of an individual's control, such as health problems, relationship breakdown or bereavement - clinical depression often has no definitive cause and can be more complex and prolonged. A range of treatments including medication and cognitive behavioural therapy or 'talking therapy' may be required.
Omega 3 and tryptophan
It has been suggested that Omega 3 fatty acids, found in high quantities in some fish such as salmon, tuna and mackerel, may affect the microstructure of brain membranes. It is claimed that they may help to modify the action of the neurotransmitters dopamine and serotonin, the so-called "happy chemicals", a shortage of which are both thought to be involved in depression.
Fish, including salmon, tuna and prawns also contains high levels of the amino acid tryptophan, low levels of which have been found in those with depression. Tryptophan, converted into serotonin by the body, can only be sourced via the diet.
In addition, fish offers a source of high quality protein, vitamins and minerals and regular consumption should accompany a healthy, balanced diet that includes fruit and vegetables - a healthy diet and regular exercise is considered by experts to be a crucial factor in fighting depression.
Rachel Boyd, information manager at mental health charity Mind, says their guide, Food and Mood, includes information and advice on eating the "good fats" including those found in fish. She adds: "It is important not to oversimplify the results as there are lots of different factors in the development of depression."
"But we really agree that having these fatty acids in your diet can be helpful, and it's something where people can make quite small changes that could have quite a big impact."
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