Depression: more fish, less risk!

High fish consumption, alone or accompanied by a diet rich in fruits, vegetables and whole grains, is associated with a 17 percent lower risk of suffering from depression, compared with low consumption. A result that sheds light on a relationship hitherto thought to be controversial. Among the mechanisms underlying the protective action of fish would be the ability of omega-3s to modify the membranes of neurons.

These are the findings arrived at by researchers from the Department of Health Epidemiology and Statistics at Qingdao University (China), conducting a study published in the Journal of Epidemiology & Community Health.

Depression: a widespread condition

Depression is a mood disorder that affects the cognitive, affective and behavioral spheres of the individual therefore unable to lead a normal life. In Italy at least 1.5 million people suffer from depression while and According to the World Health Organization, in the year 2020 depression will be the second leading cause of disease, after cardiovascular disease, worldwide.

At the origin of depression there are most likely a combination of several factors: genetic, environmental, and psychological and biological. Of the latter, particular importance seems to be the deficiency of neurotransmitters such as serotonin, norepinephrine, and dopamine. Other research has also suggested that omega-3s may also be involved in the disease. Several studies have found that individuals suffering from depression possess lower omega-3 levels than the rest of the population. In 2012, research conducted by researchers at the University of Milan on the elderly revealed that in those suffering from depression, EPA levels in red blood cell membranes were particularly low.

Nutrition and lifestyle to combat depression

The one conducted by the Chinese researchers was a meta-analysis study, i.e., research that takes into account the results of other studies, in which 26 publications on the topic were selected, conducted worldwide between 2011 and 2014, involving a total of 150. 278 people. The data obtained from the statistical analysis showed that subjects who had consumed high amounts of fish showed a 17 percent lower risk of falling into depression, compared with those who had consumed smaller amounts. The biological mechanism behind this result has not yet been clarified, but there are several hypotheses.

These also include a general tendency in those who consume more fish to follow a lifestyle that tends to be healthy not only from a dietary point of view. In addition, the omega-3 contained in fish may modify the structure of neuron membranes by facilitating the release of the neurotransmitters dopamine and serotonin. In support of this hypothesis, a meta-analysis conducted by researchers at the University of Catania was published in 2014 in the journal PloS One. In this case, scientists found that omega-3 supplementation in patients with major depressive disorder or depressive symptoms had a beneficial clinical effect compared with placebo treatment. Specifically, clinical efficacy was demonstrated in the case of omega-3 administered together with conventional therapies, highlighting their effectiveness as an adjuvant.

Fish omega-3s influence the risk of depression

According to the authors of the Chinese study, the results of the study indicate that consuming copious amounts of fish may reduce the risk of depression. Regarding this evidence, Majid Fotuhi, medical director of the Neuro Grow Brain Fitness Center in Virginia and a consultant at Johns Hopkins University (U.S.), recalled the role of omega-3s in improving blood flow, including to the brain, and counteracting mood disorders. 

Sources:Li F, Liu X, Zhang D Fish consumption and risk of depression: a meta-analysis.- J Epidemiol Community Health. 2015 Sep 10. pii: jech-2015-206278. doi: 10.1136/jech-2015-206278. [Epub ahead of print]. Giuseppe Grosso, Andrzej Pajak, Stefano Marventano, Sabrina Castellano, Fabio Galvano, Claudio Bucolo,Filippo Drago, and Filippo Caraci. "Role of Omega-3 Fatty Acids in the Treatment of Depressive Disorders: A Comprehensive Meta-Analysis of Randomized Clinical Trials." PLoS One. 2014; 9(5): e96905.Published online 2014 May 7. doi: 10.1371/journal.pone.0096905