In an exclusive interview with TODAY, Dr Richardson pointed out that studies have shown that rates of depression, including post-natal depression, are higher in countries with low fish and seafood intake. On the contrary, those who ate more fish and seafood had a lower risk of depression.
In a large 2009 United Kingdom study involving 15,000 women, researchers observed that mothers who ate fish rich in Omega-3 regularly, compared to those who ate very little during their pregnancy, appeared to be more protected against depression. The study was published in online medical journal PubMed.
Your mood is what you eat
"The type of diet we have not only affects our physical health. It can also impact our brains and behaviour. Fish and seafood are critical in our diets because they play an important role in brain function, yet many people don't consume enough of it now," said Dr Richardson, who is also the founder director of Food and Behaviour Research.
Fish rich in Omega-3 include the coldwater varieties such as sardines, mackerel, salmon and canned white tuna. Fish oil supplements and certain shellfish, including mussels and oysters, also contain Omega-3s.
Long-chain Omega-3s - specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) - are known for their anti-inflammatory effects, said Dr Richardson.
"Depression is known to be associated with inflammatory changes. Inflammation in the body can set off certain immune signalling molecules called cytokines, which are known to trigger depressive symptoms," she explained.
Dr Richardson added that low levels of DHA may also mess up brain signalling systems, including serotonin. In layman's terms, serotonin is also known as the happy hormone and an imbalance of serotonin levels in the body may affect the mood.
As a complement to standard treatment, the American Psychological Association recommended that people with mood or psychotic disorders should consume 1,000mg of Omega-3s (EPA and DHA) each day. It also recommended that all adults should eat fish at least twice a week.
