Correlation Between Fish Consumption and Major Depression

In this classic article to the Lancet, JR Hibbeln demonstrated that there was an inverse correlation between annual fish consumption in a country, and that country’s incidence of depression (Hibbeln, 1998.)  As you can see from the graph, those countries that consumed the most fish per capita, such as Japan, had the lowest rates of depression.  Vice versa, those countries where people consumed the lowest amount of fish, such as the United States, had the highest rates of depression per capita.  Of course, correlation is not causation – the fact that two things are linked does not mean one causes the other.  For that reason, epidemiological studies such as this one must be confirmed by other methodologies: mechanistic studies in cell cultures, animal models of illness, and randomized clinical trials.  Research on why fish consumption might help prevent depression has focused on omega-3 fatty acids.  Cellular studies have confirmed that Omega-3 fatty acids, found mostly in certain kinds of fish, but also in walnuts, soybeans, flaxseed, and some other plants, are integral components of the cell membrane of brain cells.  Without adequate omega-3’s, membrane dysfunction may lead to cellular dysfunction, and from cellular dysfunction to conditions such as depression.

Next week: what randomized clinical trials show about omega-3 consumption and depression!