Beware of methylmercury during pregnancy!
Dr. Henry A. Nasrallah is correct that wild salmon is a good choice for pregnant women who want to boost intake of omega-3 fatty acids (Current Psychiatry, Comments & Controversies, December 2014; pg 33 [https://bit.ly/1wQoXdP]). The main concern about fish intake during pregnancy is exposure to methylmercury, and much of this concern is derived from the tragic results of epic mercury poisonings of food sources in the past.
The FDA advises that pregnant women and children avoid eating shark, tilefish, king mackerel, and swordfish because these fish have a relatively high level of mercury.1 Fish that are low in methyl-mercury include salmon and canned light tuna. (More information is available at https://www.fda.gov/Food/ResourcesForYou/HealthEducators/ucm083324.htm.)
Although wild fish tend to be higher in omega-3 fatty acids than farm-raised fish, farmed fish can be an excellent source of omega-3 fatty acids. This is analogous to eating farm-produced livestock vs free-range, grass-fed livestock: Animals in their natural environment eat healthier and have more omega-3 fatty acids, whereas farmed livestock generally eat cheap and less healthy feed. Because wild fish can be pricey, it’s important that women understand that farm-raised fish are a good source of protein and other nutrients such as omega-3 fatty acids.
Research has been inconclusive regarding the antidepressant benefits of omega-3 fatty acids, with some, but not all, studies demonstrating an add-on benefit of omega-3 fatty acid supplements for mood disorders. However, several epidemiological studies have reported that the low quality of dietary intake of omega-3 fatty acids is associated with psychiatric illness, and fish and seafood are sources of essential fatty acids and other nutrients.2
