Neuropsychiatric symptoms, omega-3, and mercury exposure in freshwater fish-eaters

Mercury is a neurotoxin, absorbed primarily through fish consumption. However, the nutritional benefit from omega-3 fatty acids (n-3 FA) may offset the deleterious effects of mercury. Increased n-3 FA have been associated with lower rates of mood disorders. The authors examined neuropsychiatric symptoms among 243 freshwater fish-eaters, with low serum n-3 FA (median = 0.11 mg/mL) and low mercury exposure (median in blood and hair = 2.22 and 0.54 microg/g). They assessed neuropsychiatric symptoms with the Brief Symptom Inventory. The results did not show the expected inverse association between serum n-3 FA and neuropsychiatric symptoms. For men who consumed more than 130 g of alcohol per week, the authors observed a positive association between serum n-3 FA and neuropsychiatric symptoms, possibly reflecting an alcohol-related release of n-3 FA from membranes into blood. They observed a positive relation between hair mercury and neuropsychiatric symptoms solely for women, suggesting that men may respond differently to mercury.