The implications of following dietary advice regarding fish consumption frequency and meal size for the benefit (EPA + DHA and Se) versus risk (MeHg) assessment.

Fish contain healthy nutrients, such as ω3 polyunsaturated fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which protect against cardiovascular disease, and selenium (Se), which reduces methylmercury (MeHg) toxicity. Fish are also a dietary source of MeHg. This requires an assessment of the benefits versus risks. A risk-benefit evaluation showed that blue shark regardless of the way it is cooked generated high probabilities of surpassing the MeHg tolerable weekly intake (TWI), >22%. In tuna, boiling and grilling led to higher MeHg risks than canning, 6-37% versus <7%. EPA + DHA contributed for the prevention of coronary disease. With exception of blue shark, Se neutralised MeHg toxicity. Higher MeHg risk was associated with blue shark and boiled and grilled tuna consumption. For tuna, however, high Se content after boiling and grilling may mitigate MeHg risk.