Fish intake and serum fatty acid profiles from freshwater fish

Although high mercury concentrations in fish diets raise an alarm, fish can also be a healthy choice because it is the primary source of n-3 fatty acids (FAs). However, little information is available on the contribution of freshwater fish to serum FA concentrations.

This study examined the FA pathway from fish to serum in 243 moderate consumers of freshwater fish.

A food-frequency questionnaire was used to determine the intakes of freshwater fish caught locally and not sold in markets and of fish purchased in markets (x +/- SD: 58 +/- 63 g/d). Locally caught freshwater fish accounted for an average of 45% of total fish intake. Fish were categorized as lean or fatty on the basis of the eicosapentaenoic acid + docosahexaenoic acid content estimated from published data. Serum FA concentrations were determined by gas chromatography.

The results showed no relation between total fish intake or estimated n-3 FA intake from all fish and serum n-3 FA concentrations. Only fatty fish intake, particularly salmonid, and estimated EPA + DHA intake from fatty fish were significantly associated with serum EPA + DHA (R2 = 0.41 and 0.40, respectively). No relation was observed between the quantity of locally caught fish (g/d) consumed or the estimated FA intake from locally caught fish and serum n-3 FAs. Age, sex, and lipid metabolism medication were associated with serum n-3 FA concentrations. Neither blood selenium nor blood mercury was associated with serum FAs.

The relation between fatty fish consumption and serum n-3 FAs cannot be generalized to all fish intakes.