Fish intake and serum fatty acid profiles from freshwater fish.

BACKGROUND: 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.

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

DESIGN: 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.

RESULTS: 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.

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