Background: Several studies have reported that the intake of n–3 polyunsaturated fatty acids (PUFAs) or fish is inversely associated with serum C-reactive protein (CRP) concentrations, but few studies have evaluated the relations between serum CRP concentrations and consumption of n–3 PUFAs derived from marine products in populations with a diet rich in marine products. Therefore, it is still unclear whether a greater consumption of n–3 PUFAs is associated with lower serum CRP concentrations.

Objective: The aim of this study was to investigate the relations between n–3 PUFA intake and serum CRP concentration in the Japanese, who have a diet rich in marine products.

Design: We designed a cross-sectional survey of 401 men and 570 women aged 70 y who were living in Japan. CRP concentrations were measured, and subjects whose serum CRP concentrations were 10.0 mg/L were excluded. Dietary intake was assessed with a self-administered diet-history questionnaire.

Results: After adjustment for several predictors of inflammation, the odds ratio of high CRP (1.0 mg/L) for increasing quartiles of total n–3 PUFA and eicosapentaenoic acid + docosahexaenoic acid were 1.0, 0.72, 0.57, and 0.44 (P for trend = 0.01) and 1.0, 0.91, 0.76, and 0.54 (P for trend = 0.03), respectively.

Conclusions: Greater intake of n–3 PUFAs derived from marine products, as measured with a self-administered questionnaire, was independently related to a lower prevalence of high CRP concentrations in this older Japanese population with a diet rich in marine products. Our findings suggest that even very high intakes of n–3 PUFAs may lower serum CRP concentrations.