Dietary long-chain n-3 fatty acids of marine origin and serum C-reactive protein concentrations are associated in a population with a diet rich in marine products

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.