Dietary intakes of α-linolenic and linoleic acids are inversely associated with serum C-reactive protein levels among Japanese men.

Key Findings:

ALA has been shown to have positive effects on serum C-reactive protein (CRP), which is a major acute phase reactant secreted by the liver in response to increased levels of inflammatory cytokines and is a sensitive marker for low-grade systemic inflammation. In this study, an inverse relationship between dietary intake of both n-3 PUFA and n-6 PUFA and serum CRP concentrations in a population of Japanese subjects (men only) was found. CRP tended to decrease with increasing intakes of ALA, EPA, and DHA in women. High dietary intake of ALA was inversely associated with low serum CRP concentrations attributed to an inhibitory effect on the production of inflammatory mediators via an increase in plasma, cell and tissue long chain n-3 PUFA.

ABSTRACT:

Investigations suggest a protective role of n-3 polyunsaturated fatty acids (PUFA) but opposing roles of n-6 PUFA in inflammation, but the effects in vivo the human are not clear. We therefore tested the hypothesis that higher intakes of n-3 PUFA and n-6 PUFA are associated with lower levels of inflammation among a population consuming a diet high in PUFA. This study aimed to assess the association between PUFA intake and serum C-reactive protein (CRP) concentrations in a group of Japanese employees. The study subjects were 300 men and 211 women aged 21 to 67 years working in 2 municipal offices of Japan. We measured the serum high-sensitivity CRP concentrations by the latex agglutination nephelometry method and assessed dietary habits by a validated self-administered diet history questionnaire. We analyzed the data using multiple linear regression analysis with adjustment for potential confounding variables. Mean serum CRP concentrations tended to decrease as the intake of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), or their combination increased in men and women, although none of these relationships was statistically significant. In men, there were statistically significant inverse relationships between dietary intake of n-3 or n-6 PUFA and serum CRP concentrations (P for trend = .03 and .008, respectively). Among specific PUFA, only α-linolenic acid (ALA) and linoleic acid (LA) showed clear inverse relationships (P for trend = .001 and .003, respectively) in men. The results suggest that increased intake of not only ALA but also LA has a beneficial effect on systemic inflammation in men. (Authors abstract)