Dietary intakes of α-linolenic and linoleic acids are inversely associated with serum C-reactive protein levels among Japanese men
Dietary intakes of α-linolenic and linoleic acids are inversely associated with serum C-reactive protein levels among Japanese men
Year: 2009
Authors: Poudel-Tandukar, K. Nanri, A. Matsushita Y. Sasaki, S. Ohta M. Sato, M. Mizoue, T.
Publication Name: Nutrition Research
Publication Details: Volume 29; Pages 363 – 370.
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)
C-reactive protein (CRP) 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. α-linolenic acid (ALA) has an anti-inflammatory effect and favorable effects on serum CRP concentrations. In this study, the authors hypothesized that higher intakes of n- 3 PUFA, n-6 PUFA, and the different fatty acids of these families are each associated with lower levels of inflammation. This is based in part on the observation that in Japan where CVD and inflammatory conditions are at low levels, the average diet is high in both n-3 PUFA and n-6 PUFA. This investigation was conducted in a Japanese population and examined the association between PUFA intake and serum CRP concentrations. An inverse relationship between dietary intake of not only n-3 PUFA but also n-6 PUFA and serum CRP concentrations in a population of Japanese subjects was found. The relationship of serum CRP concentrations to the dietary intake of n-3 or n-6 PUFA, ALA, and LA reached statistical significance in men only. Although not statistically significant, serum CRP concentrations tended to decrease with increasing intakes of n-3 PUFA, EPA, and DHA in women. High dietary intake of ALA was inversely associated with low serum CRP concentrations. Contrary to the customary assumption that a high intake of LA induces inflammation, a significant inverse association between LA intake and serum CRP concentrations in men was found. The benefits of increased consumption of n-3 PUFA on inflammation have been attributed to their inhibitory effect on the production of inflammatory mediators via an increase in plasma, cell and tissue long chain n-3 PUFA. The present results suggest that not only does n-3 PUFA but also n-6 PUFA play an important role in lowering systemic inflammation. (Editors comments)
C-reactive protein (CRP) 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. α-linolenic acid (ALA) has an anti-inflammatory effect and favorable effects on serum CRP concentrations. In this study, the authors hypothesized that higher intakes of n- 3 PUFA, n-6 PUFA, and the different fatty acids of these families are each associated with lower levels of inflammation. This is based in part on the observation that in Japan where CVD and inflammatory conditions are at low levels, the average diet is high in both n-3 PUFA and n-6 PUFA. This investigation was conducted in a Japanese population and examined the association between PUFA intake and serum CRP concentrations. An inverse relationship between dietary intake of not only n-3 PUFA but also n-6 PUFA and serum CRP concentrations in a population of Japanese subjects was found. The relationship of serum CRP concentrations to the dietary intake of n-3 or n-6 PUFA, ALA, and LA reached statistical significance in men only. Although not statistically significant, serum CRP concentrations tended to decrease with increasing intakes of n-3 PUFA, EPA, and DHA in women. High dietary intake of ALA was inversely associated with low serum CRP concentrations. Contrary to the customary assumption that a high intake of LA induces inflammation, a significant inverse association between LA intake and serum CRP concentrations in men was found. The benefits of increased consumption of n-3 PUFA on inflammation have been attributed to their inhibitory effect on the production of inflammatory mediators via an increase in plasma, cell and tissue long chain n-3 PUFA. The present results suggest that not only does n-3 PUFA but also n-6 PUFA play an important role in lowering systemic inflammation. (Editors comments)
