Dietary intakes of α-linolenic and linoleic acids are inversely associated with serum C-reactive protein levels among Japanese men Kalpana Poudel-Tandukar a, ⁎ , Akiko Nanri a , Yumi Matsushita a , Satoshi Sasaki b , Masanori Ohta c , Masao Sato d , Tetsuya Mizoue a a Department of Epidemiology and International Health, Research Institute, International Medical Center of Japan, Tokyo 162-8655, Japan b Department of Social and Preventive Epidemiology, School of Public Health, The University of Tokyo, Tokyo, Japan c Department of Health Development, University of Occupational and Environmental Health, Kitakyushu, Japan d Department of Applied Biological Chemistry, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka, Japan Received 6 April 2009; revised 26 May 2009; accepted 28 May 2009 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, docosahexaenoic acid, 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 and linoleic acid showed clear inverse relationships (P for trend = .001 and .003, respectively) in men. The results suggest that increased intake of not only α-linolenic acid (n-3 PUFA) but also linoleic acid (n-6 PUFA) has a beneficial effect on systemic inflammation in men. © 2009 Elsevier Inc. All rights reserved. Keywords: Polyunsaturated fatty acids; n-3 PUFA, n-6 PUFA, C-reactive protein; Inflammation; Cross-sectional studies; Japanese Abbreviations: AA, Arachidonic acid; ALA, α-Linolenic acid; BDHQ, Brief self-administered diet history questionnaire; BMI, Body mass index; CRP, C-reactive protein; DHA, Docosahexaenoic acid; EPA, Eicosapentaenoic acid; LA, Linoleic acid; MET-h/wk, Metabolic equivalent hours per week; PUFA, Polyunsaturated fatty acids. 1. Introduction Cardiovascular disease (CVD) is the major cause of death worldwide [1] and the second leading cause in Japan, where it accounts for 16% of total deaths [2]. Experimental and human data suggest that inflammation plays an Available online at www.sciencedirect.com Nutrition Research 29 (2009) 363 – 370 www.nrjournal.com ⁎ Corresponding author. Tel.: +81 3 3202 7181; fax: +81 3 3202 7364. E-mail address: kalpana@ri.imcj.go.jp (K. Poudel-Tandukar). 0271-5317/$ – see front matter © 2009 Elsevier Inc. All rights reserved. doi:10.1016/j.nutres.2009.05.012