British Journal of Nutrition

Short Communication

Effects of a flaxseed-derived lignan supplement on C-reactive protein, IL-6 and retinol-binding protein 4 in type 2 diabetic patients

An Pana1, Wendy Demark-Wahnefrieda2, Xingwang Yea1, Zhijie Yua1, Huaixing Lia1, Qibin Qia1, Jianqin Suna3, Yanqiu Chena3, Xiafei Chena3, Yong Liua1 and Xu Lina1 c1

a1 Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences and Graduate School of the Chinese Academy of Sciences, 294 Tai-Yuan Road, Shanghai 200031, China

a2 Department of Behavioral Science, The University of Texas-MD Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX 77030, USA

a3 Huadong Hospital, Fudan University, 221 West Yan-An Road, 200040, Shanghai, China

Abstract

Elevated C-reactive protein (CRP), IL-6 and retinol-binding protein 4 (RBP4) levels are associated with insulin resistance and diabetes mellitus. Phytoestrogens (including lignans and isoflavones) may enhance the management of diabetes and are hypothesized to act through inflammation pathways. The present study explored the effects of flaxseed-derived lignan on inflammatory factors and RBP4 concentrations in type 2 diabetics, who have higher levels of these biomarkers. Seventy community-dwelling diabetic patients (twenty-six men and forty-four post-menopausal women) with mild hypercholesterolaemia completed a randomized, double-blind, placebo-controlled, cross-over trial of supplementation with flaxseed-derived lignan capsules (360 mg/d) or placebo for 12 weeks, separated by an 8-week wash-out period. The participants maintained their habitual diets and levels of physical activity. Baseline to follow-up concentrations of CRP increased significantly within the placebo group (1·42 (sem 0·19) v. 1·96 (sem 0·22) mg/l, P < 0·001), but were comparatively unchanged in the lignan-supplemented group (1·67 (sem 0·19) v. 1·90 (sem 0·26) mg/l, P = 0·94); a significant difference was observed between treatments ( − 0·45 (95 % CI − 0·76, − 0·08) mg/l, P = 0·021). This effect was confined to women (P = 0·016), but not observed in men (P = 0·49). No between-treatment differences were found with regard to IL-6 or RBP4; though IL-6 concentrations increased significantly from baseline to follow-up in both groups (P = 0·004 and P < 0·001 following lignan and placebo treatments, respectively). The study suggests that lignan might modulate CRP levels in type 2 diabetics. These results need to be confirmed by further large clinical trials of longer duration.

(Received April 25 2008)

(Revised July 07 2008)

(Accepted July 31 2008)

(Online publication September 08 2008)

Correspondence:

c1 Corresponding author: Dr Xu Lin, fax +86 21 54920249, email xlin@sibs.ac.cn

Footnotes

Abbreviations: CRP, C-reactive protein; RBP4, retinol-binding protein 4

0Comments