British Journal of Nutrition

Full Papers

Dietary flaxseed lignan extract lowers plasma cholesterol and glucose concentrations in hypercholesterolaemic subjects

Wei Zhanga1, Xiaobing Wanga1, Yi Liua1, Haimei Tiana1, Brent Flickingera2, Mark W. Empiea2 and Sam Z. Suna2 c1

a1 Tumor Hospital and Institute, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China

a2 James R. Randall Research Center, Archer Daniels Midland Company, 1001 Brush College Road, Decatur, Illinois 62521, USA

Abstract

Lignans, derived from flaxseed, are phyto-oestrogens being increasingly studied for their health benefits. An 8-week, randomised, double-blind, placebo-controlled study was conducted in fifty-five hypercholesterolaemic subjects, using treatments of 0 (placebo), 300 or 600 mg/d of dietary secoisolariciresinol diglucoside (SDG) from flaxseed extract to determine the effect on plasma lipids and fasting glucose levels. Significant treatment effects were achieved (P < 0·05 to < 0·001) for the decrease of total cholesterol (TC), LDL-cholesterol (LDL-C) and glucose concentrations, as well as their percentage decrease from baseline. At weeks 6 and 8 in the 600 mg SDG group, the decreases of TC and LDL-C concentrations were in the range from 22·0 to 24·38 % respectively (all P < 0·005 compared with placebo). For the 300 mg SDG group, only significant differences from baseline were observed for decreases of TC and LDL-C. A substantial effect on lowering concentrations of fasting plasma glucose was also noted in the 600 mg SDG group at weeks 6 and 8, especially in the subjects with baseline glucose concentrations ≥ 5·83 mmol/l (lowered 25·56 and 24·96 %; P = 0·015 and P = 0·012 compared with placebo, respectively). Plasma concentrations of secoisolariciresinol (SECO), enterodiol (ED) and enterolactone were all significantly raised in the groups supplemented with flaxseed lignan. The observed cholesterol-lowering values were correlated with the concentrations of plasma SECO and ED (r 0·128–0·302; P < 0·05 to < 0·001). In conclusion, dietary flaxseed lignan extract decreased plasma cholesterol and glucose concentrations in a dose-dependent manner.

(Received June 20 2007)

(Revised October 12 2007)

(Accepted December 06 2007)

(Online publication December 06 2007)

Correspondence:

c1 Corresponding author: Dr Sam Z. Sun, fax+1 217 451 7098, email sun@admworld.com

Footnotes

Abbreviations: ED, enterodiol; EL, enterolactone; HDL-C, HDL-cholesterol; LDL-C, LDL-cholesterol; SDG, secoisolariciresinol diglucoside; SECO, secoisolariciresinol; TC, total cholesterol