Effects of a flaxseed-derived lignan supplement in type 2 diabetic patients: a randomized, double-blind, cross-over trial.
BACKGROUND
Flaxseed consumption has been shown to improve blood lipids in humans and flaxseed-derived lignan has been shown to enhance glycemic control in animals. The study aimed to investigate the effect of a flaxseed-derived lignan supplement on glycemic control, lipid profiles and insulin sensitivity in type 2 diabetic patients.


RESULTS
This was a randomized, double-blind, placebo-controlled, cross-over trial and it was conducted between April and December 2006 in Shanghai, China. Seventy-three type 2 diabetic patients with mild hypercholesterolemia were enrolled into the study. Patients were randomized to supplementation with flaxseed-derived lignan capsules (360 mg lignan per day) or placebo for 12 weeks, separated by an 8-week wash-out period. HbA1c, lipid profiles, insulin resistance index and inflammatory factors were measured. Sixty-eight completed the study and were included in the analyses. The lignan supplement significantly improved glycemic control as measured by HbA(1c) (-0.10+/-0.65 % vs. 0.09+/-0.52 %, P = 0.001) compared to placebo; however, no significant changes were observed in fasting glucose and insulin concentrations, insulin resistance and blood lipid profiles. Urinary excretion of lignan metabolites (enterodiol and enterolactone) was significantly higher after the lignan supplement intervention compared to baseline (14.2+/-18.1 vs. 1.2+/-2.4 microg/mL, P<0.001). Data also suggested minimal competition between lignan and isoflavones for bioavailability when measured by the excretion concentrations.


CONCLUSIONS
Daily lignan supplementation resulted in modest, yet statistically significant improvements in glycemic control in type 2 diabetic patients without apparently affecting fasting glucose, lipid profiles and insulin sensitivity. Further studies are needed to validate these findings and explore the efficacy of lignans on type 2 diabetes.


BACKGROUND
ClinicalTrials.gov NCT00363233.
Pan
An
A
Key Laboratory of Systems Biology, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences and Graduate School of the Chinese Academy of Sciences, Shanghai, China.
Sun
Jianqin
J
Chen
Yanqiu
Y
Ye
Xingwang
X
Li
Huaixing
H
Yu
Zhijie
Z
Wang
Yanfang
Y
Gu
Wenjia
W
Zhang
Xinyi
X
Chen
Xiafei
X
Demark-Wahnefried
Wendy
W
Liu
Yong
Y
Lin
Xu
X
D000368:Aged; D018592:Cross-Over Studies; D003924:Diabetes Mellitus, Type 2 / Q000178:diet therapy*; D004311:Double-Blind Method; D005260:Female; D019597:Flax / Q000737:chemistry*; D006801:Humans; D017705:Lignans / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010919:Placebos; D016896:Treatment Outcome
D017705:Lignans; D010919:Placebos