Conclusions Whole flaxseed , but not flaxseed oil and lignan extract , has significant effects on improving glycemic control .
Context The results of human clinical trials investigating the effects of flaxseed on glucose control and insulin sensitivity are inconsistent .
Objective The present study aim ed to systematic ally review and analyze r and omized controlled trials assessing the effects of flaxseed consumption on glycemic control .
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 aim ed to investigate the effect of a flaxseed-derived lignan supplement on glycemic control , lipid profiles and insulin sensitivity in type 2 diabetic patients . Methodology /Principal Findings This was a r and omized , 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 r and omized 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 HbA1c ( -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 µg/mL , P<0.001 ) . Data also suggested minimal competition between lignan and isoflavones for bioavailability when measured by the excretion concentrations . Conclusions / Significance Daily lignan supplementation result ed 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 vali date these findings and explore the efficacy of lignans on type 2 diabetes . Trial Registration Clinical Trials.gov
Conclusions Whole flaxseed , but not flaxseed oil and lignan extract , has significant effects on improving glycemic control .
Context The results of human clinical trials investigating the effects of flaxseed on glucose control and insulin sensitivity are inconsistent .
Objective The present study aim ed to systematic ally review and analyze r and omized controlled trials assessing the effects of flaxseed consumption on glycemic control .