Effects of dietary supplementation with isoflavones from red clover on ambulatory blood pressure and endothelial function in postmenopausal type 2 diabetes

Diabetes Obes Metab. 2003 Sep;5(5):325-32. doi: 10.1046/j.1463-1326.2003.00282.x.

Abstract

Objective: The aim of this study was to determine whether dietary supplementation with isoflavones from red clover affected ambulatory blood pressure and forearm vascular endothelial function in postmenopausal type 2 diabetic women.

Design: Sixteen postmenopausal type 2 diabetics treated with diet or oral hypoglycaemic therapy completed a randomized double-blind crossover trial of dietary supplementation with isoflavones from red clover (approximately 50 mg/day) for 4 weeks compared to placebo. Twenty-four-hour ambulatory blood pressure recordings and forearm vascular responses to acetylcholine, nitroprusside and L-nitromonomethylarginine (L-NMMA) were measured at the end of each treatment period.

Results: Mean daytime systolic and diastolic blood pressures were significantly lower during isoflavone therapy compared to placebo (-8.0 +/- 3.4 and -4.3 +/- 1.9 mmHg respectively, p < 0.05). The increase in forearm vascular resistance following L-NMMA was significantly greater during isoflavone supplementation (20.9 +/- 6.5) than placebo (3.7 +/- 2.9 arbitrary units, p < 0.05), suggesting an improvement in basal endothelial function. Plasma lipoproteins, glycated haemoglobin and forearm vascular responses to acetylcholine and nitroprusside did not differ significantly between isoflavone and placebo therapy.

Conclusion: Isoflavone supplementation from red clover may favourably influence blood pressure and endothelial function in postmenopausal type 2 diabetic women.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Blood Pressure / drug effects
  • Blood Pressure Monitoring, Ambulatory
  • Cross-Over Studies
  • Diabetes Mellitus, Type 2 / drug therapy*
  • Diabetes Mellitus, Type 2 / physiopathology
  • Double-Blind Method
  • Endothelium, Vascular / drug effects
  • Endothelium, Vascular / physiopathology
  • Female
  • Forearm / blood supply
  • Humans
  • Isoflavones / therapeutic use*
  • Middle Aged
  • Phytotherapy / methods*
  • Plant Extracts / therapeutic use*
  • Postmenopause
  • Trifolium*
  • Vascular Resistance / drug effects

Substances

  • Isoflavones
  • Plant Extracts