Effects of isoflavone-rich red clover extract on blood glucose level: A randomized, double-blind, placebo-controlled trial

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#adult #blood-glucose #double-blind-method #fasting #female

Effects of isoflavone-rich red clover extract on blood glucose level: A randomized, double-blind, placebo-controlled trial

Masuda et al., 2021 | J Food Sci | Rct

Citation

Masuda Takamasa, Ino Yoshinaka, ... Osawa Toshihiko. Effects of isoflavone-rich red clover extract on blood glucose level: A randomized, double-blind, placebo-controlled trial. J Food Sci. 2021-Apr;86(4):1393-1399. doi:10.1111/1750-3841.15672

Abstract

High blood glucose is associated with increased risk of various diseases. Red clover (RC; Trifolium pratense L.) is an edible legume whose sprout is rich in isoflavones such as formononetin and biochanin A. We examined the effects of RC extract on postprandial and fasting blood glucose level, using a randomized, double-blind, placebo-controlled trial with 36 participants, aged 25 to 64 years, who were randomly assigned to receive either 1.91 g of RC extract (containing 8 mg formononetin and 1.8 mg biochanin A) or placebo. Each participant ingested the assigned test food daily for 8 weeks, and at the oral maltose tolerance test (OMTT). Initially, the two groups did not significantly differ in OMTT results. However, fasting insulin levels at 8 weeks were significantly lower in the RC group (4.76 μIU/ml at Week 0 to 4.01 μIU/ml at Week 8) with a significant interaction (P = 0.046). Subgroup analysis showed that change in blood glucose level (blood glucose ΔC) tended to decrease late in the trial period during OMTT in the ≤50-year-old RC group, as did fasting blood glucose and insulin levels at 8 weeks; hemoglobin A1c was also significantly reduced in this subgroup (5.36% at Week 0 to 5.28% at Week 8) with a significant interaction (P = 0.040). These results suggest that the daily intake of RC could reduce blood glucose, particularly for those ≤50 years old. Formononetin-an α-glucosidase inhibitor-is considered to be the major functional molecule for these effects. Therefore, intake of RC that contains formononetin might help blood glucose control.

Key Findings

Therefore, intake of RC that contains formononetin might help blood glucose control.

Outcomes Measured

  • Requires manual extraction

Population

Field Value
Population See abstract
Sample Size 36
Age Range 25 to 64 years
Condition See abstract

MeSH Terms

  • Adult
  • Blood Glucose
  • Double-Blind Method
  • Fasting
  • Female
  • Glucose Intolerance
  • Humans
  • Isoflavones
  • Male
  • Middle Aged
  • Plant Extracts
  • Trifolium

Evidence Classification

  • Level: Rct
  • Publication Types: Journal Article, Randomized Controlled Trial
  • Vertical: red-clover-menopause

Provenance

Source extracted via PubMed E-utilities API on 2026-04-09