The effect of soy isoflavones on arterial stiffness: a systematic review and meta-analysis of randomized controlled trials

Study answer

What this study found

Soy isoflavone supplementation reduced arterial stiffness versus placebo in this meta-analysis of 8 randomized trials. Individual studies showed improvement in systemic arterial compliance in Nestel 1997 (p=0.011), augmentation index in Reverri 2015 (p=0.03), and pulse wave velocity in equol producers in Hazim 2016 (-0.2 ± 0.2 m/s vs 0.6 ± 0.2 m/s; p<0.01). Richter 2017 found no significant treatment effect on augmentation index (p=0.59) or PWV (p=0.84). The overall effect did not differ by intervention duration or gender.

Study & population

Systematic review and meta-analysis of 8 randomized controlled trials in adults, including postmenopausal women and men.

Intervention

Included trials tested soy isoflavones in tablets, soy protein isolate, soy drink, soy nuts, or S-equol, with doses ranging from 10 mg to 118 mg aglycone equivalents daily.

Key limitation

The evidence base was small, with only 8 trials and modest individual sample sizes.

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Original abstract