Reduction of C-reactive protein with isoflavone supplement reverses endothelial dysfunction in patients with ischaemic stroke.

Randomized placebo-controlled intervention in adults with established cardiovascular disease, specifically patients with a history of ischemic stroke, recruited from medical outpatient clinics and receiving stable standard medical therapy. For the isoflavone group, 50 participants were randomized/analyzed.

The active regimen was 80 mg/day purified isoflavone extracted from soybeans, given orally in capsule form for 12 weeks. The comparison group received placebo.

Twelve weeks of isoflavone supplementation improved endothelial function and reduced inflammation in this population. Brachial flow-mediated dilation was higher with isoflavone, with a treatment effect of 1.0% (95% CI 0.1-2.0; P = 0.035), and the odds ratio for impaired FMD at 12 weeks was 0.32 (95% CI 0.13-0.80; P = 0.014). High-sensitivity C-reactive protein also decreased, with a treatment effect of -1.7 mg/L (95% CI -3.3 to -0.1; P = 0.033). Other outcomes, including NMD, blood pressure, heart rate, fasting glucose, insulin, HbA1c, and oxidative stress markers, did not differ significantly, and the capsules were well tolerated with no significant side effects.

The intervention was short term at 12 weeks and involved a modest sample size, with 50 participants in the active isoflavone arm. Generalizability is limited by the single recruitment context, lack of a specified geographic setting, and a population with relatively high background dietary isoflavone intake. Some baseline details and subgroup information were not fully reported.