Longer-term soy nut consumption improves vascular function and cardiometabolic risk markers in older adults: Results of a randomized, controlled cross-over trial

Background: Soy foods may contribute to the beneficial health effects of healthy plant-based diets on the risk to develop cardiovascular disease (CVD). However, their effects on vascular function have hardly been studied. Objective: To investigate longer-term effects of soy nut consumption on vascular function and car-diometabolic risk markers in healthy older men and women. Design: Twenty-three healthy participants (age: 60-70 years; BMI: 20-30 kg/m2) participated in a randomized, controlled, single-blinded cross-over trial with an intervention (67 g/day of soy nuts providing 25.5 g protein and 174 mg isoflavones) and control period (no nuts) of 16 weeks, separated by eight weeks wash-out. Adults followed the Dutch food-based dietary guidelines. Results: No serious adverse events were reported and the soy nut regime was well tolerated. Body weights remained stable during the whole study. A higher protein (3.1 energy percent [En%]) and a lower carbohydrate intake (2.0 En%) was observed during the intervention period. Total fat intake was comparable, but that of saturated (-1.3 En%), cis- monounsaturated (-1.5 En%) and cis-polyunsaturated fatty acids (+1.9 En%) differed. Serum isoflavone concentrations were higher after the intervention as compared with the control period (daidzein: 127.8 ng/mL; 95% CI: 74.3-181.3 ng/mL; p < 0.001 and genistein: 454.2 ng/mL; 95% CI: 266.6-641.8 ng/mL; p < 0.001). Brachial artery flow-mediated vasodi-lation was 1.48 percent points (pp; 95% CI: 0.08-2.89 pp; p = 0.040) higher following soy nut intake. The carotid artery reactivity response and arterial stiffness did not differ. Serum LDL-cholesterol was lower (0.17 mmol/L; 95% CI: 0.02-0.32 mmol/L; p = 0.027), while HDL-cholesterol and triacylglycerol con-centrations were comparable. Mean arterial pressure (MAP) was lower (3 mmHg; 95% CI: 0-6 mmHg; p = 0.035). Conclusions: Longer-term soy nut intake as part of a healthy diet improved endothelial function, LDL-cholesterol concentrations and MAP levels, suggesting mechanisms by which an increased soy food intake beneficially affects CVD risk in older adults. Registered under ClinicalTrials.gov Identifier no. NCT03627637. (C) 2022 The Author(s). Published by Elsevier Ltd.

Automated summary

This study investigated the longer-term effects of soy nut consumption on vascular function and cardiometabolic risk markers in healthy older adults. The results showed that long-term soy nut intake improved endothelial function, reduced LDL-cholesterol concentrations, and lowered mean arterial pressure.