Equol producing status affects exercise training-induced improvement in arterial compliance in postmenopausal women.

Central arterial compliance decreases drastically after menopause. Regular intake of soy isoflavone and aerobic exercise increase arterial compliance. The equol is a metabolite of isoflavone daidzein by gut microbiome. We determined whether the equol producing status affects aerobic exercise-induced improvement in carotid arterial compliance. Forty-three postmenopausal women were assigned to two intervention groups: 1) exercise and isoflavone (Ex + Iso, n=27) or 2) isoflavone interventions (Iso; n=16). Participants of the Ex + Iso intervention group completed an 8-week aerobic exercise training, and all participants were administered with oral isoflavone supplements during the interventions. The equol-producing status (equol producers or non-producers) were determined from urine equol concentrations after a soy challenge. In the Ex + Iso intervention group, carotid arterial compliance increased in the equol producers (0.084±0.030→0.117±0.035 mm2/mmHg) but not in the non-producers (0.089±0.028→0.097±0.026 mm2/mmHg) after the intervention (interaction effect; p<0.05). The magnitude of increases in carotid arterial compliance was significantly greater in the equol producers than in the non-equol producers (p<0.05). In the isoflavone intervention group, there were no changes in any parameters after the intervention irrespective of the equol status. These results suggest that equol-producing status is obligatory to aerobic exercise training-induced improvements in central arterial compliance in postmenopausal women.