INTRODUCTION

Equol, a gut microbiome-derived metabolite of soy isoflavone daidzein, functions as a selective estrogen receptor beta (ERβ) agonist. In preclinical studies, it has demonstrated vascular protective and antioxidant effects, with emerging evidence suggesting potential neuroprotective properties. However, its role in preventing vascular aging and cognitive decline in humans remains unexplored. The Arterial Stiffness, Cognition, and Equol (ACE) trial investigates whether daily equol supplementation can slow the progression of arterial stiffness, brain white matter lesions, and cognitive decline in older adults without dementia.

METHODS

ACE is a multicenter, randomized, double-blind, placebo-controlled clinical trial conducted at the University of Pittsburgh, Wake Forest University, and Emory University. Community-dwelling adults aged 65 to 85 years without dementia were enrolled and randomized 1:1 to receive either 10 mg/day of equol or placebo for 24 months. The primary outcome is arterial stiffness assessed by carotid-femoral pulse wave velocity. Secondary outcomes include white matter lesions detected on the brain magnetic resonance imaging and cognitive function as assessed by the Preclinical Alzheimer Cognitive Composite. Power calculations were based on a planned sample size of 400 participants, accounting for an anticipated 20% attrition rate.

RESULTS

A total of 1783 individuals were pre-screened, and 764 underwent in-person eligibility assessment. Of these, 369 participants were randomized into two groups: Arm A ( = 185) and Arm B ( = 184). The randomized sample self-reported as 52% women and 22% Black/African American participants. Baseline demographic and clinical characteristics were well balanced between the two arms, indicating successful randomization.

DISCUSSION

ACE successfully enrolled a racially diverse population of older adults and achieved near-target recruitment. ACE is the first large-scale trial to evaluate whether equol, a selective ERβ agonist, can impact vascular and cognitive aging, paving the way for precision nutrition strategies in dementia prevention.

HIGHLIGHTS

We detail the first randomized controlled trial of equol, an estrogen receptor beta (ERβ) agonist, for vascular and cognitive aging.The study tested equol's effects on arterial stiffness, white matter lesions, and cognition.The multisite trial enrolled 369 self-reported White and Black older adults aged 65 to 85 years.The trial investigated a novel dietary metabolite targeting ERβ pathways.