Equol and Vascular Function in Women With Chronic Kidney Disease

Inclusion Criteria: * Postmenopausal women * Aged ≥50 years * CKD stage 3 or 4 (eGFR with the CKD-EPI 2021 race-free equation: 15-59 mL/min/1.73m2; stable renal function in the past 3 months) * Low habitual intake of soy (soy-related food intake \< 2 times per week assessed by Soy-Specific Food Frequency Questionnaire) * Weight stable in the prior 3 months (\<2 kg weight change) and willing to remain weight stable throughout the study * Ability to provide informed consent. Exclusion Criteria: * Patients with advanced CKD requiring chronic dialysis * Uncontrolled hypertension in CKD group (BP \>140/90 mmHg) * Use of any hormone replacement therapy * Allergy and/or intolerance to soy or soy-based products * Aspartate aminotransferase (AST), alanine aminotransferase (ALT), or total bilirubin values 2X upper limit of normal range (upper limit of normal range AST: 117 U/L; ALT: 52 U/L; total bilirubin: 1.3 mg/dL) * History of breast cancer * Significant co-morbid conditions with a life expectancy of \< 1 year * Current tobacco or nicotine use or history of use in the last 12 months * History of kidney transplant * History of severe congestive heart failure (i.e., ejection fraction \<35%) * History of hospitalization within the last month * Immunosuppressant agents taken in the past 12 months * Known malignancy