Urinary equol excretion and its relation to serum lipid among healthy adults in Beijing

Objective To investigate levels and the physiological range of urinary excretion of equol and other metabolities of isoflavones,and to evaluate relations between equol phenotype and serum lipid and uric acid among adults in Beijing.Methods One hundred male and 100 female adults participated in a cross-sectional study and provided twice 24-hr urine samples on regular diet and after a 3 days soy isoflavone challenge,respectively.A health and demographics questionnaire,and 2 days food record were completed before the urine collection.Isoflavones and their metabolites in urine were measured to determine equol phenotype with HPLC.Results The percentage of the equol producer phenotype was 26.8% on regular diet and 60.4% after soy-isofavone challenge,respectively.The level of 24 hr urinary equol excretion was 5.75±11.02 μmol/24 hr on regular diet,and the level of equol excretion increased to 35.78±22.16 μmol/24 hr after soy-isofavone challenge among equol producers.There were positive correlations between soy protein intake,isoflavone intake and urinary equol levels(r=0.47,r=0.46,P<0.01).In those subjects who were identified as equol-producer phenotype,there were significant improvements in serum triglyceride and uric acid.Conclusion The equol-producing potential is high among healthy adults in Beijing.The result suggests that equol producer phenotype plays a potential protective cardiovascular role among the subjects.