Association with equol production and effect of isoflavone treatment on bone mineral density and climacteric symptoms in Japanese women

The relationship between the effects of isoflavone supplementation on bone mineral density and climacteric symptoms and equol-producing ability was assessed by using a randomized trial of soy isoflavone treatment in Japanese women. A double-blind placebo-controlled crossover trial with an isoflavone supplement (IF) of 40 mg/d was carried out in 42 climacteric Japanese women. A questionnaire and an interview covered climacteric symptoms, health status, dietary and exercise habits, and medical history. The following measurements were made at baseline and after 4 and 8 wk of treatment: anthropometrical measurements, blood pressure, bone mineral density (BMD), blood status, and plasma biochemicals. Urinary isoflavones and metabolites were separately measured from refrigerated samples. The number of equol producers both at baseline and after IF treatment (P-P) was 17 (40.5%), of nonproducers at both periods (N-N) was 12 (28.6%), of producers at baseline who changed to producers after IF (P-N) was 7 (16.7%), and of nonproducers at baseline who became producers after IF (N-P) was 6 (14.3%). Urinary equol concentration was higher after IF treatment than after placebo treatment (P = 0.06). There was no significant difference in the average age of each group. The menopausal index score in the P-P group was lower (18 points) than in the other groups (26-31 points). The equol nonproducers at both baseline and after IF treatment had high body fat (30.1%) and high systolic blood pressure (148 mm Hg), and their BMD and climacteric symptoms did not improve with IF treatment. Women who became equol producers after IF treatment (N-P) showed lower plasma LDL at baseline (3.34 vs. 3.39-4.01 mmol/L) and greater improvement in BMD and climacteric symptoms ([+ or -] 0.14 g/[cm.sup.3], -5 points) compared with the other groups. Baseline anthropometric and cholesterol levels and effects of IF treatment on cholesterol, BMD, and climacteric symptoms differed according to equol-producing ability.