Dietary enterolactone affects androgen and estrogen levels in healthy postmenopausal women

In this randomized dietary intervention study (DI) we analyzed levels of androgens, phytoestrogens, and estrogens in 12-h urine samples of 69 healthy postmenopausal women, 37 of whom followed a traditional Mediterranean diet for 6 months (intervention group) as compared to 32 women who followed their regular diet (control group). Circulating levels of both insulin and testosterone (T) were also assayed. Overall, enterolactone (ENL) was the most prominent phytoestrogen in urines of both control and intervention women, and its levels increased by a 20% after DI. At the baseline the ENL levels were seen to be significantly associated with both the total androgens (TOT-A) (r= 0.371, P= 0.002) and the TOT-A/total estrogen (TOT-E) ratio (r= 0.351, P= 0.005) in all 69 postmenopausal women. Furthermore, the DI resulted in a more pronounced negative association of both ENL with insulin (r=-0.321, P= 0.05) and insulin with TOT-A (r=-0.421, P= 0.01). Regarding urinary androgens, ENL associated with both 3alpha-androsterone (5alpha-androgen, r= 0.363, P= 0.002) and 3alpha-etiocholanolone (5beta-androgen, r= 0.295, P= 0.01) at baseline, while after DI, circulating insulin and T exhibited a significant negative association with the 5beta-androgen metabolite etiocholanolone (r=-0.487, P= 0.002; and r=-0.336, P= 0.042, respectively). We conclude that lignan components of the Mediterranean diet, notably ENL, are associated with urinary levels of products of androgen metabolism, including both 5alpha- and 5beta-reductase enzymes, in healthy postmenopausal women. Further studies are necessary to better understand the interplay of sex hormones with dietary phytoestrogens.