Intake of phytoestrogens and estrogenic effect of the diet of female university students in Mexico

Abstract

Phytoestrogens are components naturally occurring in plants and include many foods that are part of the regular diet of animals and humans. Phytoestrogens are xenoestrogens of plant origin that are not produced in the endocrine system. Phytoestrogens can act as either agonists or antagonists, depending on their tissue concentrations and the levels of endogenous estrogens at various life stages. The aim was to evaluate the intake of phytoestrogens and the estrogenic effect of the diet of women at university in Chihuahua (Mexico). In total, 400 female university students individually filled out a food frequency questionnaire (FFQ) that included 120 foods. Estimates of the intake of phytoestrogen (genistein, daidzein, biochanin A, formononetin, matairesinol, coumestrol, enterolactone, secoisoresinol, enterodiol) in the subjects’ daily diet were based on published reports. Quantification of phytoestrogens was expressed in μg day−1. The estrogenic effect of those compound identified according to the foods consumed was estimated using the in vitro E-SCREN test. SPSS v.22.0 (IBM, Chicago, IL, USA) was applied for statistical analysis following descriptive analysis and stepwise regression. p < 0.050 was taken as significant. The results of intake show that the majority of isoflavones are formononetin (median 110.60 (μg day−1) and their estrogenic activity is 4.11 Eq. E2 (pmol day−1); the majority of lignans are enterolactone (median 147.24 (μg day−1), and their estrogenic activity is 4.94 Eq. E2 (pmol day−1). The total phytoestrogen estrogenic effect is measured in pM of E2, with a mean of 28.28 (SD = 23.97) and median of 21.50. The mean consumption of phytoestrogens in Mexican university students is similar to the consumption found in similar studies in the United States, England, Germany, and Spain (<1 mg day−1). Phytoestrogens can be beneficial in adult women during perimenopause and menopause due to their estrogenic effects, but they are less recommended for women in the fertile stage, as, for example, in the study presented here, because they could function as endocrine disruptors. They are not recommended as dietary supplements for young women or pregnant women.