Endocrine and Cognitive Effects of Short-Time Soybean Consumption in Women

Abstract

Background: Soy phytoestrogens are known to influence the hormonal status acting as partial estrogen agonists. Soy-derived food supplements are advised for hormone replacement therapy, prevention of atherosclerosis, age-related cognitive decline and even hormone-dependent cancer, although results from clinical studies are controversial. Whether increased soybean intake can affect the endocrine status and cognitive abilities is largely unknown. Aim: To observe the effects of 1 week of increased soybean intake on sex hormone levels and spatial cognitive abilities in women. Subjects and Methods: 16 young healthy female volunteers were asked to eat 900 g of soybeans within 1 week. Salivary testosterone (T), free and total plasma T, salivary and plasma estradiol (E) were measured by radioimmunoassay before and after the study period. Mental rotation (MR) and spatial visualization (SV) psychological tests were done at the days of sampling. Results: Soybean intake increased total plasma T levels (p < 0.02) while decreasing salivary T (p < 0.01) and not altering free plasma T levels. Salivary and plasma E levels were not changed. The results of MR and SV tests were improved after the study period. Conclusion: Short-time increased soybean intake alters the level of total plasma and salivary T and improves spatial cognition in women. Whether this effect is mediated by modulation of estrogen receptors, changes in sex hormone-binding globulin production or changes in activity of steroid-competent enzymes needs further study.

Increased one week soybean consumption affects spatial abilities but not sex hormone status in men

“…In our previous study, we have shown that short-term increased soybean intake influences the endocrine status and improves spatial cognitive performance in premenopausal women (Celec et al 2005). The aim of this study was to prove whether short-term increased soybean intake affects sex hormone levels and cognitive status in men.…”

Isoflavones: Chemistry, Analysis, Functions and Effects on Health and Cancer

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