Endocrine and cognitive effects of short-time soybean consumption in women.
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.


OBJECTIVE
To observe the effects of 1 week of increased soybean intake on sex hormone levels and spatial cognitive abilities in women.


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.


CONCLUSIONS
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.
Celec
Peter
P
Institute of Pathophysiology, Faculty of Medicine, Comenius University, Bratislava, Slovakia. petercelec@hotmail.com
Ostatníková
Daniela
D
Cagánová
Marieta
M
Zuchová
Svetlana
S
Hodosy
Július
J
Putz
Zdenek
Z
Bernadic
Marián
M
Kúdela
Matús
M
D000328:Adult; D003071:Cognition / Q000187:drug effects*; D019587:Dietary Supplements / Q000600:supply & distribution*; D004958:Estradiol / Q000097:blood / Q000378:metabolism*; D005260:Female; D006801:Humans; D011581:Psychological Tests; D011863:Radioimmunoassay; D013025:Glycine max / Q000378:metabolism*; D013739:Testosterone / Q000097:blood / Q000378:metabolism*; D013997:Time Factors
D013739:Testosterone; D004958:Estradiol