Soy intake and healthBMJ 2020; 368 doi: https://doi.org/10.1136/bmj.m247 (Published 29 January 2020) Cite this as: BMJ 2020;368:m247
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Potential adverse effects of abundant soy intake especially in the populations historically not adapted to soy have not always been in the foreground [1-5]. Derangements of the reproductive health and feminizing effects are regarded to be rare and mild  but may be statistically detectable in large populations.
Dysmenorrhea in women, mild change of gender roles in girls and gynecomastia in a man consuming soy products have been reported [2,6,7]. A cross-sectional study of 11,688 women showed that abundant intake of soy isoﬂavones was associated with an increased risk of lifetime nulliparity and nulligravidity . An association between soy exposure and early menarche was reported .
Experimental data demonstrate that soy isoflavones, also at doses and concentrations observable in humans including infants, can influence neuroendocrine pathways in animals of both sexes. Relevant doses of PhE have an impact on the differentiation of ovaries and fertility in animals [2,10,11]. Alterations of male sexual development and deficits of sexual behavior were noticed in rats and rabbits [12,13]. Moreover, some PhE e.g. genistein (present in soy) can exert androgenic effects , which is not surprising as PhE are plant substances with accidental similarity to human hormones, so that their effects are a priori unpredictable.
It was suggested that PhE are estrogen receptor modulators thus being different from estrogens . It is questionable, however, whether such modulations, also called endocrine disruption [2,16], are favorable for soy consumers, especially at a young age. Perinatal period, infancy, childhood and puberty are critical periods during which maturing systems are particularly sensitive to hormonal disruptions . As global soy consumption increases, greater awareness and consideration of the endocrine-disrupting properties of soy by nutrition specialists and other health practitioners are needed. Parents should be aware of possible estrogenic effects if they choose to feed their infants with soy-based formulas . More details are in .
1. Kurotan K., Takimoto H. Soy intake and health. BMJ 2020;368:m247
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Competing interests: No competing interests