Effects of Dietary Phytoestrogens on Hormones throughout a Human Lifespan: A Review.

Nutrients. 2020;12(8)
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Phytoestrogens are polyphenolic molecules with a structural similarity to endogenous human hormones. The main dietary source of these plant secondary metabolites is legumes (particularly soy), and to a lesser extent fruits, vegetables, and cereals. The aim of this study was to synthesize the results obtained by human studies and assess the potential hormone-related health effects of dietary phytoestrogens throughout the human lifespan. Literature shows that: - the impact of phytoestrogens can vary according to the life stage. - soy isoflavones appear not to have any influence on sex and thyroid hormones, bone remodelling and insulin-like growth factor. - although phytoestrogens transfer from maternal blood to the foetus, no effects have been observed in early life. - in later stages of childhood, an increase of androgens and decrease of oestrogens associated with dietary phytoestrogens have been observed in girls and boys, respectively. - in adulthood, endocrine changes arising from phytoestrogen consumption are unclear, although goitrogenic [compounds that interfere with the normal function of the thyroid gland] activity has been observed in men. - in premenopausal women results regarding sex hormones, breast cancer protection and bone remodelling are uncertain. Authors conclude that intake of phytoestrogens does have some physiological effects in humans related to hormone regulation, but like hormones, the benefits depend on the stage of life.

Abstract

Dietary phytoestrogens are bioactive compounds with estrogenic activity. With the growing popularity of plant-based diets, the intake of phytoestrogen-rich legumes (especially soy) and legume-derived foods has increased. Evidence from preclinical studies suggests these compounds may have an effect on hormones and health, although the results of human trials are unclear. The effects of dietary phytoestrogens depend on the exposure (phytoestrogen type, matrix, concentration, and bioavailability), ethnicity, hormone levels (related to age, sex, and physiological condition), and health status of the consumer. In this review, we have summarized the results of human studies on dietary phytoestrogens with the aim of assessing the possible hormone-dependent outcomes and health effects of their consumption throughout a lifespan, focusing on pregnancy, childhood, adulthood, and the premenopausal and postmenopausal stages. In pregnant women, an improvement of insulin metabolism has been reported in only one study. Sex hormone alterations have been found in the late stages of childhood, and goitrogenic effects in children with hypothyroidism. In premenopausal and postmenopausal women, the reported impacts on hormones are inconsistent, although beneficial goitrogenic effects and improved glycemic control and cardiovascular risk markers have been described in postmenopausal individuals. In adult men, different authors report goitrogenic effects and a reduction of insulin in non-alcoholic fatty liver patients. Further carefully designed studies are warranted to better elucidate the impact of phytoestrogen consumption on the endocrine system at different life stages.

Lifestyle medicine

Fundamental Clinical Imbalances : Hormonal
Patient Centred Factors : Triggers/Phytoestrogens
Environmental Inputs : Diet ; Nutrients
Personal Lifestyle Factors : Nutrition
Functional Laboratory Testing : Not applicable

Methodological quality

Allocation concealment : Not applicable
Publication Type : Journal Article ; Review

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