Sino-German Project on Soy Isoflavones

Phytoestrogens (PE) are a diverse group of plant-derived compounds that mimic mammalian estrogens both structurally and functionally. Some dietary isoflavones such as genistein and daidzein are quite outstanding comparing with others due to their higher level of estrogen receptor-dependent activity and higher concentration in soy food. Therefore these compoundsmay act as endocrine disruptors (EDs) by perturbing the delicate endocrine balance in vivo and possess adverse effects especially on the reproductive system and other estrogen-sensitive tissues.

Exposure to estrogenic substances during critical periods of development can have adverse consequences on differentiating estrogen-sensitive organs. Moreover, human fetuses and neonates can be exposed to high levels of isoflavones if their mothers consume excessive amounts of soy or if they are given soy-based formulas and other soy products marketed specifically for children. Therefore, due attention should be paid on the adverse impacts of dietary PE on health of infants, children and adolescents which are on one hand the group with the higher isoflavone exposure level per kg body weight on the other hand the individuals with a relative lower sexual-hormone level and a higher exogenous estrogenic substance sensitivity. Up to date, the involvement of dietary PE such as genistein and daidzein in human estrogen-sensitive organs’ development has not been conclusive.

Within a coordinated research project in cooperation with groups from Germany and China we are currently investigating the influence of dietary PE exposure during critical periods of development. The impact of PE on the development of the male and female reproductive and hormone sensitive tissues, metabolism and epigenetic modulations are studied in ratl models simulating different exposure scenarios. 

In the DKFZ subproject, we profile DNA methlyation changes in rodent tissue by 'Reduced Representation Bisulfite Sequencing' and Sequenom Epityper MassArray technology. Identification of DNA methylation changes is complemented by analyses of gene expression and functional investigations. 

Funded by DFG.