Prenatal exposure to flavonoids - Short- and long-term effects

Abstract

Flavanoids are plant polyphenols and widely distributed in fruits and vegetables. They are well-known antioxidants and due to claimed health benefits they are also commercially available as dietary supplements. Unfortunately, the potentially toxic effects of an excessive flavonoid intake are largely ignored. Since flavonoids readily cross the placenta and are even able to accumulate, the unborn fetus may be particularly at risk when the maternal diet contains an excessive amount of flavonoids. Moreover, during this critical and sensitive period of early life, imbalances in maternal nutrition and exposure to certain compounds(e.g.flavonoids) can lead to short-, as well as long-term effects, a phenomenon known as fetal programming. Preliminary data from our department indicated that prenatal exposure to flavonoids could induce long-term hematological changes. This led us to further investigate the short- as well as long-term effects, a phenomenom known as fetal programming. Preliminary data from our department indicated that prenatal exposure to flavonoids could induce long-term hematological changes. This led us to further investigate the short- and long-term effects of a prenatal exposure to the ubiquitous flavonoids quercetin and genistein. Because flavonoids are more than just dietary antioxidants and are also able to inhibit topoisomerase II, we investigated whether prenatal exposure to flavonoids was associated with an increased cancer risk later in life. In this study, we observed that a prenatal exposure to flavonoids lead to an accelerated maturation of the erythroid lineages during fetal development and an altered blood composition in adult mice, with differences between the two flavonoids. This underlines the heterogeneity of the plant polyphenols and their pleiotropic effects. Furthermore, only mice that were prenatally exposed to genistein were observed to have a higher risk for developing tumours. These data warrant further investigations into the role of dietary flavonoids during pregnancy and the mechanisms by which they affect developmental and postnatal erythropoiesis and their role in cancer. Ultimately, since we observed potentially harmful effects of a prenatal flavonoid exposure and because they are being increasingly consumed either via the diet or supplementation, it is important to raise public awareness about the detrimental effects of flavonoids.