[Isoflavone-containing dietary supplements].
Isoflavones (IFs) from soy and other legumes have weak estrogenic properties. Isolated IFs are available as dietary supplements and advertised to alleviate symptoms of menopause. The present chapter provides an overview of the occurrence, the chemical structure of IFs and their metabolites, the market situation and reviews the current evidence on the efficacy and safety of IF-containing dietary supplements.The biological effectiveness of IFs is attributable to the activation of the estrogen receptor (ER). Studies on the influence of IFs on endogenous estrogen levels in women show inconsistent results. So far, the European Food Safety Authority (EFSA) has rejected all submitted health claims for IFs due to insufficient scientific evidence for any of the postulated health effects. Based on the results of their recent risk assessment, the EFSA concluded that the available human studies did not support the hypothesis of adverse effects of isolated IFs on the human mammary gland, uterus or thyroid in healthy postmenopausal women. However, the assessment does not allow a general statement on the safety of IF-containing dietary supplements. Studies in animal models are often not comparable with the complex interactions in humans due to differences in the metabolism of IFs, in the developmental stage at time of consumption and in the temporarily restricted uptake of IFs during certain stages of life.


CONCLUSIONS
So far, for none of the advertised functions is unequivocal scientific evidence available. On the basis of available data, potential unwanted side effects cannot be fully excluded. This holds particularly true for women with undiagnosed diseases, especially for those with undetected precancerous lesions in the mammary gland.
Institut für Pharmazie und Lebensmittelchemie, Julius-Maximilians-Universität Würzburg, Würzburg, Deutschland.
Leane
L
Lehmann
Institut für Sicherheit und Qualität bei Obst und Gemüse, Max Rubner-Institut, Karlsruhe, Deutschland.
Sebastian T
ST
Soukup
Epigenomik und Krebsrisikofaktoren, Deutsches Krebsforschungszentrum, Heidelberg, Deutschland.
Clarissa
C
Gerhäuser
Institut für Zoologie, Technische Universität Dresden, Dresden, Deutschland.
Günter
G
Vollmer
Institut für Sicherheit und Qualität bei Obst und Gemüse, Max Rubner-Institut, Karlsruhe, Deutschland. sabine.kulling@mri.bund.de.
Sabine E
SE
Kulling
D019587:Dietary Supplements / Q000009:adverse effects*; D019317:Evidence-Based Medicine; D005260:Female; D019584:Hot Flashes / Q000628:therapy*; D006801:Humans; D007529:Isoflavones / Q000008:administration & dosage* / Q000009:adverse effects*; D048789:Phytoestrogens / Q000008:administration & dosage* / Q000009:adverse effects*; D016896:Treatment Outcome
D007529:Isoflavones; D048789:Phytoestrogens
Dietary supplements; Estrogenicity; Isoflavones; Menopausal symptoms; Safety