Another example of potential misunderstanding: it was stressed that findings from a recent metaanalysis and subsequently published studies show that neither isoflavone supplements nor isoflavone-rich soy products affect serum testosterone or estrogen levels in men, which according to the context was meant as a proof for the absence of feminizing effects [36], [39]. In a case report on gynecomastia associated with soy consumption by a man it was noted that after the patient stopped consuming soy products, ‘his breast tenderness resolved and his estradiol concentration slowly returned to normal’ [33]. It should be commented that, being estrogen analogues, phytoestrogens may exert estrogenic effects on their own independently of the levels of endogenous hormones.
