Especially in social media, soy is conspicuously often associated with feminization of men. This is often based on individual case reports or animal studies. The scientific data is thin and conflicting, but observational studies and clinical studies do not give cause for concern.
A technical review from 2021 evaluated 417 studies on the possible hormonal effects of soy. Of these, 229 were observational studies, 157 clinical studies and 32 systematic reviews or meta-studies. The authors conclude that soy:
- does not have a negative effect on the thyroid gland,
- has no negative impact on breast tissue,
- has no negative impact on the estrogen balance of women,
- has no negative influence on the testosterone balance in men,
- has no negative impact on sperm quantity or quality
- no negative influence of isoflavone intake in children could be determined.
The scientists conclude that based on the data, isoflavones cannot be classified as endocrine disruptors. Lately we have presented a video from Emma Thorne, where she debunks a YouTuber talking about how “evil” soy is. She was wondering why this myth is still around. Some time ago Hbomberguy has made some videos about it and we see where the myth is coming from: