Estrogen + breast cancer currently on chemo is it ok to drink a protein drink sometimes that has soy in it?

Best to avoid excess: In general soy intake should be limited in women. There is really no science to guide us as to how much soy is too much. We do know that soy products act estrogen like in our bodies. Probably best to limit amount of soy products. Now if you only take one shake a day and don't consume other soy products you are definitely ok.

Probably.: Much interest and research o0n phyto Estrogens in soy products. No convincing clinical studies to contra indicate soy in diet- especially if occasional use. Check to see the content of soy- if it is the predominant source for the protein and you are worried don't. If your chemo is anti estrogen or aromatase inhibitor, even less data.