"The Irish researcher, Smyth, has measured the thyroids of Breast Cancer patients and found swollen thyroids indicates risk for breast cancer."
Lots of folks who had/have Breast Cancer did not have swollen thyroids. So, it can be equally states that a lack of a swollen thyroid also indicates risk for breast cancer, nullifying predictive value of Smyth's statement re thyroid swelling as a sole indicator. I don't discount his work as I know not of it, only that broad statement, absent knowledge of other factors present, and in every case I've looked at, the researchers nearly always overlook pertinent facts, usually because their funding depends on them making particular conclusions.
Don't over look the benefits of sulforaphanes in brassicas.
Cassava has a high cyanogenic glycoside content, which is metabolized to thiocyanate by rhodanese - there's the "goitrogen" from cassava. Populations whose diets contain cassava regularly are among the lowest with cancers in the world, because of beta glucosidase.
DIM , in addition to modulating hormone metabolism, has beneficial effects on elimination of metals and undesirable halogens. Those who don't believe it can have at it and collect their piss and analyze it and come back and tell me what I already know. Read all the double blind studies you want, or go real.
The word "goitrogen" is most often used by those having little knowledge of any of this. It's an impressive-sounding word, that villifies all kinds of stuff, kind of like medicoiodophobia did to iodine. Humans seem predisposed to that sort of thinking. W. Reich explained why this is the case. Had to read it 4 times before it made full sense.