Rich in glucosinolates, sulfur-containing compounds. In two small Dutch feeding trials, men who ate about 300 grams of cooked Brussels sprouts a day, roughly two cups, for one to three weeks had higher blood levels of alpha-class glutathione S-transferase, one of the enzyme families the body uses to process foreign compounds (Bogaards and colleagues, Carcinogenesis 1994, ten men; Nijhoff and colleagues, Carcinogenesis 1995, five men and five women). In the five women the rise was not statistically significant, and for everyone it is an enzyme change, not a health outcome.