Fig. 5.

(a) Selenium compounds in cancer prevention. (b) Methylated selenium compounds. Methylated selenium compounds have been shown to modify various biological processes including suppression of angiogenesis and cancer prevention. Se ingested as Se-Met may follow the transsulfuration pathway, converted to Se-Cys and then cleaved to produce selenide. In contrast, Se-methyl selenocysteine (SeMSC) may be converted to methyl selenol by cleavage of the Se-methyl group. The chemical form of Se found in broccoli is similar to that found in Se garlic and the inhibition of carcinogenesis seems to be a consequence of the uniqueness of Se in those plants and not a consequence of the total intake of Se, garlic or broccoli.