Broccoli. The leaves and stem of broccoli, Brassica oleracea italica, are an excellent source of calcium, phosphorus, potassium, vitamin A and vitamin C. Broccoli also contains the additional nutrients protein, fiber, iron, thiamin, riboflavin, niacin, folic acid and biotin, as well as bioflavonoids 1. Many of these nutrients have antioxidant properties.
Recent attention has been devoted to an additional component of cruciferous vegetables, namely, the glucosinolates. Glucosinolates are biologically inactive, sulfur-containing compounds that can be broken down in the human gastrointestinal tract. Isothiocyanates, including sulforaphane, are the biologically active metabolites of glucosinolates that can then be absorbed through the intestine 2. Broccoli has a high glucosinolate content compared to other cruciferous vegetables, and broccoli extracts have a particularly high concentration of sulforaphane 3, 4.