Broccoli was developed in Italy and is well established as one of the major anti-cancer foods. Over the past 20 years, numerous studies have concluded again and again that people who eat an abundance of broccoli have fewer cancers of the colon, breast, cervix, lungs, prostate, esophagus, larynx, and bladder. Broccoli contains indoles, which can help inactivate harmful estrogens that can promote the growth of tumors, sulforaphane, which stimulates cells to produce cancer-fighting enzymes, and beta-carotene, another cancer fighter.
Broccoli contains some 3% of protein and is one of the richest vegetable sources of calcium, iron and magnesium. Moreover, broccoli is very rich in vitamins A and C, exceeding even oranges in the concentration of the latter.
Taken from: http://health.learninginfo.org/broccoli-nutrition.htm