Nutrients
Broccoli is an excellent source of vitamins K, C, and A, folic acid and dietary fiber. It’s a very good source of phosphorus, potassium, magnesium, and vitamins B6 and E.

Glycemic Index (GI)
In a study to determine the GI of various foods, it was concluded that broccoli has a low GI of 15.

Cataracts
Research at the Harvard School of Public Health in Boston has concluded that the carotenoids present in broccoli and spinach, and the consumption of these vegetables, are associated with a lower risk of cataracts.

Cancer
One of the American Cancer Society's key dietary recommendations to reduce the risk of cancer is to include cruciferous vegetables such as broccoli.
Sulforaphane is an isothiocyanate, an organic chemical compound that has been shown to inhibit the growth of carcinogen-induced cancer. Sulforaphane is found in cruciferous vegetables and is especially high in broccoli, and more so in broccoli sprouts.
In a study at the Mount Sinai School of Medicine in New York, results clearly demonstrated the effect of sulforaphane in arresting the growth of human ovarian cancer cells.
High isothiocyanate intake from broccoli and other cruciferous vegeatbles may also reduce breast cancer risk.
Research conducted at The Johns Hopkins University School of Medicine concluded that sulforaphane inhibits the bacteria helicobacter pylori, which is a major cause of gastric infection. These infections are known to cause gastritis and peptic ulcers, and increase the risk of gastric cancer.
In a study involving1338 patients with prostate cancer, it was concluded that high intake of broccoli and other cruciferous vegetables, may be associated with reduced risk of aggressive prostate cancer.
Indole-3-carbinol conjugates are phytochemicals present in cruciferous vegetables such as broccoli, and studies have shown them to have anti-cancer properties.
In a study at the International Agency for Research on Cancer in France, results demonstrated the protective effect of cruciferous vegetable consumption on lung cancer.
Cruciferous vegetable intake has also been associated with a decrease in gastrointestinal and bladder cancers.