Broccoli is high in vitamin C and dietary fiber. It also contains
multiple nutrients with potent anti-cancer properties, such as
diindolylmethane and small amounts of selenium.A single serving
provides more than 30 mg of vitamin C and a half-cup provides 52 mg
of vitamin C. The 3,3'-Diindolylmethane found in broccoli is a
potent modulator of the innate immune response system with
anti-viral, anti-bacterial and anti-cancer activity.
Broccoli also contains the compoundglucoraphanin, which can be
processed into an anti-cancer compound sulforaphane, though the
anti-cancer benefits of broccoli are greatly reduced if the
vegetable is boiled.Broccoli is also an excellent source of
indole-3-carbinol, a chemical which boosts DNA repair in cells and
appears to block the growth of cancer cells.
Boiling broccoli reduces the levels of suspected anti-carcinogenic
compounds, such as sulforaphane, with losses of 20–30% after five
minutes, 40–50% after ten minutes, and 77% after thirty minutes.,
However, other preparation methods such as steaming,microwaving,
and stir frying had no significant effect on the compounds.
Broccoli has the highest levels of carotenoids in the brassica
family. It is particularly rich in lutein and also provides a
modest amount of beta-carotene.