Actually, raw broccoli is not necessarily more healthful than cooked. Broccoli is part of the cruciferous vegetable family and great food to include in your diet either raw or lightly cooked. These vegetables provide many nutrients but their unique contribution is a group of compounds called glucosinolates. When we chew or chop these vegetables, glucosinolates are exposed to an enzyme stored elsewhere in the plant that converts these inactive compounds to isothiocyanate compounds which studies suggest may reduce cancer risk.
The latest research shows that you can get high amounts of these protective compounds if you blanch the vegetables first. Blanching is a quick dip in boiling water, followed immediately by cooling. You can also preserve both nutrients and the enzyme needed to form protective isothiocyanates if you steam broccoli for three or four minutes (just until crisp-tender) or microwave for less than one minute.
Especially if you won’t be consuming the cooking liquid (as in soup), boiling broccoli—or other cruciferous vegetable—is not the optimal method. Boiling leaches out the vegetable’s water-soluble vitamins in these vegetables, such as vitamin C and folate, as well as many of the glucosinolate compounds, which are water-soluble, too. Moreover, too much exposure to high temperatures destroys the enzyme that converts the inactive glucosinolates to active compounds. Serving broccoli raw is an excellent option, since it retains these nutrients and the enzyme that forms isothiocyanate compounds. Before serving on a relish tray or salad, quickly blanching and cooling allows you to get even a bit more of these compounds. When you want cooked broccoli, steaming or very brief microwaving are excellent choices.