When it comes to researching the link between diet and cancer, broccoli may be the most studied vegetable. It is well established that people who eat more fruits and vegetables have lower rates of certain cancers. But the group of vegetables called cruciferous vegetables, and broccoli in particular, seem to have strong anticancer properties on their own. Broccoli contains sulforaphane, an isothiocyanate and powerful anticancer substance. But that's not the only compound that might be acting to prevent cancer. Broccoli contains fiber, flavonoids, indoles, vitamins and minerals that may also play a role in disease prevention.
The way you cook broccoli impacts the healthy compounds that end up on your plate. The best cooking methods are microwaving and pressure cooking. Boiling and steaming seem to reduce the content of healthy compunds, like sulforaphane and vitamin C. How long you cook also matters. Three to four minutes is optimal. Longer cooking or cooking at high temperatures can prevent enzymes from converting compounds in broccoli to the cancer-fighter compound sulforaphane. It's also a good idea to eat broccoli that's as fresh as possible. Healthy compounds degrade over time and can be reduced to very low levels with extended storage.
Broccoli sprouts may be even more effective at fending off cancer than full grown broccoli. The sprouts seem to be a much richer source of the glucosinolate cancer-fighter than broccoli. Extracts of broccoli sprouts were tested in rats susceptible to bladder cancer and were found to reduce the number and size of tumors. If you can find broccoli sprouts in your grocery store, they are an easy way to get healthy compounds into your diet.
So, how much and how often do you need to eat broccoli to reap the benefits? Broccoli is an all-around healthy food rich in vitamins, minerals, fiber and phytochemicals that may help prevent cancer. You can count broccoli toward your daily goal of four to six cups of fruits and vegetables. When it comes to cancer prevention, there are no specific recommendations yet for how much broccoli or other cruciferous vegetables are needed to get the benefit. However, the levels of sulforaphane that have been effective in research studies equates to eating broccoli at least two or three times per week.