Among all cooking methods, boiling is the worst to cook vegetables like broccoli, cabbage, cauliflower and Brussel sprouts because it causes the biggest loss of anticancer compounds in these vegetables, according to a new study.

The noted vegetables contain a substance called glucosinolate that is metabolized into another compound known as isothiocyanate, which counteracts with cancer-causing effects of carcinogens and speeds up their removal from the body.

But boiling, the standard British cooking habits as researchers at the University of Warwick Medical School are cited as saying, leaches most of the beneficial compounds in these vegetables in a matter of 30 minutes, according to a study published in the journal Food Chemistry and Toxicology.

Paul Thornalley and Lijiang Song, authors of the study, report that the loss of glucosinolate varies with the type of a vegetable, 77 percent for broccoli, 58 percent for Brussel sprouts, 75 percent for cauliflower and 65 percent for green cabbage.

In contrast, other cooking methods cause no noticeable loss of glucosinolate, according to the researchers, cited by AFP.

Glucosinolate is also found in the same group of vegetables including kale, turnips, collard greens, rutabaga, Chinese cabbage, bok choy, horseradish, radish and watercress.