How Isothiocyanates Help Protect Against Cancer

The Physicians Committee

How Isothiocyanates Help Protect Against Cancer

Carcinogens are the bad guys of the cancer battle. They are the chemicals that cause the disease. Isothiocyanates (pronounced eys-so-thigh-o-sigh-an-ate) stop them dead in their tracks in three different ways: 1) They don't allow carcinogens to be activated; 2) they counteract the poisonous effects of carcinogens that have been activated; and 3) they speed up their removal from the body.1

Isothiocyanates have been shown to be especially effective in fighting lung and esophageal cancers.2-4 Studies have shown that risks of other cancers of the gastrointestinal tract and the respiratory tract can also be reduced by consuming isothiocyanate-rich vegetables.5

Food Sources

Isothiocyanates can be found in cruciferous or "cabbage family" vegetables such as broccoli, cauliflower, kale, turnips, collards, Brussels sprouts, cabbage, kohlrabi, rutabaga, Chinese cabbage, bok choy, horseradish, radish, and watercress.1,2,5

These vegetables add crunch or flavor to many of our familiar dishes, such as coleslaw, vegetable stir-fry, collard greens, and salads. While many people readily enjoy these cruciferous vegetables, some find them a little bitter. In fact, studies have found that some people are "supertasters" and tend to dislike bitter foods because their tastebuds are more sensitive to them.1 If you are one of these people, experiment with different ways of preparing these vegetables—such as slow-cooking kale or collards or adding a little lemon or vinegar—to make them more appetizing to you. They are too valuable for the prevention of cancer to avoid.

Tips for Increasing Isothiocyanates in Your Diet

  • Add broccoli, cauliflower, or any other of the other cruciferous vegetables to stir-fries, soups, stews, and sauces.
  • Munch on raw broccoli or cauliflower for a snack.
  • Boost your salad's cancer-fighting potential by adding watercress, kale, cabbage, or collard greens.
  • Use rutabagas or turnips in place of potatoes in your favorite potato dish.
  • For a portable meal, include cruciferous vegetables in a veggie wrap.

1. Drewnowski A, Gomez-Carneros C. Bitter taste, phytonutrients, and the consumer. Am J Clin Nutr. 2000;72:1424-1435.
2. Cinciripini PM, Hecht SS, Henningfield JE, Manley MW, Kramer BS. Tobacco addiction: implications for treatment and cancer prevention. J Natl Cancer Inst. 1997;89:1852-1867.
3. London SJ, Yuan J-M, Chung F-L, et al. Isothiocyanates, glutathione S-transferase M1 and T1 polymorphisms, and lung cancer risk: a prospective study of men in Shanghai, China. Lancet. 2000;356(9231):724-729.
4. Hecht SS. Inhibition of carcinogenesis by isothiocyanates. Drug Metab Rev. 2000;32:395-411.
5. Edens NK. Representative components of functional food science. Nutr Today; July 1999. Retrieved on May 24, 2001 from database,