By Joel Fuhrman, M.D.
Cruciferous vegetables include green vegetables like kale and broccoli plus some non-green vegetables like cauliflower and turnips. They are named for their flowers, which have four equally spaced petals in the shape of a cross — the Latin word ‘crucifer’ means ‘cross-bearer’.
Nutrition scientists have repeatedly shown that eating natural plant foods decreases the risk of cancer. All vegetables contain protective micronutrients and phytochemicals, but cruciferous vegetables are uniquely powerful — in fact, twice as powerful as other plant foods.
In population studies, a 20 percent increase in plant food intake is associated with a 20 percent decrease in cancer rates, but a 20 percent increase in cruciferous vegetable intake is associated with a 40 percent decrease in cancer rates.1 Inverse associations between cruciferous vegetable intake and breast, lung, prostate, pancreatic, and colorectal cancers have been reported.2
Isothiocyanates. The potent anti-cancer activity of cruciferous vegetables can be traced to unique molecules called isothiocyanates (ITCs). These protective molecules are responsible for the pungent or bitter flavors of these vegetables. Chopping, chewing, blending, or juicing cruciferous vegetables makes ITCs more available for us to digest and absorb.
If we want to cook cruciferous vegetables, we can get more ITC benefit if we chop them before cooking. In recent years, scientists have begun to study the protective roles of ITC against various cancers.
Anti-cancer activities. All plant foods contain beneficial phytonutrients — many of these are antioxidants. For example vitamin C, beta-carotene, and lycopene reduce oxidative stress in the body. But only cruciferous vegetables can produce ITCs, whose beneficial properties reach far beyond antioxidant activity. These compounds are our best defense against environmental carcinogens. Over 120 ITCs have been identified, and different ITCs can work in different ways and in different locations in the cell.
Several ITCs can work synergistically, having various anti-cancer effects. The anti-cancer activities of ITCs may include anti-inflammatory or antioxidant effects. Some ITCs can prevent cancer cells from growing and multiplying. Other ITCs detoxify and/or remove carcinogenic compounds from the body. Others can prevent carcinogens from binding to DNA and initiating cancerous changes in the cell. Some can cause cancer cell death. Certain ITCs act on hormones, and these may be especially protective against hormone-sensitive cancers like breast cancer.2
Sulforaphane is an ITC found in broccoli and Brussels sprouts. Sulforaphane activates enzymes that prevent DNA damage, allows the body to excrete certain dietary carcinogens, and stops growth and induces death in cultured cancer cells.
New research has shown that allyl isothiocyanate (AITC) slows tumor growth in animals, and that indole-3-carbinol (I3C) may prevent tumors from acquiring a blood supply3-4. AITC and I3C are both found in several cruciferous vegetables. Like other nutrients, these molecules are most beneficial when they are ingested as part of a whole food, not when isolated and taken in supplement form.
Nutrient density. Cruciferous vegetables are not only the most powerful anti-cancer foods on the planet, they are also the most nutrient-dense of all vegetables. These vegetables are rich not only in ITCs, but also vitamins, minerals, antioxidants, and other health-promoting phytonutrients. I recommend 8 total servings of vegetables per day including 2 servings of cruciferous vegetables — one raw and one cooked. These ITC-rich cruciferous vegetables provide a profound level of protection against cancer and other chronic diseases.
Cruciferous vegetables include arugula, bok choy, broccoli, broccoli rabe, broccolini, brussels sprouts, cabbage, cauliflower, collards, horseradish, kale, kohlrabi, mache, mustard greens, radish, red cabbage, rutabaga, turnips, turnip greens, and watercress.
Try this recipe to add more cruciferous vegetables to your diet — you can find an extensive collection of delicious and satisfying recipes like this in Dr. Fuhrman’s most recent book, Eat for Health!
Mediterranean Bean and Kale Sauté
2 bunches kale, tough stems and center ribs removed, chopped
1/2 cup sun-dried tomatoes, covered with water, and soaked at least one hour, chopped
1 medium onion, finely chopped
1 cup shiitake or oyster mushrooms, coarsely chopped
3 cloves garlic, pressed
1 tablespoon Dr. Fuhrman’s VegiZest or other no salt seasoning blend
1 cup cooked beans, any type, or canned, no salt added
1 1/2 tablespoons Dr. Fuhrman’s Riesling Raisin Vinegar or other sweet vinegar
1 tablespoon Dijon mustard
red pepper flakes, to taste
tomato based pasta sauce, as desired
In a large skillet, water sauté the kale, tomatoes, onion, mushrooms and garlic in a little water over medium heat for 5 minutes, adding water as needed. Add VegiZest, and enough water to keep from scorching. Cover and steam for 10 minutes. Add the beans, vinegar, mustard and red pepper flakes, cook for 3 more minutes or until mushrooms are tender and liquid cooks out. Stir in pasta sauce.
Dr. Fuhrman is a best-selling author and board certified family physician specializing in lifestyle and nutritional medicine. Visit DrFuhrman.com. Submit your questions and comments about this column directly to firstname.lastname@example.org.
1. Michaud DS et al. Frut and vegetable intake and incidence of bladder cancer in a male prospective cohort. J Natl Cancer Inst 1999; 91(7):605-13
2. Higdon JV et al. Cruciferous Vegetables and Human Cancer Risk: Epidemiologic Evidence and Mechanistic Basis. Pharmacol Res. 2007 March ; 55(3): 224-236
3. Bhattacharya A et al. Inhibition of Bladder Cancer Development by Allyl Isothiocyanate. Carcinogenesis. 2009 Dec 2. [Epub ahead of print]
4. Kunimasa K et al. Antiangiogenic Effects of Indole-3-Carbinol and 3,3’-Diindolylmethane Are Associated with Their Differential Regulation of ERK1/2 and Akt in Tube-Forming HUVEC. J. Nutr. Vol. 140, No. 1, 1-6, January 2010