Spring is upon us, and with it comes the prospect of new beginnings with flowers blooming and trees, plants, and bushes budding with the fruits and vegetables of the season. The warm breeze of spring brings motivation to start the “spring cleaning” of our diets. There is no better way to shape up a diet than to start incorporating more cruciferous vegetables into the diet.
Cruciferous vegetables include such nutrition superstars as broccoli, cauliflower, kale, arugula, watercress, bok choy, cabbage, collard greens, and brussels sprouts. Cruciferous vegetables belong to the Brassicaceae family, and all of these vegetables share the same 4-petal construction resembling its namesake the “cross” or “crucifer.” Some cruciferous vegetables have a “head” like broccoli and cauliflower, and others are “headless” like kale and collard greens. The impressive vitamin, mineral, and phytochemical content of cruciferous vegetables is undeniable, and their impact on disease prevention, especially cancer prevention, has been the focus of many research studies. The unique phytonutrient content of these vegetables has been shown in epidemiologic studies to help prevent the onset and halt the progression of colon, breast, prostate, bladder, cervical, and other cancers.1,2
Every day, we are exposed to pollutants that our bodies must fight. Exposure to these pollutants can be a result of choices we make in our lives such as the foods we eat or a result of factors outside of our control such as elements in the environment that adversely affect our health. Cruciferous vegetables have been shown to help eliminate these toxins from our body and reduce their negative impact, thereby reducing the risk of certain chronic diseases. The ability of cruciferous vegetables to help protect our bodies from chronic disease is due to their sulfur-containing compounds called glucosinolates.
Once one of these vegetables is altered by chewing, cutting, or chopping, specific plant enzymes are activated and initiate the breakdown of the glucosinolates into biologically active compounds called indoles and isothiocyanates.3 Because of the presence of these compounds, detoxification enzymes are stimulated and begin the process of eliminating carcinogens in the body before they can damage DNA.3,4 These compounds have been the focus of many types of research studies evaluating their impact on cancer prevention as well as the prevention of other chronic conditions.
Breast cancer has been the focus of many studies investigating the impact of the phytochemicals found in cruciferous vegetables on its prevention as well as on reducing the risk of breast cancer recurrence. The isothiocyanates and indoles found in cruciferous vegetables have been shown to alter estrogen metabolism, shifting the estrogen from a stronger, active form to a weaker, less active form.5 This may help reduce the risk of hormone-based cancers such as breast as well as endometrial and cervical cancer.5 According to the American Institute for Cancer Research (AICR), more recent, well-designed studies do not strongly or consistently support a link between cruciferous vegetable intake and reduced cancer risk.6
The lack of evidence to support the positive impact of cruciferous vegetables on cancer reduction may be due to genetic differences from person to person. The AICR reports that scientists have discovered that some individuals are unable to “retain” or "utilize” the protective phytochemicals present in cruciferous vegetables, which ultimately inhibits their ability to initiate the detoxification process.6 At this time, it is still beneficial to encourage breast, endometrial, and cervical cancer patients to include 3 to 5 servings of cruciferous vegetables a week in their diet. In addition to the phytochemicals present in cruciferous vegetables, they are also rich in fiber, carotenoids, vitamin C, and folate.
Researchers continue to investigate the effect and impact of cruciferous vegetable intake on various cancer sites. Based on recent research, bladder cancer survival may be improved with the intake of cruciferous vegetables. In an in vivo study, researchers found that isothiocyanates in broccoli sprout extracts were able to inhibit bladder tumor formation in rats by 61%.7 These studies show the potential impact of phytochemicals on a specific organ site. This is valuable information to utilize when developing an individualized dietary plan that can actually make a significant impact on the patient’s health. Additional support for the intake of cruciferous vegetables to reduce cancer risk comes from a review of case-control studies from Italy and Switzerland. This review concluded that the studies examined suggested there is a “favorable effect” of cruciferous vegetables on cancers of the oral cavity/pharynx, esophagus, colorectum, breast, and kidney.8
Increased fruit and vegetable intake is protective against many different chronic diseases, including cancer. As health professionals, we constantly encourage patients to increase their intake of these health-promoting, disease-fighting foods. This is a health message that has been touted for years, and the wisdom of those words is now becoming clearer. Science is evolving and diving deeper into the human body’s metabolism of plant phytochemicals and how well our bodies are able to utilize their biologically active compounds. Research may even be able to tell us exactly which cruciferous vegetable is most protective against a particular type of cancer and if an individual is genetically capable of utilizing those compounds effectively.
Eating your vegetables has never held as much meaning as it does now, with emerging research revealing their strength and power on our health. At times it may seem too simplistic to tell patients to consume more vegetables to improve their health. However, a simple truth may be all they need to make significant changes to their overall well-being. Three to 5 servings per week of broccoli, cauliflower, kale, collard greens, brussels sprouts, cabbage, or bok choy can help reap the benefits of these nutrient-packed vegetables. Enjoy them prepared in a variety of ways such as steamed or sautéed, or eat them raw. Because of their high fiber content, patients who are having issues with abdominal bloating, diarrhea, or nausea may have difficulty tolerating these vegetables.
Once symptoms resolve, these vegetables can be slowly reincorporated into the diet. If patients are currently under treatment, it may not be feasible for them to consume as many of these vegetables as recommended due to a variety of side effects caused by treatment. It is still important to share these dietary recommendations with patients as it empowers them, provides them with options and a means to improve their well-being, and even augments the treatment prescribed by their doctors. Bottom line: eat your veggies!
- Bosetti C, Filomeno M, Riso P, et al [published online ahead of print February 10, 2012]. Cruciferous vegetables and cancer risk in a network of case-control studies. Ann Oncol.
- Liu B, Mao Q, Lin Y, et al [published online ahead of print March 6, 2012]. The association of cruciferous vegetables intake and risk of bladder cancer: a meta-analysis. World J Urol.
- Holst B, Williamson G. A critical review of the bioavailability of gluco - sinolates and related compounds. Nat Prod Rep. 2004;21:425-447.
- Talalay P, Fahey JW. Phytochemicals from cruciferous plants protect against cancer by modulating carcinogen metabolism. J Nutr. 2001;131(11 suppl):3027S-3033S.
- Auborn KJ, Fan S, Rosen EM, et al. Indole-3-carbinol is a negative regulator of estrogen. J Nutr. 2003;133(7 suppl):2470S-2475S.
- American Institute for Cancer Research. Foods that fight cancer: broccoli & cruciferous vegetables. www.aicr.org/foods-that-fight-cancer/broccoli-cru ciferous.html. Accessed March 30, 2012.
- Munday R, Mhawech-Fauceglia P, Munday CM, et al. Inhibition of urinary bladder carcinogenesis by broccoli sprouts. Cancer Res. 2008;68:1593-1600.
- Tang L, Zirpoli GR, Guru K, et al. Intake of cruciferous vegetables modifies bladder cancer survival. Cancer Epidemiol Biomarkers Prev. 2010;19:1806- 1811.
Spring Asian Salad
2 heads of mizuna, cut from stem
2 heads of tatsoi, cut from stem
1 cup baby arugula
½ lb daikon, julienne
¼ cup mandarin oranges
¼ cup cucumber, sliced
6 cherry tomatoes, quartered
2 tablespoons ginger, chopped
2 cloves garlic, chopped
1 bunch scallion, sliced thin
1 tablespoon sesame oil
¼ cup lite soy sauce
- Toss together first 7 ingredients.
- Whisk remaining ingredients.
- Toss salad with dressing.
Yield: 4 servings
110 calories, 6 g fat, 0.5 g saturated fat, 0 mg cholesterol, 520 mg sodium, 11 g carbohydrate, 2 g dietary fiber, 6 g sugar, 5 g protein
2 bunches collard greens, about 4 cups
4 garlic cloves, chopped
2 onions, diced
4 tablespoons salt-free herb seasoning
1 teaspoon hot sauce
- 1. Cut collard leaves from stem. Cut leaves to small dice.
- 2. Wash leaves by soaking in a bowl of cold water. Remove greens from water and transfer to new bowl. Repeat this process until the bottom of the wash bowl comes out clean.
- Simmer in water for 20 minutes until tender.
- Chill in ice water.
- Heat sauté pan and add cooking spray. Sauté onions for 5 minutes until soft.
- Add garlic and sauté an additional minute.
- Add collard greens and heat through.
- Add seasoning and hot sauce.
Serving size: 1/2 cup
40 calories, 0 g total fat, 0 g saturated fat, 0 mg cholesterol, 50 mg sodium, 9 g total carbohydrate, 2 g dietary fiber, 2 g sugar, 2 g protein
Napa/Bok Choy Slaw
1 head napa cabbage, chiffonade
1 head bok choy, chiffonade
2 carrots, julienne
1 bunch scallions, sliced thin
2 garlic cloves, chopped
½ cup rice wine vinegar
¼ cup canola oil
2 tablespoons sugar
¼ teaspoon salt
- Toss all the ingredients together.
- Mixture can be used immediately, or it can sit overnight and be served the next day.
Serving size: 1/2 cup
70 calories, 4.5 g total fat, 0 g saturated fat, 0 mg cholesterol, 95 mg sodium, 5 g total carbohydrate, 1 g dietary fiber, 3 g sugar, 1 g protein