The cancer-fighting power of cruciferous vegetables

November 30, 2020 by Joel Fuhrman, MD

Health Concerns: Cancer

Looking for the most powerful cancer-fighting vegetables on the planet? Then feast your eyes (and of course, your body) on the plant foods that have demonstrated the most dramatic protection against cancer: the cruciferous family of vegetables. 

What are the cruciferous vegetables?

With their spicy, sometimes bitter taste (thanks to their glucosinolate content – more on that later), cruciferous vegetables add a depth of flavor to a healthy diet, in addition to their beneficial properties. The list of cruciferous veggies includes:  arugula, bok choy, broccoli, broccoli rabe, broccolini, brussels sprouts, cabbage, cauliflower, collards, horseradish, kale, kohlrabi, mustard greens, radish, red cabbage, rutabaga, turnips, turnip greens, and watercress. You’ll find almost all of them are included in my 100 Best Foods for Health and Longevity

What makes cruciferous vegetables so special?

The cruciferous family is unique among vegetables because of their glucosinolate content. When the plant cell walls are disrupted by chewing, chopping, or blending, the enzyme myrosinase converts glucosinolates to isothiocyanates (ITCs) or indole-3-carbinol. Scientific studies have uncovered cellular and molecular anti-cancer effects of these cruciferous phytochemicals, and a lower risk of cancer in people who eat these vegetables regularly. 

How to prepare & eat them

To get the maximum benefit from cruciferous vegetables, it’s important to make sure you chop finely, blend, or crush them before you cook them, or chew them well when eating them. That’s because the myrosinase enzyme is physically separated from the glucosinolates in the intact vegetables. But when the plant cells are broken apart, the chemical reaction occurs and ITCs are formed. The more cells you break open before cooking (or chew if you are eating the vegetables raw), the better. 

Once ITCs are formed, they will remain stable through the cooking process. Gut bacteria also have some myrosinase enzyme, so additional ITC production from glucosinolates in cooked cruciferous vegetables may occur after we eat them. Also, we can increase ITC production from cooked cruciferous vegetables by having some shredded raw cruciferous vegetables such as cabbage, kale, collards or arugula in a salad in the same meal to supply the myrosinase enzyme, which the body can use during the digestive process.1-3

Sources:
Disposition of glucosinolates and sulforaphane in humans after ingestion of steamed and fresh broccoli
Hydrolysis before Stir-Frying Increases the Isothiocyanate Content of Broccoli
Isothiocyanates from Brassica Vegetables-Effects of Processing, Cooking, Mastication, and Digestion

Reduced risk of cancer in cruciferous consumers

Higher intake of cruciferous vegetables is linked to a reduced risk of cancers of the lung, ovary, stomach, breast, prostate, and colon.4-8

Sources:
The Role of Cruciferous Vegetables and Isothiocyanates for Lung Cancer Prevention: Current Status, Challenges, and Future Research Directions 
Intake of cruciferous vegetables is associated with reduced risk of ovarian cancer: a meta-analysis
Cruciferous vegetables intake and the risk of colorectal cancer: a meta-analysis of observational studies
Cruciferous vegetable consumption and gastric cancer risk: a meta-analysis of epidemiological studies
Cruciferous vegetables intake is inversely associated with risk of breast cancer: a meta-analysis


Related: Ten strategies to prevent prostate cancer

How cruciferous phytochemicals work9,10

  • Anti-inflammatory effects: ITCs have been found to decrease the secretion of inflammatory molecules.
  • Anti-angiogenic effects: Isothiocyanates can inhibit the development of new blood vessels to limit tumor growth.
  • Detoxification of carcinogens: Some carcinogens must be converted to their active form before they can bind DNA to cause carcinogenic changes – isothiocyanates inhibit this transformation. 
  • Preventing DNA damage: Isothiocyanates also increase the production of our body’s natural detoxification enzymes, which protect DNA against damage from carcinogens and free radicals. 
  • Stopping cell division in cells whose DNA has been damaged.
  • Preventing proliferation and promoting programmed cell death in cancerous cells 
  • Stimulating interferon production: Diindolylmethane (DIM), formed from indole-3-carbinol, stimulates interferon production, which is part of the body’s antiviral and anti-tumor response. 
  • Anti-estrogenic activity: Exposure to estrogen is known to increase breast cancer risk; estrogens can alter gene expression, promoting cell proliferation breast tissue. ITCs and indole-3-carbinol have been shown to inhibit the expression of estrogen-responsive genes.
  • Shifting hormone metabolism: Eating cruciferous vegetables regularly helps the body to shift hormone metabolism, reducing the cancer-promoting potency of estrogen and other hormones.

Sources:
Cruciferous vegetables and human cancer risk: epidemiologic evidence and mechanistic basis 
3,3'-Diindolylmethane stimulates murine immune function in vitro and in vivo

Anti-estrogenic effects of cruciferous vegetables

Indole-3-carbinol (abundant in broccoli, Brussels sprouts and cabbage) and ITCs have anti-estrogenic effects, help the body excrete estrogen and other hormones.11 In fact, new research has shown additional anti-estrogenic effects of both indole-3-carbinol and sulforaphane (most abundant in broccoli); these ITCs blunt the growth-promoting effects of estrogen on breast and cervical cancer cells.11-13

Studies have found breast cancer survivors who eat cruciferous vegetables regularly have a lower likelihood of cancer recurrence.14,15 

Sources:
Anti-estrogenic activities of indole-3-carbinol in cervical cells: implication for prevention of cervical cancer 
Indole-3-carbinol is a negative regulator of estrogen receptor-alpha signaling in human tumor cells 
Regulation of estrogen receptor alpha expression in human breast cancer cells by sulforaphane 
Cruciferous Vegetable Intake After Diagnosis of Breast Cancer and Survival: a Report From the Shanghai Breast Cancer Survival Study 
Vegetable intake is associated with reduced breast cancer recurrence in tamoxifen users: a secondary analysis from the Women's Healthy Eating and Living Study 

Related: Ten strategies for preventing breast cancer

Cruciferous vegetables in randomized controlled trials

In healthy people, randomized controlled trials have found decreases in oxidative stress or increases in antioxidant enzymes after consumption of cruciferous vegetables.16-19

Sources:
Phase 1 study of multiple biomarkers for metabolism and oxidative stress after one-week intake of broccoli sprouts 
Reduction of oxidative DNA-damage in humans by brussels sprouts 
Effect of broccoli intake on markers related to oxidative stress and cancer risk in healthy smokers and nonsmokers
Watercress supplementation in diet reduces lymphocyte DNA damage and alters blood antioxidant status in healthy adults

Reduced cancer-related biomarkers have been found in randomized controlled trials on supplementation with cruciferous vegetables or their extracts in patients with prostate cancer or breast cancer.20-23 

Sources:
Effect of Sulforaphane in Men with Biochemical Recurrence after Radical Prostatectomy 
Broccoli consumption interacts with GSTM1 to perturb oncogenic signalling pathways in the prostate 
Effect of Cruciferous Vegetable Intake on Oxidative Stress Biomarkers: Differences by Breast Cancer Status 

Action items

Position Paper: Preventing and Treating Cancer
Video on Demand: How to Prevent Breast Cancer (free for members)
Explore health concern: Cancer
Recipe: Kale Onion Chips (A Fuhrman family favorite!)
Recipe: Spiced Butternut and Brussels Bowl (Autumn on a plate!) 
 

 

Joel Fuhrman, M.D. is a board-certified family physician, seven-time New York Times bestselling author and internationally recognized expert on nutrition and natural healing, who specializes in preventing and reversing disease through nutritional methods. Dr. Fuhrman coined the term “Nutritarian” to describe his longevity-promoting, nutrient dense, plant-rich eating style.
 
For over 25 years, Dr. Fuhrman has shown that it is possible to achieve sustainable weight loss and reverse heart disease, diabetes and many other illnesses using smart nutrition. In his medical practice, and through his books and PBS television specials, he continues to bring this life-saving message to hundreds of thousands of people around the world.

 

Comments (0):

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sharine777

12/02/2020 03:51 PM

Excellent article, Dr. Fuhrman, and thank you for your work! Cauliflower is my favorite vegetable. I could (and often DO) eat it every day! Second on my list is broccoli, which my husband and I steam and eat almost like a full meal, same as with my third fave, brussels sprouts. I'm excited to try a new recipe shared by a friend, Creamy Cauliflower Wild Rice Soup; it's made with cashew cream, yum!😋

scbury11 replies:

12/03/2020 07:55 AM

That sounds wonderful Sharine. Just found a recipe online. Dr Fuhrman would be proud. Itis exactly how he says you should eat. Stay safe.

gaiasu

12/02/2020 04:30 PM

Great review Dr Fuhrman. A good reminder to prep

our foods with a purpose! Gerard and Susan MacPhee Canada

scbury11

12/03/2020 07:56 AM

What a very informative article. Thank you so much, Dr Fuhrman. 

phyllis143

12/05/2020 04:38 PM

Just what I was looking for! Thank you Dr. Fuhrman for this valuable information.