I was no fan of broccoli when I was a kid. My mom used to have to serve it to me with melted cheese just so that I would eat it (pssst, don’t tell my mom, but I used to feed it to our family dog under the table before the cheese trick.)
Fortunately my taste has evolved and I love it now. This is a good thing, as I want to make sure I’m living the anti-cancer lifestyle…and eating brassicas (i.e. broccoli, kale, cabbage, etc.) is one powerful way to contribute to that.
There are two major anti-cancer phytonutrients found in brassica vegetables:
(see list of brassica veggies below):
- Indole-3-carbinol (I3C) and its metabolite bis(3′-indolyl)methane (DIM)
These 2 phytonutrients are members of a family of compounds called “isothiocyanates” (ITCs), and they have been shown to reduce the development and progression of cancer through a variety of mechanisms:
- Sulphoraphane helps to prevent the development of cancer by shutting-off crucial genes that are important in promoting the transformation of abnormal cells into cancer cells.
- Sulphoraphane reduces the number of cancer stem cells, considered the most difficult cell type in most cancers to eradicate.
- Sulphoraphane induces cancer cell death (apoptosis), blocks the formation of tumor blood vessels (antiangiogenic) and suppresses cancer cell metastases.
- Sulforaphane helps to promote the excretion of carcinogens from the body, reduces their formation in the body and boosts the genetic expression of detoxifying enzymes. (ref)
- I3C (and DIM) slow the growth of cancer cells and tumor by impairing cell cycle pathways, increasing cancer cell death (apoptosis) and blocking the formation of blood vessels to tumors.
- In one study, women with early stage cervical cancer (carcinoma in situ) received either a placebo pill or 200 mg of I3C per day for 12 weeks. Incredibly, 50% of the women taking I3C had complete resolution of their cancer by the end of the study! That’s enough for me to start recommending eating more brassicas (or supplementing with ITCs) for patients with human papilloma virus (HPV)-related cancers (or pre-cancerous lesions), like cervical cancer.
Fewer Cancers Develop In Brassica Eaters:
Numerous studies demonstrate large risk reductions of various cancers for those who consume the highest versus the lowest amounts of brassica vegetables.
Why You Should Chew Your Brassica Veggies:
One of the more incredible tidbits of vegetable trivia I’ve learned is that through the action of chewing on these brassica vegetables, the active anti-cancer ITC compounds, sulforaphane and I3C, are created. The diagram to the left shows how the inactive precursor molecule (glucosinolate) in the vegetable gets converted into the active anti-cancer compound (isothiocyanate) through the activity of a plant enzyme (myrosinase) that gets released from the plant cells when chewed!
Do You Juice?
To get the most nutrient value out of your vegetables and fruits, you should opt for a “masticating” juicer over a “centrifugal” juicer. Here’s why:
- A centrifugal juicer is the most common type of juicer you see in stores and on TV. A centrifugal juicer spins at high speeds and during the spinning motion, the vegetables that you have shoved down the chute are ground to a pulp. The spinning motion then forces the juice away from the pulp. The juice then pours into a bowl.
- Masticating means to chew, to grind or knead into a pulp.
Your teeth are an excellent example of mastication in action. Your teeth chew and grind food (which helps to the produce those anti-cancer ITCs if you are chewing on some broccoli.) A
masticating juicer uses an auger (gears) to slowly grind and crush your vegetables and literally squishes out the juice, which will give you a higher nutrient content (with a much greater chance of containing ITCs) than with a centrifugal juicer.
Learn Much More About Juicing & Blending On The Post Below (click the photo)
Examples of Brassica Vegetables:
- Bok choy
- Brussels sprouts
- Chinese cabbage
- Collard greens
- Daikon radish
- Land cress
- Mustard greens
- Shepherd’s purse
**In terms of conventional nutrients (vitamins, minerals, proteins, carbs, and fats), you will not find another vegetable group that is as high in vitamin A, vitamin K, carotenoids, vitamin C, folic acid, and fiber as the brassica vegetables.**
Raw Versus Cooked:
(summarized from WHFoods)
If you eat your brassicas raw, it’s best to eat it as fresh as possible. Research shows that the plant enzymes (i.e. myrosinase) and phytonutrients (i.e. ITCs) are much more active in the first 48 hours after being picked.
- Did you know that it takes 15 days, on average, to deliver produce from the farm to your supermarket? If you are looking to get the most out of natures anti-cancer phytonutrients, consider shopping at your local farmers markets or grow your own food.
If you consume your brassicas in cooked form, chop them up and let them sit in chopped form for several minutes prior to cooking. This allows myrosinase enzymes to go to work prior to their deactivation by cooking heats.
Steaming is superior to microwaving. In a study that compared steaming versus microwaving of raw cabbage, researchers found that it took 7 minutes of steaming to result in the same about of enzyme (myrosinase) destruction that occurred with only 2 minutes of microwaving. In other words, short steaming was much better than microwaving for preserving some myrosinase activity in the cabbage. Researchers in this study also found higher concentrations of ITCs in lightly steamed cabbage (steaming cooks foods at 212˚F/100˚C-a relatively low heat.)
Nutrient Content After Heating, Benefits of Eating Fermented Brassicas, Phytochemical Content of Various Brassicas:
Question (from Lisa H):
- “One question about the cooking methods. What about roasted broccoli and cauliflower – does this cooking method retain the anticancer qualities of the veg? Also, what are your thoughts on brocco sprouts – I have heard that they have more anticancer properties.”
Reply (from Conner):
- “Hi Lisa! Most cooking methods lower the amount of isothiocyanates (precursors to anti-cancer compounds) in brassicas. For instance, a 2008 study showed that while the sulforaphane in raw broccoli had a bioavailability of 37%, this dropped to only 3.4% when the vegetable was cooked. Different cooking methods have different effects; boiling results in the heaviest losses of cancer-protective compounds whereas (brief) steaming or microwaving has been shown to preserve them better. I can’t find any studies about roasting, but I suspect this will entail some loss, though it’s hard to quantify. (More research is needed!) Most studies I have seen recommend cooking brassicas lightly (e.g. steaming) and briefly – my rule of thumb is 5 minutes for broccoli florets and 1-2 extra minutes for cauliflower; I aim for “al dente”. As for broccoli sprouts, they contain up to 100 times more sulforaphane precursors than the mature plants. Moreover, as they’re eaten raw, nothings gets lost during cooking; that’s why I do recommend eating these regularly – e.g. in salads or sprinkled on soups.”
“I also recommend eating fermented (raw) cabbage like sauerkraut, which is also a excellent source of gut-health-promoting bacteria (probiotics). In a recent animal study cabbage juice – and particularly sauerkraut juice – induced key detoxifying enzymes that are thought to be involved in brassicas’ chemopreventive activity.”
- “You can really geek out on brassicas with the folks at the Linus Pauling Institute. Among others, Table 1 (above) article shows that Brussel sprouts contain by far the highest concentration of glucosinolates of all brassicas, with broccoli languishing in the lower half of the rankings. Of course, even the lower-ranked brassicas have value — red cabbage, for instance, contains 36 differrent antocyanidins. Who knew?! My advice: sure, eat broccoli, but don’t forget all the other yummy brassicas — like garden cress, turnips, mustard greens, kale, etc. Don’t look for anti-cancer miracle foods; as I write in Zest for Life, *variety* should be our mantra!”
Anti-Cancer Phytonutrient “Synergy”
One of the core principles of integrative oncology is the importance of consuming a diet with a wide-range of vegetables and fruits. It is thought that by combining a variety of these whole foods in the diet, their individual anti-cancer phytonutrients will be much more effective in preventing and inhibiting cancer cells than if consumed individually. This concept is referred to as “synergy” (i.e. 1+1+1 does not simply equal 3, but in fact may equal much more.) Cancer cells develop, grow and spread through numerous mechanisms. Just as with chemotherapy drugs, which kill cancer cells through a variety of pathways, natural anti-cancer phytonutrients have been demonstrated to function in many of the same ways (i.e. preventing cancer cell growth, signaling the cancer cell to die, preventing cancer cells from invading through tissues and reaching the blood stream or lymph nodes, preventing the growth of blood vessels that feed tumors, etc.)
Although I generally prefer that my patients obtain most of their anti-cancer nutrients through whole foods, there can be potential benefits of using supplements to obtain greater amounts of the anti-cancer phytonutrients (sulphoraphane, I3C, DIM and others) found in brassicas vegetables:
- It’s not easy to consume a large quantity of vegetables every day.
- It is important to consume a variety of brassicas, as they each contain different concentrations of these compounds.
- Heating methods all decrease the concentration of the active compounds…and eating raw brassicas does not suit everyone.
- Supplements can offer a consistent, high quality (as long as you do your research and buy high quality) source of these compounds in a convenient and efficient manner (pills, capsules, powders, etc.)
Additional References and Information:
Cruciferous Vegetables (Linus Pauling Institute): Tons of great information on cruciferous (also known as “brassica”) vegetables
Sulphoraphane (Examine.com): excellent compilation of references and studies
Juicing (American Cancer Society)
Juicing (Mayo Clinic)
Gerson Therapy (Gerson Institute)