Color Therapy: A Spectrum of Cancer-Fighting Foods
Jill E. Stansbury, N.D.
Many people's lives have been touched in some way by cancer. Maybe you've lost a relative, a friend or an acquaintance; maybe you had a scare as a result of an annual physical. But fortunately there are steps you can take to arm yourself in the fight against cancer. It is now common knowledge that proper diet and supplements can reduce the risk of this deadly disease.
Cancer is a prominent killer of Americans—second only to heart disease—and responsible for more than a half million deaths yearly. The good news is that scientific validation for the protective power of food is accumulating. And empowering people to preserve their health through daily choices puts responsibility in patients' hands.
So where do you start? A dizzying amount of information exists on cancer-preventing foods and supplements. The easiest step you can take is to modify your diet. By eating a rainbow of food colors or by emphasizing certain food groups, you will incorporate a variety of protective phytochemicals into your diet.
We are exposed to oxidizing- and cancer-producing substances daily, but compounds found in vegetables help limit free radicals and DNA damage caused by these carcinogens and therefore appear to lower the incidence of various types of cancer.
A Rainbow of Protection
Deeply pigmented plants appear to have important anti-inflammatory and antioxidant properties, and people who eat more of them have a decreased risk of cancer. Plant pigments also contain beneficial chlorophyll, carotenoids and bioflavonoids.
Green plants contain particularly large amounts of chlorophyll, which is a detoxifier and possibly an anticancer agent. Foods rich in chlorophyll include chlorella and other blue-green algae, beet greens, bok choy, collards, dandelion greens, kale, mustard greens and nettles. These greens—among the most nutritious of all plants or plant parts—also contain other diverse nutrients and healthy constituents. The blue-green algae family has a high chlorophyll content and has been credited with immune-enhancing effects including enhanced response to tumors and microbes. Chlorella powder, specifically, may reduce side effects of chemotherapy for some patients and may possess direct anticancer activities.
Orange, yellow and red-orange foods are rich in carotenoids such as beta-carotene, lutein and lycopene. These constituents are antioxidants and anticancer agents due to several different mechanisms.
More than 600 carotenoids occur naturally, but carotenes are the most widely known. Carotenes seem to offer protection against lung, colorectal, breast, uterine and prostate cancers. Carotenes, which destroy free radicals in lipids, enhance immune response and protect cells against UV radiation. Foods rich in these flavonoids include apricots, carrots, citrus fruits, squash and tomatoes in addition to many green foods.
The anthocyanidins are a type of complex flavonoid that produce blue, purple or red colors. Foods rich in these phytochemicals include beets, blackberries, blueberries, cherries, purple and red grapes, and purple cabbage. Anthocyanidins are beneficial in many ways. They contain anti-inflammatory properties, improve circulation, promote collagen formation, reduce cholesterol, work as antioxidants and appear to stabilize and protect capillaries. Thus, by eating these antioxidant pigments, some believe cancer risk can be reduced because the antioxidants protect against damage and help repair connective and vascular tissues.
Procyanidins are the precursors to anthocyanidins and are comprised of smaller units including catechins. These are simple flavonoids abundant in green tea. Several Japanese studies show that green tea consumption is protective against breast and other types of cancer.
Detoxifying, stimulating and spicy sulfur compounds are present in a variety of colorful foods including broccoli, garlic and pineapple. Sulfur-containing compounds in plants are believed active, or at least protective, against cancer because many pathogens are deterred by sulfur.
The crucifer family—which includes broccoli, Brussels sprouts, cabbage, cauliflower, mustard greens, radishes and turnips—has many sulfur-containing compounds as well as indoles, a subclass of phytonutrients that binds chemical carcinogens and activates detoxification enzymes, mostly in the GI tract. Indoles also improve estrogen balance, which may reduce the risk of estrogen-related cancers such as breast cancer.
Garlic (Allium sativum) and onions (A. cepa), both from the lily family, also contain sulfur compounds. Studies have shown the sulfur compounds in garlic oil and crushed garlic inhibit tumor metabolism and enhance immune response. The active compounds also enhance biochemical pathways involved in the liver's detoxification of carcinogenic substances. Furthermore, garlic also has immune-enhancing actions.
Pineapples contain bromelain, a sulfur-rich enzyme that has been investigated for antitumor effects. U.S. and French research shows oral bromelain can reduce cancer in animals. Some documented cases show cancerous tumors regressing as a result of bromelain therapy. Bromelain may also reduce the risk of cancer spreading. In vitro studies have shown bromelain therapy fights leukemia by normalizing blood cells and reduces lung cancer by impeding its spread.
Other protective phytochemicals include the caffeic, ferulic and ellagic acids, which have been shown to break down carcinogens. Caffeic and ferulic acids are found in green tea; ellagic acid is particularly plentiful in pomegranates and is also found in blueberries, grapes, raspberries and strawberries.
Limonene is a bioflavonoid substance found in citrus rinds that stimulates enzymatic liver reactions, which break down carcinogenic substances and prevent them from damaging cellular DNA. Another bioflavonoid, quercetin, is ubiquitous in onions, apples and black tea, and has been widely studied for its antioxidant, anticancer actions.
Whole-grain foods, rather than those derived from processed grains, are also worth emphasizing. Whole grains contain essential fatty acids (EFAs), which are important components of cell membranes.
Lignans, prominent in the woody parts of plants, are found primarily in rye and flax. They are believed to be converted into weak estrogens, which are absorbed across the intestinal walls from whence they travel to tissues and blood, binding with hormonal receptors. Like soy isoflavones, these estrogens may reduce excessive hormonal stimulation in tissues and reduce estrogen-related cancers.
Fiber is also thought to reduce cancer risk by binding carcinogens in the intestines and making a favorable environment for beneficial bacterial flora.
Legumes—especially soybeans—are another source of anticancer fiber, phytoestrogens, lignans and saponins. Soy also contains the isoflavones genistein and daidzein, which have been found to protect against estrogen-related cancers in numerous animal and epidemiological studies. Soy contains protease inhibitors that may inhibit the proliferation of cancer cells. Genistein in soy and in red clover diminishes the growth of new blood vessels in cancerous tissues.
Antitumor and anticancer properties also have been studied in mushrooms (see "The Spore with More"). shiitake (Lentinus edodes) and reishi (Ganoderma lucidum) have been found to promote general anticancer and immune-stimulating activity. Maitake (Grifolia frondosa) also contains immune-stimulating properties. In a Japanese study, mice were fed either a control diet, a diet that included 20 percent maitake powder or a control diet plus injections of maitake D-fraction extract. Results showed that maitake inhibited the spread of cancer by 81.3 percent in the maitake-fed group and by 91.3 percent in the D-fraction injection group.
Kelp and seaweed are also anticancer agents, which work like fiber by swelling in the intestines and absorbing liquid as well as toxins and heavy metals. Kelp and seaweed also may stimulate T cell production and function. Japanese studies show regular consumption of kelp reduces breast cancer risk. Furthermore, kelp extracts have been highly successful in inhibiting laboratory cancer strains.
Another place you may not expect to find cancer protection is on your spice rack. Cayenne pepper, ginger, rosemary, sage, thyme, turmeric and many others have anti-inflammatory, anticancer, immune-stimulating and antioxidant properties. Research suggests that curcumin the bright yellow flavonoid present in turmeric (Curcuma longa) roots, contains properties that selectively inhibit excessive inflammation.
Anticancer agents can be found in the supplements section as well as at the local produce stand. By emphasizing colorful fruits and vegetables, you can reduce your risk of cancer along with many other diseases.
Jill E. Stansbury, N.D., maintains a private practice in Battleground, Wash., where she specializes in botanical and natural therapies.