The bad news is that one out of every three people in the United States will have some form of cancer during their lifetime. The good news is that an amazing array of compounds found in many whole vegetables, fruits, grains, beans and herbs has been shown to counteract numerous environmental carcinogens, both natural and human-made, to which we are often exposed. “Whole” is the key word, because while modern food processing allows manufacturers to ship and store foods for long periods of time, numerous life-giving and protective substances are removed along the way. In the mid-twentieth century, before food processing became widely practiced, people consumed many more foods in their whole state. This increased intake of fiber and phytochemicals may partly account for the lower incidence of certain kinds of cancers at that time.
The rise in cancer rates may also be associated with advanced screening methods. Additionally, only about half of the 75,000 compounds created in the chemist’s lab—chemicals that have entered our food and water—have been studied for any kind of human toxicity, so their carcinogenic potential is largely unknown.
Well-known cancer risk factors include smoking, alcohol, consumption of large quantities of animal fat, excessive sun exposure, certain chemicals in groundwater and foods, and asbestos. Here is a guide to some of nature’s most potent protectors found in fruits, vegetables, and other whole foods. Make sure to serve yourself and your immune system these foods daily.
Chlorophyll is said to have an immune-enhancing effect. It’s found in beet greens, bok choy, collards, dandelion greens, kale, mustard greens, nettles and chlorella and other blue-green algae.
Carotenoids. Many brightly colored vegetables have lutein, lycopene, and beta-carotene; carotenoids protect the delicate and vital fatty acids in your body from free-radical damage and can enhance immune response. Apricots, carrots, dark leafy greens, yams, squash, and tomatoes are good sources.
Anthocyanidins are thought to protect capillaries and other blood vessels as well as connective tissue from oxidative damage and promote collagen formation. Anthocyanidins are found in beets, blackberries, blueberries, cherries, red grapes (purple grapes are included in this category) and purple cabbage.
Sulfur compounds. Eating foods high in natural sulfur compounds may help attack and remove cancer-causing agents from your body, as well as improve estrogen balance; vegetables from the mustard family contain among the best cancer protectors known, such as sulforaphane. Broccoli, Brussels sprouts, cabbage, cauliflower, mustard greens, radishes and turnips are good sources.
Lutein. Related to the caro-tenoids (such as beta-carotene), lutein is an antioxidant that helps protect cells from the damaging effects of free radicals. Research suggests that lutein consumption may play a role in maintaining the health of the eyes, heart, and skin as well as the breasts and cervix in women. Lutein is not manufactured by the body, so you must get this nutrient in your diet from vegetables such as spinach, collard greens, kale, leeks, peas, and romaine lettuce—or from supplements in a dose of 6 mg daily, taken with food.
Lycopene, found in high concentrations in tomatoes (especially in cooked tomato products, such as spaghetti sauce), has been found to reduce the risk of prostate cancer, the most common cancer among men. It has also been shown to be a protective factor in other cancers, including those affecting the digestive tract and the esophagus. Lycopene is a potent antioxidant that prevents damage to DNA and helps keep cancer from forming. In one study, researchers noted a 40 percent reduction in the risk of esophageal cancer in people who consumed only one serving of raw tomatoes per week and a 50 percent reduction in cancer in all areas of the body among elderly people who had a high tomato intake in their diets. Although tomatoes have the highest percentage of lycopene, other food sources include watermelon, pink grapefruit, and guava juice. Lycopene is also available as a supplement.
One of the most potent cancer-fighters occurring naturally in food is a substance called resveratrol, which is found in the skins and seeds of red grapes. Also known for its ability to protect the heart, resveratrol works to prevent cancer cells from developing and growing in a variety of ways, which may be the key to its potent action. It is a compound that has been shown to help with the prevention of cancer, particularly in the early, reversible stage of the cancer process. While this research has sanctioned and encouraged drinking red wine, the same protective properties are obtained from drinking grape juice. Also, when you eat grapes, choose varieties containing seeds and chew and swallow them along with the pulp to receive maximum health benefits.
Grapeseed extracts are also available in capsule or tablet form. The seed extract contains antioxidant compounds called oligomeric proanthocyanidins (OPCs), which some researchers claim may slow down the aging process while protecting the skin and internal organs from the deleterious effects of stress and environmental toxins. Regular consumption of grape skin and seed extracts may help protect you from developing cancer.
Roots from Polygonum cuspidatum, commonly called Japanese knotweed, contain 20 percent resveratrol and have been shown in studies to prevent tumor growth in the lungs of mice. Ready-made dietary supplement products containing Japanese knotweed are widely available.
Interestingly, in the 1920s a naturopath from South Africa, Johanna Brandt, wrote a book called The Grape Cure about her experience healing herself from stomach cancer by eating grapes and drinking grape juice exclusively. The cure involved fasting for two to three days, then eating only grapes for a period of one week to two months. The grape cure was eventually utilized by other practitioners in European spas, and although it was labeled as quackery by many doctors, recent research confirms the preventive effects of grapes.
Green tea (Camellia sinensis)
Green tea is produced by lightly steaming the fresh tea leaves. Unlike black tea, which is also derived from Camellia sinensis and boasts healthful properties, green tea is not oxidized, so it retains more of the plant’s original compounds. Green tea has strong antioxidant and anticancer properties, and although it does contain some caffeine, it is not as stimulating as black tea or coffee. You can also buy decaffeinated green tea in bags or take it as a supplement in capsules. Green tea contains more of the beneficial astringent tannins—known as polyphenols—than black tea. It is this drying, “puckery” feeling in the mouth after drinking green tea that indicates that the main identified beneficial activities of tea are present and active. These potent antioxidant compounds are thought to offer significant protection against cancer by blocking the formation of cancer-causing agents. Studies have shown that the popular consumption of green tea may be one of the reasons why cancer rates are so low among Japanese people. A growing body of evidence in both human and animal studies suggests that regular consumption of green tea can reduce the incidence of a variety of cancers, including colon, pancreatic, stomach, and breast cancers. In a new study reported at the 1997 meeting of the American Chemical Society, the main polyphenolic constituent contained in green tea, epigallocatechin gallate (EGCG), seems to be twice as powerful as the resveratrol found in red wine in a cancer-prevention assay. The study compared the effects of EGCG, resveratrol, the antioxidants BHA and BHT, and vitamins E and C, finding that green tea was the most powerful protector.
The best medicinal mushrooms
Various mushrooms, such as shiitake (Lentinula edodes), reishi (Ganoderma lucidum) and maitake (Grifola frondosa), have immune-boosting properties to help the body avoid the formation of cancer cells. Researchers have identified very large sugar molecules called beta-glucans as a main active ingredient. All of these mushrooms are available in extract form in natural food stores, and some are available fresh. Incorporate these cancer fighters into your diet a few times a week as a tonic dose to support your immune system, or choose the extract for a stronger dose.
Shiitake. These mushrooms are not found in the wild in the United States but are widely cultivated. They are readily available in natural food stores and are quite delicious in stir-fries, soups, and tofu or egg scrambles (see recipe below). Shiitake is the source of two well-studied preparations with proven pharmacological effects—lentinan and LEM (short for Lentinula edodes mycelium) extract, both of which have demonstrated strong anti-tumor activity by enhancing various immune system functions. Because researchers at the recent International Conference on Medicinal Mushrooms in Kiev, Ukraine, reported that eating cooked shiitakes might be a good way to receive the healthy benefits of the mushroom, you may want to try the Tofu/Shiitake Scramble recipe often. May all your medicine be as yummy.
Maitake. These delicious mushrooms are commonly found in parts of the eastern United States, Europe, and Asia. Research suggests that when used consistently, maitake can aid in cancer prevention and immune stimulation. In China, an extract of this mushroom given orally for one to three months demonstrated an anticancer effect in sixty-three patients.
Reishi. This shiny fungus, known as ling zhi in China and reishi in Japan, has a shiny, varnished appearance and grows throughout the United States (most commonly on the East Coast) and in Europe, South America, and Asia. In recent years, successful cultivation of this mushroom has made it more readily available and affordable. Both in vivo and in vitro studies with reishi extracts have demonstrated anti-inflammatory, antioxidant, antitumor, and general immunopotentiating activity. Reishi is probably the most common medicinal mushroom found in tablet and liquid products throughout the world. It is available in natural food stores, herb stores, drugstores, and from Chinese herb dealers in a variety of preparations to counteract aging, improve energy levels, and for general health improvement.
Garlic and onions
Garlic and onions contain sulfur compounds, and there is no shortage of evidence regarding their immune-enhancing and tumor-inhibiting activity. In one study with 120,000 people over a three-year period, onion consumption was shown to inhibit the incidence of stomach cancer. Garlic has a plethora of healthy attributes, and one of its most significant clinical uses is cancer prevention. Various human studies have documented decreased cancer rates in populations with regular garlic consumption. One study demonstrated that garlic inhibits the formation of nitrosamines—cancer-causing compounds that form during the digestive process. Eating as little as one clove of garlic per day can confer protection, but be sure to crush it first before cooking or eating for optimum results. Try the popular recipes below to help you enjoy your medicine.
The old adage of letting your food be your medicine is definitely applicable in a discussion about cancer prevention. Making healthy choices from among the enticing array of colorful fruits and vegetables available to us translates into health insurance against cancer and a host of other diseases.
Beth Baugh has been the managing editor for ten books on botanical medicine and has been involved in the herb industry for almost thirty years. Christopher Hobbs, L.Ac., is the author of Herbal Remedies for Dummies (IDG, 1998) and many other books. Together, Christopher and Beth have recently completed an herbal correspondence course called Foundations of Herbalism; visit www.christopherhobbs.com .
For additional reading
Balch, James F. and Phyllis A. Prescription for Nutritional Healing. New York: Avery, 2000.
Dorant, E., et al. “Garlic and its significance for the prevention of cancer in humans: a critical view.” British Journal of Cancer 1993, 67(3): 424–429.
Fink, John M. Third Opinion. New York: Avery Penguin Putnam, 1997.
Franceschi, S., et al. “Tomatoes and risk of digestive-tract cancers.” International Journal of Cancer 1994, 59(2): 181–184.
Hess, David J. Evaluating Alternative Cancer Therapies: A Guide to the Science and Politics of an Emerging Medical Field. Piscataway, New Jersey: Rutgers University Press, 1999.
Jang, M., et al. “Cancer chemopreventive activity of resveratrol, a natural product derived from grapes.” Science 1997, 275: 218–220.
Jayasuriya, H., et al. “Emodin, a protein tyrosine kinase inhibitor from Polygonum cuspidatum.” Journal of Natural Products 1992, 55(5): 696–698.
Ji, H. T., et al. “Green tea consumption and the risk of pancreatic and colorectal cancer.” International Journal of Cancer 1997, 7: 255–258.
Kimura, Y., and H. Okuda. “Resveratrol isolated from Polygonum cuspidatum root prevents tumor growth and metastasis to lung and tumor-induced neovascularization in Lewis lung carcinoma-bearing mice.” Journal of Nutrition 2001, 131(6): 1844–1849.
Mitscher, L. “Chemoprotection: a review of the potential therapeutic antioxidant properties of green tea (Camellia sinensis) and certain of its constituents.” Medical Research Review 1997, 17(4): 327–365.
Moss, Ralph W. Antioxidants Against Cancer. Equinox Press, 2000.
Nanba, H. “Activity of maitake D-fraction to inhibit carcinogenesis and metastasis.” Annals of the New York Academy of Science 1995, 768: 243–245.\
Quillin, Patrick. Beating Cancer with Nutrition. Nutritional Times Press, 1997.
Yance, Donald R. Herbal Medicine, Healing & Cancer: A Comprehensive Program for Prevention and Treatment. New York: McGraw Hill, 1999.
Zeligs, M. “Diet and estrogen: the crucifer connection.” Journal of Medicinal Food 1998, 1(2): 67–82.