A good diet often translates into good health. One type of cancer that is most associated with a diet poor in fiber is colorectal cancer. Colon and rectal cancers are the number two cancer killers in the U.S. Certain lifestyle habits have been associated with a higher risk of these diseases:
There are a number of things that can be done to reduce the risk of colorectal cancer, including eating more fruits, vegetables and dietary fiber, increasing exercise, maintaining a healthy weight and getting regular health screenings. According to Isaac Eliaz, M.D., a cancer specialist who uses both Western and Eastern approaches to medicine, of Amitabha Medical Clinic and Healing Center (Sebastopol, Calif.), supplements of folic acid, vitamin D3 and calcium also may have a beneficial effect.
Research shows that many of the recommendations addressing colon cancer can be used to reduce risk of other types, as well. Particularly, eating plenty of fruits and vegetables is helpful, while diets high in fat are linked to an increased risk of breast, colon, prostate and, possibly, pancreatic, ovarian and endometrial cancers.
Fruits and VegetablesAs evidence mounts in favor of functional foods, there has been a realization that a synergy of natural phytochemicals in our foods helps protect us from disease. As fiber is now in the news again, food formulators have come full circle in their efforts of "reconstructing the fruit"? in order to provide a more palatable, yet nutritious, superfood.
There are many ubiquitous phytochemicals in fruits and vegetables that are important for our health, such as Co-Q10 (also called ubiquinone), known for its cardiovascular and antioxidant benefits, and quercetin. Quercetin recently has been found to show anti-cancer benefits. Our guts have a layer of cells that line the walls, creating a layer of mucus. This layer acts as a defense against external pathogens. Over time, as this layer is sloughed off and renewed continually, it also is subject to developing mutations in the cells.
Ian Johnson, head of Gastrointestinal Health and Function at the Institute of Food Research (Colney, Norwich, U.K.) explains that the flavonoid quercetin, present in many fruits and vegetables, can inhibit the enzymes called COX-2 that help mutated cells to survive, reducing cancer risk.1
An increased understanding of phytochemicals has shed light on synergistic compounds in vegetables, such as the newly discovered synergy between the phytochemicals sulforaphane and apigenin, which help eliminate mutated epithelial cells in the digestive tract.2 Such synergistic interactions undoubtedly will be important in the future, as functional food formulators strive to deliver the benefits found in nature.
Dietary Fiber and GrainsAccording to Johnson, typical American diets tend to have a high caloric intake without enough protective substances such as fiber, folate, polyunsaturated fatty acids, plant chemicals (such as glucosinolates or flavonoids) and gut fermentation products (such as butyrate). Increasing evidence points to high-fiber diets as being cancer-preventive. Johnson adds that colorectal cancer is both a disease of affluence and diet, as about 80% of the cases are attributed to an unhealthy diet.1
Dietary fibers available for food applications range from prebiotic inulins to traditional guar gum to resistant starches. As functional foods have become popular with consumers, food companies are launching brands that feature healthful ingredients. For example, Kellogg's (Battle Creek, Mich.) has a new cereal brand called Muddles, which provides 2g of inulin (more than one-third of the recommended daily serving) in one serving of cereal.
In vegetarian women, there was a relative risk of .85 in developing colorectal cancer when compared to non-vegetarians. Recent research also shows that women who eat high-fiber diets have lower risks of developing post-menopausal breast cancer. Diet-related factors in the development of this disease include obesity and regular alcohol intake of .3
Upping Antioxidantscancer. Antioxidants are a large category with numerous compounds, such as the bioflavonoid pigments found in plants and green tea; the vitamins A, C and E; and minerals such as selenium.
In a review of the literature on cancer risk reduction by antioxidants, Block and Evans concluded that "antioxidants and other nutritional supplements would appear to have potential for the most profound benefit in reducing the risk of certain identified diseases, such as cancer, in these populations where adequate antioxidant plasma levels and intake are not achieved through appropriate dietary sources." Among the diseases reduced by antioxidant supplementation were prostate, cervical, oral, gastric, esophageal, skin and lung cancers. Some commercially available compounds have carefully been researched for their benefits in this area.
For instance, lycopene, the pigment molecule and antioxidant present in tomatoes, has been found to reduce the size of fibroid tumors in animal studies. Several other studies also have found that lycopene may prevent or even slow the progression of certain cancers, including prostate cancer.
Recent research has shown that lycopene helps to stimulate production of phase II detoxification enzymes that are regulated by an "antioxidant response element" or ARE.
Everyone's old favorite, vitamin C, has been found to protect against cancers of the esophagus, oral cavity, stomach and, possibly, the pancreas, rectum and cervix.
Vitamin A and carotenoids have been associated with reducing the risk of certain cancers, especially lung cancer. Studies including smokers have demonstrated that those consuming carotenoid-rich foods had a reduced risk of lung cancer.
Vitamin D deficiency has been coined the new epidemic among adolescents and is due, in part, to a decrease in milk consumption and exposure to sunlight. Among the potential dangers and results of this deficiency are various bone problems and the development of certain types of cancers. (See "Folate Not Just for Babies Anymore," ? October 2004, p. 59.)
Recently, at least one study showed that foods rich in vitamin E, such as olive oil, nuts, spinach and mustard greens cut the risk of bladder cancer in half. This disease is the fourth leading cancer killer among men. Prior studies have been conducted on alpha-tocopherol in smokers' diets, and its ability to protect against lung and other cancers. Vitamin E's role in cancer-prevention is not yet thoroughly established in that there also have been many studies that show it has no effect, making vitamin E's role in cancer unclear.
Minerals to TeaOne of the most notable minerals for cancer prevention is selenium, which also is an antioxidant. The supplementation of 200mcg/day of selenium for people living in the U.S. in areas of selenium-deficient soil has resulted in an overall cancer mortality rate reduction of 21%, with prostate cancer being reduced by 65%.5
Calcium also may be an important cancer-preventative in the diet. The consumption of 700mg of calcium daily has been found to significantly reduce the risk of developing colon cancer for both men and women.6
Women with this level of calcium consumption had a 27% reduction in distal colon cancer, and men had a 42% reduction. Although milk often is touted as the best food source of calcium, even better sources are turnip greens, mustard greens, collard greens and tofu (processed with calcium).
One of the most widely consumed beverages on a worldwide basis, tea has been the subject of numerous studies for its chemopreventive benefits. Tea contains the antioxidant catechin, which is thought to be a prime chemopreventive compound. In earlier animal studies, catechins reduced the size of tumors and scavenged oxidants before they damaged the cells. Clinical studies in humans thus far have been inconclusive; however, this is probably due to variances in the diets, populations and environments studied. Tea is implicated in the prevention of numerous types of cancers, and the National Cancer Institute (Bethesda, Md.) is investigating it for its therapeutic and preventative ability in cancers, including skin cancer.
Soy Protein and GenisteinThe FDA is reviewing a petition for a health claim suggesting soy protein-based foods are able to reduce the risk of certain cancers, including those of the breast, prostate, uterus and colon, as these are the areas in which clinical research has found soy to be most effective.
In some exciting new research on the benefits of men eating soy products, it has been found that diets high in soy may prevent both baldness and prostate cancer. Soy compounds can be converted into a hormone-like compound called equol. Equol is a natural and powerful blocker of dihydrotestosterone, or DHT. DHT is known to promote male-pattern baldness, as well as prostate cancer growth.7 More research indicates genistein-concentrated polysaccharide can reduce the levels of prostate-specific antigen (PSA) in "watchful waiting"? patients.8 PSA often is used as an indicator of prostate cancer growth and metastasis.
Regularly eating soya-rich foods recently has been reported to also decrease the risk of uterine cancer in women.9 As soya-rich foods previously have been linked to reducing breast cancer, these results are exciting because they add to the mounting evidence that isoflavones' estrogen effect, including genistein, may be beneficial in fighting heart disease and cancer.
Other Supplements and the Integrative ApproachA promising supplement and food ingredient for cancer prevention and treatment is Modified Citrus Pectin (MCP). MCP is a type of citrus pectin specially processed to limit the size of the pectin molecules, allowing them to be absorbed easily into the bloodstream. In clinical trials, MCP reduces the size of tumors, prevents metastasis and reduces any blood capillary formation in tumors, halting the development of cancer. MCP also has shown promising results as a gentle chelator of heavy metals.10 According to Isaac Eliaz, M.D., MCP may play an important adjunctive role in cancer, as heavy metal toxicity often is linked to the cause or acceleration of pathological illnesses, such as cancer.
Eliaz also has respect for less conventional, but very traditional approaches. Eliaz says that medicinal mushrooms are important in his treatment of cancer patients. "For my patients, I use a mixture of the ancient medicinal mushrooms that have been used for millennia in traditional Chinese medicine. They act as immune enhancers, and show powerful anti-cancer properties." Most of these medicinal mushrooms also are considered foods, and are being confirmed by science to bolster the immune system.
He adds that, "Prevention and treatment of cancer requires an integrative approach. Simple lifestyle changes: regular walking, proper restorative sleep, hydration with a good water source, and a healthy diet, can have long-term and far-reaching benefits. When those simple lifestyle changes are combined with conventional therapies, they make both conventional and alternative therapies more effective and enhance the healing potential."
References1 Johnson IT. 2004. New approaches to the role of diet in the prevention of cancers of the alimentary tract. Mutat Res.; 551(1-2):9-28; review
2 Svehlikova V, et al. 2004. Interactions between sulforaphane and apigenin in the induction of UGT1A1 and GSTA1 in CaCo-2 cells. Carcinogenesis; 25(9):1629-37
3 Sanjoaquin MA, et al. 2004. Nutrition, lifestyle and colorectal cancer incidence: a prospective investigation of 10998 vegetarians and non-vegetarians in the United Kingdom. Br J Cancer; 90(1):118-21
4 Block JB and Evans S. Fall 2000. Clinical evidence supporting cancer risk reduction with antioxidants and implications for diet and supplementation. JANA
5 Clark LC, et al. 1998. Decreased incidence of prostate cancer with selenium supplementation: results of a double-blind cancer prevention trial. Br J Urol.; 81(5):730-4
6 Wu K, et al. 2002. Calcium intake and risk of colon cancer in women and men. J Natl Cancer Inst; 94(6):437-46
7 Lund TD, et al. 2004. Equol is a novel anti-androgen that inhibits prostate growth and hormone feedback. Biol Reprod.; 70(4):1188-95
8 deVere White RW, et al. 2004. Effects of a genistein-rich extract on PSA levels in men with a history of prostate cancer. Urology; 63(2):259-63
9 Xu WH, et al. 2004. Soya food intake and risk of endometrial cancer among Chinese women in Shanghai: population based case-control study. BMJ; 328(7451):1285
10 Eliaz, I. Aug. 2004. Modified citrus pectin (MCP) in the treatment of cancer. Paper presented at The American Chemical Society Annual Meeting, Philadelphia