Eating a vegetarian diet has been associated with a lower risk of colorectal cancer compared with non-vegetarians in a study of Seventh-Day Adventist men and women, according to an article published online by JAMA Internal Medicine.
Dietary factors have been identified as a modifiable risk factor for colorectal cancer, including red meat which is linked to increased risk and food rich in dietary fiber which is linked to reduced risk, according to the study background. Red meat may also contribute to colon cancer by virtue of its high iron content. Both high dietary iron and high serum (blood) iron have been associated with increased risk to colon cancer. Iron and fat both decrease manganese superoxide dismutase (SOD) activity in the cells lining the colon. Manganese SOD has tumor suppressive activity and has been found lacking in most colon tumors.
Low-fiber diets have also been associated with increased risk of colorectal cancer. The National Cancer Institute recommends a high-fiber diet that includes at least 5 servings of fruits and vegetables each day. To increase the amount of fiber in your diet, eat more vegetables, fruits, and whole-grain breads and cereals.
Among 77,659 study participants in the study, Michael J. Orlich, M.D., Ph.D., of Loma Linda University, California, and coauthors identified 380 cases of colon cancer and 110 cases of rectal cancer. Compared with nonvegetarians, vegetarians had a 22 percent lower risk for all colorectal cancers, 19 percent lower risk for colon cancer and 29 percent lower risk for rectal cancer. Compared with non-vegetarians, vegans had a 16 percent lower risk of colorectal cancer, 18 percent less for lacto-ovo (eat milk and eggs) vegetarians, 43 percent less in pesco-vegetarians (eat fish) and 8 percent less in semi-vegetarians, according to study results.
A Vegetarian Diet
Vegetarian eating patterns are defined as those that exclude all meats (beef, pork, lamb, poultry, fish, etc). Some vegetarians also exclude eggs but not dairy products, lacto vegetarians, some exclude dairy products but not eggs, ovo vegetarians, and some exclude all foods from animal sources (all meats, dairy, eggs, and other animal derived foods including gelatin, honey, casein, lactose, etc), vegans.
Vegetarian diet: an Advantage over Colorectal CancerDiets rich in plant foods decrease the risk of many types of cancer; specifically, beneficial effects have been shown for fiber, fruits, vegetables, legumes including soy foods, and whole grains. Intake of legumes is negatively associated with risk of colon cancer.
Specific constituents in whole foods such as soluble fiber, carotenoids, indoles, isoflavones, among hundreds of others have been linked to protection against specific cancers. Vegetarian and vegan diets tend to be higher in these protective plant foods and plant constituents than omnivorous diets. Vegetarian and other diets built mainly from plant foods would also be expected to support higher immune function, largely because they tend to be richer in cancer protective phyto-chemicals.
Protective elements in a cancer-preventive diet include selenium, folic acid, vitamin B12, vitamin D, chlorophyll and antioxidants such as carotenoids (alpha-carotene, beta-carotene, lycopene, lutein, cryptoxanthin). Make sure your diet contains these nutrients.
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