- 3 out of 10 colon cancer deaths can be attributed to dietary factors.
- There is convincing evidence that foods rich in dietary fiber help reduce the risk of colorectal cancer.
- Those with a family history of colon cancer should begin screening before the age of 50, as they are at greater risk of the disease than the average person.
Colorectal cancer has been classified as one of the three most common cancers in the world, including in Thailand. Over the past decades, researchers have tried to link food causes to the risk of colon cancer. Researchers have suggested that 3 out of 10 colon cancer deaths are likely attributed to dietary factors.
Various studies as well as data published by the World Cancer Research Fund International have summarized the dietary factors that could reduce the risk of colorectal cancer as follows:
1. Foods in the Convincing Group
- Consumption of foods containing dietary fiber, such as fruits and vegetables, were shown to reduce the risk of colorectal cancer by 10% per 10 grams of fiber per day. This is because fiber increases stool weight, helps reduce carcinogens in the colon, reduces the amount of fat and bacteria in the colon and converts dietary fiber into short-chain fatty acids with anti-cancer properties.
- Various whole grains, classified as foods containing dietary fiber, showed a 21% lower risk per three servings per day for colorectal cancer and a 16% lower risk for colon cancer due to antioxidant mechanisms and natural fibers which help dilute toxins in the colon.
2. Foods in the Probable Group
- Dietary calcium showed an 8% decreased risk per 300 milligrams per day. An analysis of a large group of people followed for 6 up to 16 years found that those who consumed high calcium foods like milk, soybeans, sesame seeds, green leafy vegetables and dried fish showed a reduced risk of colon cancer by up to 14%. The mechanisms that likely reduce the risk are calcium binding to free fatty acids and bile acids, inhibiting cancer cell division and promoting cell apoptosis, which refers the death of self-destruction of cells so that they don’t change into cancer cells.
- Consumption of cow’s milk and grain milks showed a 9% decreased risk for colorectal cancer per 2 liter of milk per day, and showed the greatest results for those drinking between 0.5-0.8 liters of milk per day, with a reduced risk of up to 15%.
- Garlic was shown to reduce the risk by 3-4% when the a recommended amount of 100 grams per day was consumed. It is expected that the risk reduction occurs due to the antioxidant properties of garlic which reduce mutations and oxidative stress in intestinal cells.
3. Foods in the Limited-Suggestive Group
- Non-starchy vegetables, such as cabbage, broccoli, carrots, tomatoes, bell peppers and lettuces, can reduce the risk by 2% per 100 grams per day. Of special interest are vegetables in the cruciferous group, such as broccoli, which may decrease the risk by up to 16%. The mechanism likely to aid in risk reduction is the presence of folate, vitamins, dietary fibers, mineral salt, flavonoids and glucosinolates, which have anti-cancer properties.
- Foods high in vitamin D, such as mushroom, egg, fish, cheese and cod liver oil, showed a 5% decreased risk per international unit (IU) per day. The mechanism likely to reduce the risk is the presence of properties promoting the anti-proliferation of cancer cells and the stimulation of the body’s immune system.
- https://www.pharmacy.mahidol.ac.th/th/knowledge/article/289/ Associate Professor Wimol Srisuk, Department of Food Chemistry, Faculty of Pharmacy, Mahidol University
- Song M, Garrett WS, Chan AT. Nutrients, foods, and colorectal cancer prevention. Gastroenterol 2015; 148:1244-60.
- World Cancer Research Fund, American Institute for Cancer Research. Continuous Update Project. Colorectal Cancer 2011 Report. Food, Nutrition, Physical Activity, and the Prevention of Colorectal Cancer.