The link between carbohydrates and colon cancer is not fully understood. Fiber, a type of carb, might have important protective effects. In addition, eating "bad" carbs, such as added sugars in processed foods and soft drinks, might increase your risk of colon cancer. Moreover, in addition, eating too few fruits and vegetables, major carbohydrate sources, is associated with a higher risk. What is known is that beyond genetic and health conditions that increase your risk for colon cancer, some risk factors are completely under your control. These include your weight, smoking, alcohol consumption and your diet.
Carb Facts
Carbs are a major macronutrient. That means, like fat and protein, your body needs fairly large amounts of carbs each day to carry out important biological processes. Carbs are the preferred fuel source, meaning your body is most efficient at taking energy to your cells from carb food sources. Moreover, it's the only fuel source that can cross the blood-brain barrier into your brain. They protect your muscles from being used as a fuel source, so they're tied to weight control and bone health. In addition, carbs provide important nutrients, including vitamins, minerals and fiber, to aid in digestion, gut health and cholesterol control. You're probably most familiar with the role of carbs with diseases such as diabetes, but carbs, especially fiber, also play a role in protecting you from other diseases, one of which might be colon cancer.
Colon Cancer Facts
Colon cancer can begin in your colon or your rectum. The average adult colon spans 5 feet long and makes up most of the large intestine. As part of your digestive system, its job is to draw water and salts from the foods you eat and send out waste through your anus. The end of the colon is the rectum, where your stools are stored until you have a bowel movement. Colon cancer starts within the inner layer of the colon and can grow outward through all the layers. The stage of cancer is based primarily on how many layers of your colon are affected by the disease. In most cases, colon cancer starts as a polyp, or a growth of tissue, and progresses slowly over many years. Catching and removing the polyp early might help prevent the start of cancer. Like other cancers, colorectal cancer can also involve the growth of tumors in this area, but this is rarer, according to the American Cancer Society; 95 percent of colon cancer cases are from a type of polyp known as an adenoma.
Incidence of Colorectal Cancer
In 2007, 142,672 people in the United States had a new diagnosis of colon cancer, and 53,219 succumbed to the disease. The Centers for Disease Control and Prevention, or CDC, reports that colon cancer is the second leading cancer killer among all cancers that affect both women and men. African Americans have the highest rates of incidence and death from colon cancer. Whites rank second highest in both statistics. Likewise, men as a group get and die from colon cancer at a higher rate than women.
Carbs and Risk Factors for Colon Cancer
The growth of polyps, along with bowel diseases and other genetic factors, play a big role in your risk for colon cancer, but so do lifestyle factors, which bear on your intake of carbs. For example, eating too few fruits and vegetables, consuming a low-fiber and high-fat diet, and being overweight or obese contribute to your risk. Medical science hasn't completely figured out how carbs, especially fiber, interact with your risk, and results are highly conflicting. For example, the American Cancer Society says diets high in fruits and vegetables are linked with lower risk, but that high-fiber diets "don't seem to help." In Elmhurst College's "Virtual Chembook," Charles Ophardt writes, fiber has a protective effect, and populations of people known to eat high-fiber diets have a lower incidence of colon cancer. However, people who suffer constipation --- possibly from too little fiber --- don't have higher rates of colon cancer than people who are regular. Jane Higdon of Oregon State University's Linus Pauling Institute suggested that the conflicting reports about the protective mechanism in fiber might be related to the type of fiber consumed and how much fat is in your diet. She wrote that the largest study to date, the European Prospective Investigation into Cancer and Nutrition, said fiber from foods definitely protects against colon cancer development.
Type Matters
Research appearing in the journal "Cancer Epidemiology, Biomarkers and Prevention," sheds more light on the role of carbs in colon cancer. Researchers from Harvard Medical School investigated 1,809 cases of colorectal cancer and examined the impact of carb intake, glycemic load and glycemic index, as well as the type of carbs consumed. Men and women had different results. The researchers observed a 27 to 37 percent increase in risk of colon cancer with increased carb intake, as well as with increased sucrose and fructose intake. Sucrose is most commonly consumed as table sugar, and fructose is both a naturally occurring sugar in fruits and honey, and an added sugar most well-known in high-fructose corn syrup. These results did not hold up completely for women. Only women who were overweight and had low levels of physical activity showed a greater risk, but factors such as fructose and sucrose didn't make much of a difference.
References
- American Cancer Society: Colorectal Cancer
- National Digestive Diseases Information Clearinghouse: Anatomic Problems of the Colon
- CDC: Colorectal (Colon) Cancer
- Elmhurst College Virtual Chembook: Cellulose
- Linus Pauling Institute: Fiber
- "Cancer Epidemiology, Biomarkers and Prevention"; Dominique Michaud et al; January 2005
