Colorectal Cancer

Worldwide, colorectal cancer is the second leading cause of cancer-related death. It accounts for 10% of cancer deaths in the United States, and studies show that rates are rising among young people. Adults born around 1990 have twice the risk of colon cancer and four times the risk of rectal cancer compared with adults born around 1950, according to a study published by the National Cancer Institute. But there are steps you can take to significantly reduce your risk, including choosing healthful, plant-based foods. Evidence suggests that dietary habits may influence both colorectal cancer incidence and progression:

Choosing High-Fiber Foods

Fiber has been linked to a reduced risk for colorectal cancer. Fiber, which is found only in plants, is abundant in fruits, vegetables, whole grains, and legumes. Studies of both total fiber intake, as well as high-fiber foods individually (fruits and vegetables, whole grains, legumes, and nuts), have all revealed protection against colorectal cancers. One study of nearly 200,000 people found a nearly 40% lower risk for colorectal cancer in men who ate more than 35 grams of fiber per day, compared with those who ate roughly 13 grams per day. A meta-analysis found a 12% lower risk for colorectal cancer in those who ate the most total dietary fiber, and consumption of three servings per day of whole grains was also associated with a 17% lower risk. Another meta-analysis found that those who eat the most fruits and vegetables reduced their risk by approximately 10%, compared with those who ate the least. Legumes and nuts have also been associated with a reduced risk.

Avoiding Red and Processed Meat

The World Health Organization has determined that processed meat is a major contributor to colorectal cancer, classifying it as “carcinogenic to humans.” Just one hot dog or a few strips of bacon consumed daily increases cancer risk by 18%. The World Health Organization also found that 100 grams of red meat per day increases the risk for colorectal cancer by 17%.

The association between meat and colorectal cancer risk has been explained by the presence of carcinogenic compounds including nitrosamines, polycyclic aromatic hydrocarbons, and heterocyclic amines (carcinogens formed as a result of high-temperature cooking) and by the pro-oxidant effects of heme iron. Foods high in saturated fat and cholesterol, higher serum cholesterol and triglycerides, and higher levels of oxidized LDL are also associated with greater colorectal cancer risk.

Maintaining a Healthy Weight

A number of studies have found a link between excess weight and death from colorectal cancer. Individuals with a BMI of 40 or greater have a roughly 45% greater risk for colorectal cancer, compared with those who are at a healthy weight (BMI 18.5-24.9). Individuals who are mildly or moderately obese appear to have a 10% and approximately 35% greater risk, respectively. One meta-analysis concluded that for every 5 kilograms of weight gained during adulthood, the risk for colorectal cancer increased by 4%. For a weight gain of roughly 30 pounds, the risk increased by 22%, compared with individuals who had maintained their previous weight. Learn more about how a plant-based diet can help maintain a healthy weight. Studies have also found that exercise may decrease the risk for colorectal cancer.

Screening

Regular screenings and timely removal of precancerous lesions are key. American Cancer Society guidelines now recommend that screening begin at age 45. Be sure to work with your health care provider to find the best screening options for you.