Diet and Lifestyle Plays Major Role in Colorectal Cancer Risk

Physical activity and a whole grain-rich diet lowers colorectal cancer risk, whereas red meat increases the risk.

A balanced diet rich in whole grains may lower an individual’s risk for colorectal cancer, whereas high consumption of red meat, processed meat, and alcohol can increase the risk.

The new report by the American Institute for Cancer Research (AICR) and the World Cancer Research Fund is the first to independently link whole grains to a reduced cancer risk.

The report evaluated scientific research worldwide on the effects of diet, weight, and physical activity on colorectal cancer. The 99 studies included data from 29 million individuals, of whom more than one-quarter of a million were diagnosed with colorectal cancer.

Consuming more than 500 grams of cooked red meat per week was found to increase the risk of colorectal cancer, as well as being overweight/obese and consuming 2 or more alcoholic beverages daily.

The findings also showed that consuming approximately 3 servings of whole grains per day reduced the risk of colorectal cancer by 17%, building on prior research indicating foods rich in fiber decreases the risk of cancer.

Individuals who are physically active have a lower risk of colon cancer compared with individuals who engage in little to no physical active. The authors noted the decreased risk was observed for colon cancer but not rectal cancer.

“Colorectal cancer is one of the most common cancers, yet this report demonstrates there is a lot [of] people can do to dramatically lower their risk,” said lead author Edward L. Giovannucci, MD, ScD. “The findings from this comprehensive report are robust and clear: Diet and lifestyle have a major role in colorectal cancer.”

In the United States, colorectal cancer is the third most common cancer among men and women. According to AICR, 47% of cases could be prevented each year with lifestyle changes.

“Many of the ways to help prevent colorectal cancer are important for overall health,” Giovannucci said. “Factors such as maintain a lean body weight, proper exercise, limiting red and processed meats, and eating more whole grains and fiber would lower risk substantially. Moreover, limiting alcohol to at most 2 drinks per day and avoidance or cessation of smoking also lowers risk.”

Other links between diet and colorectal cancer were also observed, including limited evidence that risk increases with low intake of non-starchy vegetables and fruit, and higher risk observed for intakes of less than 100 grams per day of each.

Associations were also observed between consuming fish and foods containing vitamin C and a lowered risk of colorectal cancer.

More research needs to be done, but these factors show promise, the authors noted.

“Replacing some of your refined grains with whole grains and eating mostly plant foods, such as fruits, vegetables, and beans, will give you a diet packed with cancer-protective compounds and help you manage your weight, which is so important to lower risk,” said Alice Bender, MS, RDN, AICR director of Nutrition Programs. “When it comes to cancer there are no guarantees, but it’s clear now there are choices you can make and steps you can take to lower your risk of colorectal and other cancers.”