New research out today shows there’s strong evidence that what you eat and how much you move offer powerful protection against colorectal cancer. The report by AICR and the World Cancer Research Fund analyzed the global studies in the field, making it the most comprehensive evidence to date on how diet, nutrition, and physical activity link to colorectal cancer.
“Colorectal cancer is one of the most common cancers, yet this report demonstrates there is a lot people can do to dramatically lower their risk,” said Edward L. Giovannucci, MD, ScD, lead author of the report and professor of nutrition and epidemiology at the Harvard TH Chan School of Public Health.
All together, the report analyzed 99 studies, including data on 29 million people, of whom over a quarter of a million were diagnosed with colorectal cancer. Here are some of the key findings.
Lowering risk with whole grains and a walk
• Whole Grains – For the first time, AICR’s report showed that eating whole grains daily, such as brown rice or whole-wheat bread, reduces colorectal cancer risk, with the more you eat the lower the risk. Eating approximately three servings (90 grams) of whole grains daily reduces the risk of colorectal cancer by 17 percent.
• Being active – From walking to yard work, daily physical activity was found to protect against colon cancer. Previous AICR reports have found that regular physical activity also protects against breast and endometrial cancers.
Hot dogs, bacon and weight
• Red and processed meats – The report strengthened the link between hot dogs, bacon and other processed meats increasing the risk of colorectal cancer. For every 50 grams eaten every day -- about one hot dog – colorectal cancer risk increases 16 percent. Eating high amounts of beef, pork or other red meats (above 18 ounces cooked a week) also increases risk.
• Being overweight or obese – The evidence here is consistent with previous reports and other cancers. Excess body fat increases the risk of colorectal, along with 10 other cancers. Aside from not smoking, staying a healthy body weight is the single most important lifestyle step you can do to lower your cancer risk.
• Consuming two or more daily alcoholic drinks (30 grams of alcohol), such as wine or beer increases the risk. Alcohol is a recognized carcinogen, also linked to increased risk of other cancers, including breast and esophageal.
Fish, Fruits and Vegetables, Emerging Evidence
The report found other links between diet and colorectal cancer that were visible but not as clear. Evidence hinted that eating less than about a cup a day of fruit increases risk. The finding was the same for non-starchy vegetables.
For lowering risk, the report pointed to fish and foods containing vitamin C, but more research is needed here. Oranges, strawberries and spinach are all foods high in vitamin C.
As research continues to emerge for these factors, it all points to the power of a plant-based diet, says Alice Bender, MS, RDN, AICR Director of Nutrition Programs. “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.”
“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,” said Bender.