Whole Grains and Exercise Curb Risk for Colorectal Cancer

Roxanne Nelson, BSN, RN

September 07, 2017

Eating whole grains daily and ramping up activity levels can reduce the risk for colorectal/colon cancer, according to a new report from the American Institute for Cancer Research (AICR) and the World Cancer Research Fund (WCRF).

On the flipside, consuming red meat and processed meat increases the risk, as does drinking two or more alcoholic beverages per day.

The evidence was considered to be "strong" for all of these factors, in either enhancing or decreasing risk.

This is first time that research from AICR/WCRF has linked whole grains independently to lowering the risk for cancer.

There is a lot people can do to dramatically lower their risk. Dr Edward L. Giovannucci

"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, Boston, Massachusetts, in a statement. "The findings from this comprehensive report are robust and clear: Diet and lifestyle have a major role in colorectal cancer."

Continuous Update Project

The Continuous Update Project (CUP) analyzes cancer prevention and survival research that is associated with diet, nutrition, physical activity, and weight and is led and managed by WCRF International in partnership with the AICR and on behalf of World Cancer Research Fund UK, World Cancer Research Fund NL, and World Cancer  Research Fund HK. The findings from the CUP are used to update cancer prevention recommendations.

For the past decade, AICR/WCRF has published several reports on the effect of diet, nutrition, and/or physical activity on risk for several cancer types.

For example, as reported by Medscape Medical News, the group issued a report that provided evidence for a link between the risk for liver cancer and obesity and alcohol consumption. It also found that drinking coffee helped curb that risk.

A few years earlier, the group also reported  that physical activity, or the lack thereof, played a prominent role in the risk for endometrial cancer. Their report estimated that 59% of the cases of endometrial cancer (about 29,500 annually) could be prevented if women engaged in physical activity for at least 30 minutes per day and maintained a healthy body weight.

Key Findings for Colorectal Cancer

In the current report, the researchers looked at how diet, weight, and physical activity affected the risk for colorectal cancer. They analyzed 99 studies, which comprised more than  29 million adults and over 247,000 cases of colorectal cancer.

For factors that lowered the risk for disease, there was strong evidence (convincing) that being physically active decreases the risk for colon cancer (but no evidence for rectal cancer).

There was also strong evidence (probable) that consuming whole grains, food rich in dietary fiber, taking calcium supplements, and consuming dairy products decreased the risk for colorectal cancer.

In addition, limited evidence suggested that consuming foods containing vitamin C, eating fish, and taking a multivitamin and vitamin D could also reduce the risk.

In contrast, there was strong evidence that consuming red meat (probable) and processed meat (convincing) increases the risk for colorectal cancer.

This is not the first time that red and processed meat has been associated with a cancer risk. In 2015, the International Agency for Research on Cancer (IARC), the cancer agency of the World Health Organization, classified consumption of processed meat as "carcinogenic to humans." In addition, a study in premenopausal women  found that heavy consumption of red meat raised the risk for breast cancer.

The current report also found  strong evidence (convincing) that consuming approximately two or more alcoholic drinks per day, being overweight or obese, and being tall all heighten the risk for colorectal cancer.

Additionally, limited evidence suggests that low consumption of nonstarchy vegetables and fruit, and eating foods that contain hem-iron, might increase the risk for colorectal cancer.

The research continues to emerge for these factors, but it all points to the power of a plant-based diet, commented Alice Bender, MS, RDN, AICR director of nutrition programs, in a statement.

"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 Bender. "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."

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