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Dietary / Exercise Recommendations for Colon Cancer

Dietary and Exercise Recommendations Regarding Colon and Rectal Cancer

Richard L. Whelan, MD, Chief of Colon and Rectal Surgery, C.C.C.N.Y., St. Luke’s Roosevelt Hospital

Researchers and physicians have long suspected a link between diet and lifestyle and the development of Colon and Rectal Cancer (CRC). For example, dietary fiber has been thought to be protective whereas red meat is thought to promote cancer development. Despite some suggestive evidence, it has proven very difficult to obtain the data needed to firmly verify these suspicions.* The World Cancer Research Fund/ American Institute for Cancer Research Continuous Update Project (WCRF/AICR CUP) continually tracks the published evidence regarding a number of different types of cancer. In recent years they have released a series of recommendations and guidelines for each cancer type based on the available data. When their experts believe there is sufficient evidence regarding a number of dietary items or lifestyle behaviors they release an updated report which incorporates these changes. This past spring the WCRF/AICR CUP updated their findings and guidelines for CRC. Their recommendations, which follow, are based on a review of 1,012 published studies.

For years, there has been “convincing” evidence that regular intake of red meat (beef, pork, or lamb) and processed meat (ham, bacon, pastrami, salami, hot dogs, sausage) promote the development of CRC. These new guidelines are unique in that they correlate the amount of meat eaten daily, on average, with the risk of developing CRC. Daily intake of 2.5 ounces of red meat per day (about 18 ounces/week) minimally increases CRC risk. Intake of 3.5 ounces of red meat/day (24.5 ounces/week), however, increased by 17 % the chance of a person developing a large bowel cancer. Daily intake of 7 ounces of red meat per day (49 ounces/week) increases by 34 % the risk of CRC. Processed meat carries an even higher risk; daily intake of 3.5 ounces/day increases CRC risk by over 36 %. Intake of 7 ounces per day increases risk by 72 %.

The Panel also concluded that, for men, there is convincing evidence that regular alcohol intake increases the risk of CRC. For women, alcohol “probably” increases CRC risk.

In the last report (2007) from this Panel the conclusion regarding fiber was that it was probably protective. In the interim a number of additional studies regarding fiber have been published. The current report states that there is now “convincing” evidence that food containing dietary fiber (vegetables, fruits, beans and whole grains) is protective against CRC.

The report also found that Garlic was “probably” protective against CRC. The review Panel concluded that milk probably reduces the risk of CRC. There is also evidence that calcium containing supplements also probably reduces the risk of CRC. The Panel advised regular intake of milk rather than calcium containing supplements because they prefer whole foods to supplements, in general.

Excess body fat and abdominal fatness are also risk factors for CRC according to this latest report. On the contrary, regular exercise and physical activity are believed to be protective against CRC.

(*Ideally, large prospective studies would be done that would observe and follow, for years, groups of thousands of patients with different diets or lifestyles and then determine the rate of cancer development in each group. Such studies are very expensive and not practical. Instead, most of the evidence regarding diet and lifestyle comes from epidemiologic studies which are less conclusive.)