Obesity linked to colon cancer

By: Dr. Sunil Joseph, MD, Gastroenterologist

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Most people know that obesity is linked to heart disease, but did you know that it also increases the risk for colon cancer?

This is due to many factors, including:

  • Fat tissue produces excess amounts of estrogen, high levels of which have been associated with the risk of breast, endometrial, and some other cancers.
  • People who are obese often have increased levels of insulin and insulin-like growth factor-1 (IGF-1) in their blood, which may promote the development of certain tumors.
  • Obese people often have chronic low-level inflammation, which has been associated with increased cancer risk.

A Michigan State University study addressed this issue and reestablished the association between obesity and colon cancer.

The 18-month study followed 126 healthy, white asymptomatic males who underwent routine colonoscopies.

Approximately 78 percent of the men were obese or overweight based on their Body Mass Index (BMI) or waist circumference, and 30 percent were found to have colonic polyps. Obese patients were 6.5 times more likely to have three polyps compared to normal BMI patients.

Having a higher BMI is clearly associated with an increased risk for colon cancer, but distribution of the fat may have a role, as well. Belly fat is thought to increase the risk more so than generalized fat due to an associated increase in insulin resistance as described above.

How you can reduce your risk of colon cancer?

  • Achieve and maintain a healthy body weight.
  • Eat a well-balanced diet with plenty of fruits and vegetables. Limit your red meat and processed meat ingestion. Choose whole grain foods instead of refined grain foods, and limit sugar intake.
  • Participate in moderate exercise three to four times a week. Ideally, 20 to 30 minutes of cardiovascular exercise three to four times a week, but always consult your physician prior to starting an exercise routine.
  • Talk to your doctor about colon cancer screenings, and get the appropriate screening test for you performed at the recommended intervals.

The disease is one of the most preventable forms of cancer because it typically starts as a slow growing lesion in the colon called a polyp, which can be easily detected by screening tools such as a colonoscopy.

Multiple risk factors have been identified for colon cancer, including family history, personal history of inflammatory bowel disease, alcohol consumption, processed meat consumption, red meat consumption, smoking, and obesity.