Researchers Warn That Obesity Is Risk Factor for Colorectal Cancer

Researchers at the American Institute for Cancer Research (AICR) warn that obesity appears to be a risk factor for developing colorectal cancer, and the nation's current obesity epidemic may see cancer rates rise rapidly in the coming years.

After conducting a thorough review of existing scientific literature on the obesity-cancer link, researchers found a growing number of studies showing that obesity is definitely a factor in some of the most common forms of cancer.

Many of the first studies on the link between obesity and colorectal cancer focused on caloric intake, showing that diets high in calories and fat are associated with a higher cancer risk. More recently, however, investigators have looked at the importance of maintaining an energy balance, where the number of calories taken in is more or less equal to the number of calories burned, in fighting colorectal cancer.

Consuming excess calories causes the body to hang on to dietary and environmental carcinogens rather than eliminating them, trapping them in the body's fat stores. Excess fat, resulting in insulin resistance, also stimulates colon cells to reproduce rapidly and increases the risk of developing colorectal cancer.

This effect is more commonly seen in men as they tend to store fat around the abdomen, and abdominal fat has been shown to secrete insulin at high levels.

Regular physical activity has been strongly linked with a reduced risk of colorectal cancer, and researchers concur that exercising regularly may offer significant protection against the disease. Researchers speculate that exercise prevents the buildup of fat tissue and regulates the levels of insulin and other hormones in the blood.

Physical activity may also speed the passage of dietary and environmental carcinogens from the body and reduce the time these substances spend in contact with colorectal tissues.

AICR researchers recommend that people limit their weight gain during adulthood to no more than 11 pounds, get 1 hour of moderate exercise each day and one hour of vigorous exercise each week, and eat a diet high in vegetables, fruits, whole grains, and beans.

Other Sources: American Institute for Cancer Research