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• By Maureen Williams, ND

Exercise Works Early to Prevent Cancer

Experts agree that exercise plays an important role in preventing cancers, including colon cancer. But how early in the development of colon cancer does its anticancer effect begin? Very early, according to the British Journal of Cancer. A report confirms that people who exercise have a lower risk of precancerous colon polyps.

How early in colon cancer development does exercise's effect begin? Very early, according to the British Journal of Cancer

The numbers tell the story

The report is based on a meta-analysis of the research: Data from 20 previous studies examining the relationship between physical activity and precancerous colon polyps, know as colon adenomas, was included in the analysis. The authors of the report concluded:

• People who engage in the most physical activity have a 16% lower risk of colon adenomas compared to the least active people.
• Physical activity is especially effective against large and advanced colon adenomas: exercisers have a 35% lower risk of developing these most dangerous types of polyps.

“Our meta-analysis, combined with studies demonstrating physical activity’s role in colon cancer prevention, suggests that physical activity has a role across the carcinogenic process,” said lead study author Dr. Kathleen Wolin of the Washington University School of Medicine in St. Louis, Missouri. “The anticancer effect of physical activity may be related to enhanced immune function, decreased inflammation, and lower insulin levels and insulin resistance."

Take steps to prevent cancer at its earliest stage

Not everyone with colon polyps will develop colon cancer. Benign polyps are made up of cells that won’t become cancer, while colon adenomas have abnormal cells that can become cancer. If colon adenomas are found and removed early, the journey to cancer can be interrupted, but this type of polyp often comes back. Preventing precancerous colon polyps is a top priority for preventing colon cancer. Here are some prevention strategies:

• Exercise. Set a goal of four hours of moderate-intensity exercise per week—spread out over the week, that’s about 35 minutes per day.
• Eat a low-fat, high-fiber diet. Aim for 18 grams of fiber and 20% or fewer of each day’s calories from fat. This type of diet has been associated with a lower incidence of colon adenomas even in people with high risk because they’ve had them before.
• Fill up on fruits and vegetables. The overwhelming consensus is that five or more servings per day are necessary for good health, including colon polyp and cancer prevention.
• Take a daily multivitamin. Several studies have found that multivitamin users have a lower risk of colon cancer.
• Consider a calcium supplement balanced with magnesium. Researchers have found that calcium supplementation provides lasting prevention against colon adenomas.
• Get plenty of vitamin D. Low vitamin D levels have been linked to increased risk of colon polyps and cancer. A combination of a little sunlight, plenty of fortified foods, and a vitamin D supplement will provide all you need.

(Br J Cancer 2011;104:882–5)