As reported on CBS News, March 15, 2007.

Diet, Exercise May Lower Colon Cancer Risk

Some Studies Have Shown Exercise Can Reduce Risk of Colon Cancer By Half

(CBS) Fifty-nine-year-old John Knudson is a former couch potato. He laced up his jogging shoes shortly after his first colonoscopy, CBS News correspondent Kelly Wallace reports.

"When I was in there, my doctor said, 'Wow, you're a regular polyp farm, aren't you,'" Knudson says.

He decided to participate in an experiment examining the impact of exercise on colon cancer risk, run by Dr. Anne McTiernan of the Fred Hutchinson Cancer Research Center in Seattle.

After volunteers like Knudson exercised at least four hours a week for a year, McTiernan noticed a difference. Dark, abnormal looking cells that could become polyps and even colon cancer, turned into more normal-looking areas.

"We were able to see that the rate of growth of these cells was reduced with exercise," McTiernan says.

Some studies have shown exercise can reduce the risk of colon cancer by half.

Susan Tourtillotte is hoping diet can make a difference, too.

She lost her father to colon cancer four years ago. "After it is over, that's when the most frightening part sets in because then you start looking into your medical past and seeing the skeletons in the closet," she says.

Tourtillotte grew up eating red meat; she wants her sons growing up on fish, fruit and vegetables.

She's enrolled in a colon cancer program run by Dr. Joel Levine of the Colon Cancer Prevention Program at the University of Connecticut Health Center.

"Don't eat a whole lot of red meat," Levine says. "Eat dairy products, but not too much. Get your calcium up at the right level, get enough sunlight and vitamin D and eat your vegetables."

He says vegetables — like broccoli, Brussels sprouts, cauliflower and cabbage — may trigger a chemical process that turns on an important gene which suppresses tumors. More research is necessary to prove a direct link.

Tourtillotte has all the facts she needs.

"I really feel I am going to set a different course, and I think that's what my Dad would want," she says.

She'll do anything she can to protect her family.