Fitness plays a key role in battling cancer

August 06, 2007|Judy Foreman

So. You get the worst news of your life: cancer.

You dutifully sign on for chemo, surgery, radiation. You also vow to eat better. More fruits and veggies, less saturated fat -- all that good stuff should tip the odds in your favor, right?

There's actually surprisingly little evidence that such dietary changes prolong survival -- except perhaps for colon cancer.

What is crystal clear, though, is the importance of exercise and weight control. Gone is the folklore that people with cancer should avoid getting too thin. The real threat, say cancer nutritionists, is becoming or remaining overweight. At a basic metabolic level, excess weight and lack of exercise may not only add diabetes and heart disease to your cancer troubles, but can impair immune function and even boost levels of hormones, including insulin and estrogen, that may drive some tumors.

For cancer patients who had been hoping that a good diet might improve their survival odds, some disappointing news came out this summer when scientists from the University of California at San Diego reported the long-awaited results from the Women's Healthy Eating and Living study. This randomized, controlled trial followed more than 3,000 women who had been treated for early stage breast cancer. After an average of 7.3 years of follow-up, the researchers found that women randomly assigned to the federally recommended "five-a-day" diet with five servings of fruits and vegetables, fared no worse than those who ate at least eight servings of fruits and vegetables, plus vegetable juice, a lot of fiber, and very low fat (15 to 20 percent of calories).

Somewhat better news was released in December in the Women's Intervention Nutrition Study, led by Dr. Rowan T. Chlebowski, a medical oncologist at the Los Angeles Biomedical Research Institute. The team studied 2,400 women who had been treated for early-stage breast cancer and randomly assigned them to a dietary fat reduction group or regular diet group. After five years of follow-up, there were significantly fewer recurrences among members of the lower fat group, most of whom lost weight.

The trouble is, said Chlebowski, it's not clear whether it was the low fat diet per se or losing weight that conferred the benefit. And cues from other research suggest that losing weight, in part because it brings insulin levels into better control, may be the key.