TUESDAY, May 13, 2003 (HealthDayNews) -- High-calorie diets may actually protect you in a battle with colorectal cancer.
That's the surprising result of a new study from French scientists, who say that energy intake before a diagnosis of colorectal cancer predicts the odds of surviving the disease over time. Why eating more benefits these people isn't clear, however, and some experts aren't convinced the link is real. A recent study from the American Cancer Society found that being overweight or obese raises the risk of dying from any cancer, including colorectal tumors, by between 50 percent and 60 percent.
But study author Dr. Marie-Christine Boutron-Ruault believes people who eat more may develop a less aggressive form of colorectal tumors than do people whose diets are lower in calories. "We are going to follow up this idea by studying the genes of tumors" in patients with high and low energy intake, says Boutron-Ruault, a nutrition researcher at French Institute of Health and Medical Research in Paris.
Boutron-Ruault and her colleagues report their findings in the June issue of Gut. The researchers looked at 148 elderly men and women, whose average age was 64, who had undergone surgery to remove colorectal cancer. Subjects were asked to recall how much they ate before they were diagnosed with the disease.
The strongest predictor of a patient's risk of death over the 10 years after surgery was how advanced their disease was at the time of the operation.
Yet diet also appeared to play a role. People in the bottom two-thirds of daily energy intake were about 80 percent less likely to be living five years after surgery than those in the upper third of energy intake -- above roughly 3,000 calories a day for men and 2,300 calories a day for women. Although that amount of food is unusually high, especially for the elderly, not everyone in this group was obese, nor did being overweight seem to affect the results.
Since the study relied on people's memories of their diets, it used an imperfect measure of energy intake. What's more, the findings could simply be showing that people with less aggressive forms of colorectal cancer are able to eat more than those with deadlier tumors.
Martha Slattery, an epidemiologist who studies diet and cancer at the University of Utah School of Medicine in Salt Lake City, says the findings raise a "big red flag" in light of research linking obesity to a greater risk of developing colorectal cancer. "The two don't go together," says Slattery, who has looked at the issue.
What may explain the French results, she says, is if people who eat more are generally healthier than those who eat less. That could make them more prone to colorectal cancer, and presumably other tumors that become more likely with age.
In an unrelated study also published in Gut, Danish researchers say heavy drinking seems to raise the risk of rectal tumors, but not colon cancer. However, people whose tippling included at least 30 percent wine, while still at increased risk, cut their chances of rectal cancer significantly compared with beer and liquor drinkers.
More information
For more on colon cancer, visit the American Cancer Society or the National Cancer Institute.
