If you're an American woman who typically eats a hamburger and fries for lunch, researchers predict that your colon cancer risk is significantly greater than that of your sister who prefers sushi.
A new study published Monday in the Archives of Internal Medicine found that a women who eat foods primarily from the so-called "Western diet" — high in red meats, sweets, desserts, french fries, and refined grains — have a 50 percent greater risk of colon cancer than those who consume few Western foods in their diet.
But there's hope for french fry lovers willing to reform. The study, led by Teresa Fung, a nutrition professor at Simmons College in Boston, also concluded that those who choose whole grains, fruits, vegetables and follow a more "prudent pattern" may be able to reduce the risk of colon cancer.
Previous studies have found associations between foods or nutrients and risk of colon and rectal cancer, but results have not always been consistent.
Dr. Amy L. Halverson, a colorectal surgeon at Northwestern Memorial Hospital in Chicago, said that the study's scope sets it apart from previous studies, which have also linked diet to colon cancer. She recommends a low-fat, high fiber diet to her patients.
"Hopefully this will prompt more physicians to educate their patients about the importance of diet in their overall health. I often devote a portion of my time with a patient to discuss the importance of a high fiber diet, and I think this is not the practice of most physicians," Halverson said.
Re-Examine Your Plate
The researchers used dietary information from more than 75,000 women who did not have a history of cancer and were between the ages 38 and 63. Two major dietary patterns were identified: "prudent" and "Western." Women classified as prudent eaters ate more fruit, vegetables, legumes, fish, poultry and whole grains, while their Western diet counterparts consumed more processed and red meats, sweets and desserts, french fries and refined grains.
During 12 years of follow up after the data collection, Fung and the other researchers identified 445 cases of colon cancer and 101 cases of rectal cancer. They observed a roughly 50 percent increase in risk for colon cancer in women ranked "most" Western eaters, vs. the mildest Western eaters. There were no associations between dietary patterns and rectal cancer.
Marilyn Tseng, an epidemiologist at the Fox Chase Cancer Center in Philadelphia, said the study was important because it doesn't just pinpoint single foods, like red meats as the culprit in increasing cancer risk. Instead, it suggests that people at risk should re-examine everything that goes on their plates.
"It's not just single nutrients or foods that are important, but rather combinations of foods, and whole scale dietary changes might be needed to have a greater effect on risk reduction — not the single factor changes that were previously advocated," Tseng said. "If people want to see a reduction in cancer risk through diet modification, it will probably have to come through a change in dietary pattern, not just single components in the diet."
The study was not terribly surprising, said Dr. Dennis J. Ahnen, a professor at the University of Colorado School of Medicine in Denver. Ahnen said there is abundant geographic data that countries with a Western diet have higher rates of colorectal cancer while high-fat diets may be associated with higher rates in both men and women.
"There is nothing unique about women in this regard — it just happens that there are only women in the cohort studied," Ahnen said. The study might not create sweeping changes, but it will bolster the advice that doctors already give, he said.
Even if Americans hear about the link between colon cancer and diet, doctors are not convinced that they'll become instant converts.
"This information should be followed up by efforts to teach individuals and their physicians about what foods are healthy and high in fiber," Halverson said. "Many foods that may seem healthy have hidden fat. Patients usually are not aware of what foods are actually the best sources of fiber."