Vegetarian Diet May Lower Colon Cancer Risk
By Steven Reinberg
For fish-eating vegetarians, the protective link was even stronger, researchers said.
Colorectal cancer is the second leading cause of cancer death in the United States. Screening efforts, including colonoscopy, have helped save many lives by detecting precancerous polyps, said the study’s lead researcher, Dr. Michael Orlich.
“However, it is even better to prevent cancers from forming in the first place. We call this primary prevention,” said Orlich, who is an assistant professor of preventive medicine at Loma Linda University in California. “Diet is a potentially important approach to reduce the risk of developing colorectal cancer.”
The new study, which involved more than 77,000 adults, found that people consuming healthy vegetarian diets may have a lower risk of colon and rectal cancers than non-vegetarians, Orlich said.
“Our vegetarians not only ate less meat than the non-vegetarians, but also less sweets, snack foods, refined grains and caloric beverages,” he said. And they ate more fruits, vegetables, whole grains, beans and nuts, he added.
Prior evidence has linked eating red and processed meats to a higher risk of colorectal cancer, and consuming fiber-rich foods to a lower risk, Orlich said.
Nevertheless, Dr. Alfred Neugut, professor of epidemiology at Columbia University Medical Center in New York City, said no one has identified with certainty why a vegetarian diet would reduce the risk for colon cancer.
It’s not known whether there is something in vegetables that is protective or whether something in meat is harmful, he said.
Dietary studies can only show an association between cancer and diet, not a cause-and-effect relationship, Neugut said. “That’s the problem in dietary studies of cancer. We don’t know exactly what the connection is,” he said.
Neugut said that a vegetarian diet might be a sign of other healthy behaviors, such as exercising and not smoking, which could also reduce the risk for cancer.
Orlich’s research, published in the March 9 online edition of JAMA Internal Medicine, included data on nearly 77,700 men and women enrolled in the Adventist Health Study 2. After seven years of follow-up, 380 cases of colon cancer and 110 cases of rectal cancer were identified.