What Veggies Might Do for Your Cancer Risk

Colorectal cancer rates were lower among vegetarians

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) The wisdom of the common parental advice to eat your veggies doesn't just apply to children.

Vegetarians and those who eat veggie-heavy diets may be less likely to develop colorectal cancer than meat-eaters, a new study found.

“The evidence that vegetarian diets similar to those of our study participants may be associated with a reduced risk of colorectal cancer, along with prior evidence of the potential reduced risk of obesity, hypertension, diabetes and mortality, should be considered carefully in making dietary choices and in giving dietary guidance,” wrote the authors of this study, led by Michael J. Orlich, MD, of Loma Linda University in California.

Edward Giovannucci, MD, ScD, a professor of nutrition and epidemiology at the Harvard School of Public Health, told dailyRx News that he didn't find the results of this study surprising.

"Red and especially processed red meats have been associated with elevated risk of colorectal cancer and simply by avoiding these may be beneficial against colorectal cancer," he said. "Secondly, although the evidence is not definitive, there are indications that eating more plant foods may provide beneficial nutrients including folate, calcium and fiber.

"A vegan diet may be beneficial but interestingly in this study fish seemed to lower risk beyond a vegetarian diet. Fish contains omega-3 fatty acids, which may be anti-inflammatory, and fish is one of the few natural dietary sources of vitamin D, which has been linked to lower colorectal cancer risk."

Past research has had mixed results when it comes to the risk of colorectal cancer among people who do not eat meat, Dr. Orlich and team noted.

These researchers looked at nearly 78,000 people who were Seventh Day Adventists — a Protestant Christian denomination that recommends vegetarianism. Those who took part in this study answered questions about eating in terms of how often and how much they ate of more than 200 foods.

Dr. Orlich and colleagues looked at cancer registries and sent out surveys every two years, asking people in the study if they had been told they had cancer.

Of those in the study, 380 developed colon cancer and 110 developed rectal cancer in the average 7.2 years of follow-up.

People who were vegetarian had a 22 percent lower risk for colorectal cancer than those who ate meat. They had a 19 percent lower risk for colon cancer and 29 percent lower risk for rectal cancer than meat-eaters.

Dr. Orlich and team also found that people who ate vegetables and fish but no other meats were those with the least colorectal cancer. People in this group, called pescovegetarians, had a 43 percent lower risk for colorectal cancer compared to people who ate meat.

Colorectal cancer is the second deadliest cancer among men and women in the US, according to the American Cancer Society.

People who mainly eat vegetables tend to exercise more and smoke less than people who eat meat, Dr. Orlich and team said. Vegetarians also tend to weigh less and eat more fiber.

This study was published online March 9 in JAMA Internal Medicine.

Grants from the National Cancer Institute and World Cancer Research Fund funded this research. Dr. Orlich received past funding from the Seventh Day Adventist Church for travel and speaking.

Review Date: 
March 8, 2015
Last Updated:
March 10, 2015