High Meat Consumption Linked to Heightened Cancer Risk

"Our findings for colorectal cancer are consistent with the recommendations from the recently published World Cancer Research Fund and American Institute for Cancer Research to limit consumption of red meats, such as beef, pork and lamb," said Cross. "Our study also suggests that individuals consuming high quantities of red meat may be at an elevated risk for esophageal, liver and lung cancer."

There are several possible routes by which red and processed meats may contribute to cancer, the NCI researchers said. Meats are a source of saturated fat and iron, both of which have been linked to cancer, and also the source of several compounds that are known to affect cell development, they added.

Cooking at high temperatures might also contribute to cancer risk, Cross added.

"Heterocyclic amines and polycyclic aromatic hydrocarbons are formed when meats are cooked well-done by high temperature cooking methods, such as barbecuing," she said.

The study, published in the December 2007 issue of the online journalPLoS Medicine, brought a mixed response from experts in the field.

"This adds to the body of knowledge that supports recommendations that to reduce the risk of colon cancer, you should reduce your consumption of red and processed meats," said Colleen Doyle, director of nutrition and physical activity for the American Cancer Society. "It also adds to the smaller amount of research tying red and processed meats to other types of cancer risk. The American Cancer Society recommends reducing red and processed meat consumption to reduce the risk of prostate cancer."

"We really see this study that it further illustrates the complexity and challenges of understanding research related to diet and cancer. They also could have said red meat is protective of endometrial cancer. The challenges of looking at diet and cancer are just vast," said Mary K. Young, vice president for nutrition with the National Cattlemen's Beef Association. She noted that the researchers did not ask how food was prepared, which she said could have affected the health outcomes.

Doyle and Young, both dietitians, agreed that diet can play a critical role in health.

"One of the most important things people can do to lower their risk of chronic disease, including cancer, is maintain a healthy weight," added Young, who recommended that people follow national dietary guidelines, watch their serving sizes and stay physically active.

People worrying about cancer and diet should take a balanced approach, said Doyle. " No one food is going to put our cancer risk over the top. If you are someone who eats steak or pork or lamb or salami or hot dogs, etc., on a regular basis and/or in large portion sizes, I would probably suggest you look for healthier protein sources to include in your diet," she added. The American Cancer Society recommends that people eat lots of fruits, vegetables and whole grains with some lean proteins to prevent cancer.

Research released last summer in the eJournal of the National Cancer Institutesuggested that choline, found in many red meat and dairy products, may contribute to the growth of polyps that lead to colon cancer.

And another study, released in the Aug. 17Journal of the American Medical Association, showed that colon cancer patients who eat a diet rich in fruits, vegetables, poultry and fish can significantly lower the risk of their cancer returning. In contrast, those patients whose self-reported diet included high intakes of meat, fat, refined grains and dessert were more than three times more likely to see their colon cancer return.

"If I were a cancer survivor," Doyle said, the new research "would make me stand up and take notice."

More information

To learn more about how diet and physical activity choices can help prevent cancer visit the American Cancer Society's Food and Fitness guide.

SOURCES: Mary K. Young, M.S., R.D., vice president of nutrition, National Cattlemen's Beef Association; Colleen Doyle, M.S., R.D., director, Nutrition and Physical Activity, American Cancer Society; Amanda J. Cross, Ph.D., Nutritional Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute; December 2007,PLoS Medicine