Red Meat Diet Linked to Esophageal and Gastric Cancer

Summary
A recent study investigated whether red and processed meats could increase the risk of cancer through several potential mechanisms. It was found that the intake of red meat was associated with a type of esophageal cancer (cancer of the gullet). Meat cooked at high temperature causes the formation of certain chemicals that are potent cancer causatives and it was shown that excess intake of such chemicals was associated with stomach cancer. This study was done because, according to the researchers, “Although there have been multiple studies of meat and colorectal cancer, other gastrointestinal malignancies are understudied.”

Introduction
The association of colon cancer with consumption of red meat has been well established. However, consuming red meat could also cause various other cancers of the digestive system. Esophageal cancer is the sixth leading cause of cancer mortality worldwide and gastric cancer is the second. Certain ways of cooking meat can lead to the creation of cancer-causing agents. Meat is a rich source of iron and processed meat is a source of nitrates and nitrites, all of which have compounds that have been shown to cause cancer. This study was done to assess the effect of meat specifically on esophageal and stomach cancer.

Methodology
•    This study, conducted in 1996, was a long-term questionnaire-based study that recruited men and women aged 50 to 71 from six states throughout the United States.
•    The participants were asked to complete an initial questionnaire that quizzed them about their lifestyle and eating habits.
•    After six months, those participants who did not have cancer filled out another questionnaire about the frequency of meat consumption and cooking methods.
•    Follow-up of the participants began in 2006 by analyzing cancer registry databases to find incidences of cancer among them.

Results
•   There was a total of approximately 840 patients with esophageal cancers and 950 patients with gastric cancers from all the studies that were considered.
•   Men were found to consume more red meat than women. Most of those who consumed red meat also tended to have fewer vegetables in their diet and were smokers.
•    Red meat intake was positively associated with a type of esophageal cancer but white meat and processed meat were not associated with either of the cancers investigated in this study.
•    Risk of stomach cancer increased with consumption of a chemical (DiMeIQx) that is formed in charred red meat.

Shortcomings
In this study, the large number of participants enabled the researchers to study a variety of stomach and esophageal cancers; however, in some of the categories there were very few cases for it to be considered statistically significant. Also there may have been some “misclassification” of cancerous tumors due to proximity of their origin sites. The authors also claim that they could have underestimated nitrate and iron content due to unavailability of sufficient data regarding these two components. Finally, the researchers state that there may have been other factors like lifestyle and/or infections that affected the incidence of the studied cancers.

Conclusion
There was a definite association found between ingestion of red meat and cancer of the esophagus, while cancer of the stomach — especially in the upper region of the stomach — was associated with ingestion of the chemical DiMeIQx. Until now, red meat was a “limited suggestive increased risk” for esophageal cancer, but this study establishes a clear link between the two. This could suggest necessary alterations in diets which have excess red meat, especially those that use the grilling and roasting methods of cooking. It is, however, important to note that neither white meat nor processed meat was associated with either of these cancers.
For More Information:
Red Meat Consumption and Risk of Esophageal and Gastric Cancers

Publication Journal: The American Journal of Gastroenterology, October 2010
By Amanda J. Cross, PhD; Neal D. Freedman, PhD; National Cancer Institute, National Institutes of Health, Rockville, Maryland

*FYI Living Lab Reports Are Summaries of the Original Research.
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