There is currently substantial evidence that consuming higher amounts of meat—particularly red and processed meat—increases the risk of developing cancer. However, not all studies show such a link, and researchers are seeking greater clarity, especially regarding specific types of cancer.
A new study published in the International Journal of Cancer by an international team of researchers takes a closer look at the link between meat consumption and cancers of the stomach and esophagus—specifically adenocarcinoma, a type of cancer that begins in glandular cells.
In recent years, there has been a rise in cases of esophageal adenocarcinoma (EAC), and esophageal cancer overall currently ranks 11th among the most common cancers worldwide. Stomach cancer is even more prevalent, ranking fifth on the list.
The research team analyzed data from 450,112 individuals participating in a long-term health study, including information on diet and cancer incidence. Participants were followed for an average of 14.1 years, revealing clear correlations as well as some unexpected findings.
“Higher consumption of processed meat was associated with an increased risk of stomach cancer—particularly the intestinal type—and esophageal adenocarcinoma,” the researchers write in their paper. “This study provides new evidence regarding the role of meat consumption in the context of stomach and esophageal cancer.”
The researchers calculated that consuming an additional 30 grams of processed meat per day is associated with a 9 percent increase in the risk of stomach cancer and a 13 percent increase in the risk of esophageal adenocarcinoma. However, the study also separately analyzed unprocessed red meat and unprocessed white meat, revealing some interesting results. First, no significant link was found between unprocessed red meat and these specific types of cancer.
Second, a 20-gram daily increase in white meat consumption was associated with a 20% higher risk of developing cancer in the lower and middle parts of the stomach in women; no such association was found in men.
Researchers suggest that several factors may be at play, including the carcinogenic effects of chemicals used during cooking and byproducts of protein breakdown in the body (white meat is rich in protein). However, the study focused on identifying associations rather than explaining them.
“Although white meat is often considered healthier than red or processed meat, the potential increased cancer risk linked to protein metabolism, microbiota changes, and cooking methods warrants further investigation,” the researchers write.
There are many more known potential pathways linking processed meat consumption to cancer, so this finding is not unexpected. For example, chemicals formed during the consumption of red meat can damage DNA and increase oxidative stress in cells, thereby raising the likelihood of developing cancer.
“For processed meat, processing and storage methods are also key factors that may increase the risk of stomach cancer and esophageal adenocarcinoma,” the researchers note. “In this context, processed meat consumption contributes to higher salt intake; salt has been shown to irritate the stomach lining and cause significant damage and inflammation within the stomach.” While the long follow-up period and large number of participants are key strengths of the study, the research alone cannot prove a causal link. Meat consumption habits were assessed only once—at the start of the study—and may have changed in the years that followed.
Despite these limitations, and considering the body of evidence from previous studies, the case against consuming processed meat is only growing stronger. The study authors believe that action is now needed, as an extra sausage or slice of bacon could be detrimental to health.
“Processed meat may increase the risk of stomach cancer and esophageal adenocarcinoma, although further research is needed to clarify the impact of white meat consumption,” the researchers write. “Future studies should elucidate the underlying mechanisms and develop dietary guidelines to reduce cancer risk.”
About the Author
