Drinking alcohol, eating processed meat, and being overweight can each increase an individual's chance of developing stomach cancer.
Alice G. Bender, MS, RDN
Drinking alcohol, eating processed meat, and being overweight can each increase an individual’s chance of developing stomach cancer, according to a recent report by the American Institute for Cancer Research (AICR) and the World Cancer Research Fund (WCRF).1
“All of these were new links to stomach cancer,” Alice G. Bender, MS, RDN, head of Nutrition Programs at AICR said, noting other previously established risk factors, such as tobacco use, infection, and chemical exposure.
Twelve of the 18 studies looked at regarding alcohol and stomach cancer incidence showed that there was a correlation between the two. Furthermore, of the 8 studies that considered stomach cancer mortality and alcohol intake, 7 reported a positive correlation.
However, the amount of alcohol an individual drinks has an effect on his or her risk for developing stomach cancer. In fact, 23 of the 30 studies considered in the larger dose-response meta-analysis (n=11,926) showed that there was no significant association for risk in people who drank 10 grams of alcohol per day (95% CI, 1.01-1.04). The association became significant when daily intake reached 45 grams (about 3 cups) per day. Additionally, when stratified by gender and location, men and people living in Asia showed increased incidence rates.
Bender said that the number of drinks per day associated with risk is unique for different types of cancers.
“When they look at this, they begin to look at where does risk increase significantly enough. In this case, for stomach cancer, it begins at 3 drinks a day. They don’t see a change in risk, overall, at one or two drinks. But we know in other cancers, the risk starts with an even smaller amount of alcohol,” Bender noted.
The AICR recommends that if adults choose to drink, they should limit their intake to one drink per night for women and two drinks per night for men.
Processed meats, which were defined as “meat items that have undergone salt-preservation, smoking, or fermentation,” and include foods such as sausage, bacon ham, meatballs, burgers, and cold meats, were also linked to an increase in stomach cancer risk.
While conclusions could not be drawn for cardia cancer, three studies found that those with the highest levels of intake for processed meat had more of a risk for stomach cancer than the lowest intake group. These studies were included in the dose-response meta-analysis (n= 1,149), which ultimately found that eating 50 grams of processed meat per day resulted in an 18% increased risk of non-cardia cancer (95% CI, 1.01-1.38).
Scientists speculate that the high levels of nitrate and nitrite, which preserve the meat and give it distinct color, are prominent factors in the reason why processed meat can be a carcinogen. “In the stomach in particular, nitrite and nitrate can react with the degradation products of amino acids (from meat) to form N-nitroso compounds. Several N-nitroso compounds are known human or animal carcinogens,” the study reads.
Bender said that processed meats were linked to colorectal cancer back in 2007, and came up again as a risk factor when reevaluated in 2012. Now that processed meats have also been linked to stomach cancer, she recommends limiting consumption.
Researchers even noted modern refrigeration and transportation of food, which allows for a higher consumption of fruit and vegetables and less relying on salt-preserved foods, as one of the multiple reasons why stomach cancer incidence has been declining.
Body Mass Index (BMI)
As was the case with processed meats, conclusions regarding body fatness, measured by body mass index (BMI), could only be made for cardia cancer. However, researchers did find an inverse association between BMI and H pylori infection, which is a known risk factor for non-cardia cancer.
The dose-response meta-analysis included 7 studies reporting on cardia cancer (n= 2,050). Results showed that for every 5 kg/m², there was a 23% increase in the risk of developing cardia stomach cancer (95% CI, 1.07-1.40).
Being overweight or obese causes elevated levels of insulin and leptin and upregulation of the production of hormones like sex steroids and insulin. This can promote cancer cell growth by increasing cell proliferation and impairing apoptosis, the researchers said in the report.
“Now we have 11 cancers that we have linked to being overweight or obese, adding more information to the fact that we really need to look into how we can make changes in our lives to help adults and children,” Bender said. “We don’t want people to feel that we’re blaming them. That’s certainly not what our message is. It’s a positive thing that we can lower our risk by taking steps such as being more active, and taking a look at your plate and making changes that can promote health in the long run.”
Other Potential Factors
The study also considered other factors and their relation to stomach cancer risk but found them to be inconclusive, signaling a possibility for more research on the future.
They found that there was limited evidence that consuming grilled (broiled) or barbecued (charbroiled) meat and fish, eating red meat, or eating a diet low in fruit could increase a person’s chance of developing stomach cancer. Also, while some studies suggest that an increase in the amount of citrus fruit in one’s diet could lessen his or her risk for stomach cancer, researchers found the evidence to fall short for that factor as well.
“There were some intriguing associations. Though the evidence wasn’t strong enough to make the link, it’s emerging research and we’re going to continue to look into that,” Bender said.
1) World Cancer Research Fund International/American Institute for Cancer Research. Continuous Update Project Report: Diet, Nutrition, Physical Activity and Stomach Cancer. 2016. Available at: wcrf.org/stomach-cancer-2016.