- One sugar-sweetened beverage each day was associated with a 2.45 times higher risk of gastric cancer compared to less than one such beverage a month.
- Artificially sweetened drinks showed no similar association.
- About 63% of U.S. adults drink at least one sugary beverage daily.
A new, decades-long study from Mass General Brigham has sobering news for people who regularly consume sugar-sweetened beverages: Drinking at least one a day more than doubles the risk of developing stomach cancer, compared to those who seldom consume sugary drinks.
The same link was not found with artificially sweetened beverages, based on the data gathered from more than 100,000 people. Study findings were published in the journal Gastro Hep Advances.
That news could impact a lot of Americans, as nearly two-thirds (63%) of U.S. adults say they drink one or more sugar-sweetened beverages daily.
In the study, sugar-sweetened drinks include carbonated beverages, punch, lemonade and sports drinks, while artificially sweetened beverages were defined as low-calorie carbonated beverages in this study, per the researchers. The Centers for Disease Control and Prevention has a slightly different list that adds fruit drinks, sports drinks, energy drinks and sweetened waters, as well as flavored coffees and any coffee and tea to which sugar or flavored creamers are added.
In a news release announcing the research, Mass General Brigham noted that sugar-sweetened drinks have already been linked to a greater risk of colorectal, breast and liver cancers. The study on stomach cancer looked at data from 112,284 people who were part of the Nurses’ Health Study and Health Professionals Follow-up Study. Each of those included meticulous data on diet, lifestyle and health of U.S. adults over “many decades.” In follow-up, it was shown that 278 participants developed stomach cancer.
“This is the first study to demonstrate an association between sugar-sweetened beverage intake and gastric cancer in a U.S. population,” said senior author Dr. Andrew T. Chan, a gastroenterologist and epidemiologist with the Mass General Brigham Cancer Institute, in the written statement. “Gastric cancer is the fifth leading cause of cancer death worldwide, but we’ve known very little about how diet might contribute to this cancer.”
What’s behind the findings?
Why sugary drinks could be linked to stomach cancer is not clear and will require more research, they said. But the study lists several possibilities, including weight gain, insulin resistance, steroid hormone imbalance, inflammation, damage to DNA and an imbalance among the microorganisms in the gut.
The researchers took into account confounding factors that could contribute to that increased risk. After eliminating those, they found that men and women having one or more sugar-sweetened drinks a day faced a 2.45-times raised risk of gastric cancer compared to those who had less than one serving a month.
High fructose consumption — and that’s the main sweetener in drinks — in general raises stomach cancer risk. For women in the nurses’ study, daily consumption was associated with a 3.04-fold higher risk of stomach cancer, compared to those rarely having such drinks.
“Because Helicobacter pylori (H. pylori) infection increases the risk of gastric cancer, researchers also assessed H. pylori status in a subset of 940 participants. While just over one third of these participants had evidence of H. pylori infection, there was no association between sugar-sweetened beverage consumption and infection,” the release noted.
H. pylori is a bacteria in the lining of the stomach that is often without symptoms, according to MedlinePlus. But for some, it causes stomach inflammation, ulcers and for some, increased risk of stomach cancer.
Some study limitations
The researchers noted some limitations, including its observational design. They also reported the possibility the higher rates of stomach cancer was due to something else. They didn’t have much information on whether participants had H. pylori or a family history of the cancer. Nor was the population of participants diverse, making it hard to look at whether there were racial or ethnic differences.
But they said that because the detailed data on health and lifestyle was gathered over many years, they were able to control for many other possible risk factors for stomach cancer.
“Rethink your drink”
The CDC recommends those who regularly drink sugar-sweetened beverages “rethink your drink.” In a section under healthy weight and growth headings, the public health agency said sugary drinks are the leading source of added sugars that Americans consume. That can lead to health problems including “weight gain, obesity, type 2 diabetes, heart disease, cavities and gout.”
The CDC article notes that one 12-ounce can of regular soda contains more than 10 teaspoons of added sugar.
The CDC highly recommends that people read the nutrition labels on food and drinks to see how much sugar is added. Added sugars aren’t typically called that on the labels. The list includes cane sugar, corn syrup dextrose, fructose, fruit juice concentrates, fruit nectars like agave nectar, glucose, high fructose corn syrup, honey, malt syrup, maple syrup, molasses, raw sugar, sucrose and sugar cane.
For those struggling to cut back on sugar-sweetened drinks, the CDC has a list of tips that emphasize drinking more water, but also suggests ways to get flavor or fizz in healthier ways without added sugars.
More research on artificial sweeteners
While the study raises concerns about sugar, separate research offers some reassurance about sugar substitutes in beverages.
An unrelated review of previous studies conducted by researchers at the University of Ljubljana and Wageningen University & Research, the University of Leeds and colleagues from other institutions in the Netherlands, Denmark, Spain and Belgium, found “no evidence that sugar substitutes harm weight, health or sweet taste preferences.”
Findings were published in the journal Nutrients.
Said Graham Finlayson at the University of Leeds, “A common concern is that replacing sugar with non-nutritive sweeteners might lead to a stronger preference for sugary sweet foods or stimulate appetite. Across these controlled studies, that prediction was not supported. Sweeteners are not a weight-management strategy by themselves, but they can provide a useful way to reduce sugar while retaining sweetness within a broader healthy diet.”
They also noted that markers like blood sugar, insulin, blood pressure, cholesterol and liver enzymes were comparable in both the sweetener and non-sweetener groups.