August 20, 2026, 11:01 am | Read time: 4 minutes
There is now a wealth of scientific evidence on how harmful added sugar in foods is to our health. Nutrition experts and doctors agree that sweetened soft drinks should be avoided. A recent study now shows the impact sugary drinks have on the risk of stomach cancer.
According to the Federal Statistical Office, around 93 liters of sugary soft drinks such as cola and other sodas were produced per capita in Germany alone in 2024.1 That equates to about one glass per day. It’s not just the empty calories from soft drinks that are a problem. Researchers found that even one sugary drink per day is enough to significantly increase the risk of stomach cancer.2
What Was the Study About?
U.S. researchers from Massachusetts General Hospital and Harvard Medical School conducted a prospective cohort study to examine whether the consumption of sugary soft drinks and drinks with artificial sweeteners is associated with stomach cancer. The results were published in advance in the journal “Gastro Hep Advances.”
For the study, the researchers used data from two ongoing long-term studies involving people working in the U.S. health system. The “Nurses’ Health Study” (NHS) has been tracking 121,700 female nurses since 1976. The “Health Professionals Follow-up Study” (HPFS) has been tracking 51,529 men working in the health sector since 1986. Participants who provided detailed information about their beverage consumption were included in the data analysis. Participants completed a mailed questionnaire at the start of the study and every two years thereafter to provide data on lifestyle factors, medical history, and disease progression.
The researchers distinguished between two groups of beverages:
- sugary drinks such as sodas and sports drinks
- sugar-free, low-calorie drinks such as sodas and sports drinks with sweeteners
A serving of the drinks was defined as approximately 240 milliliters. Participants were asked to indicate how often they consumed the drinks:
- almost never (less than one serving per month)
- one to three servings per month
- one to three servings per week
- four to seven servings per week
- more than one serving per day
Over the years, the researchers tracked which participants developed stomach cancer. Participants reported their stomach cancer diagnoses through self-reports in the biennial questionnaire. Medical records were also used to confirm cancer diagnoses. Other risk factors, such as the consumption of red meat, were mathematically adjusted for in the data analysis.
What the Study Analysis Revealed
Of the 112,284 participants (68,311 women and 42,973 men) included in the final analysis, 278 developed stomach cancer. The data analysis revealed that individuals who consumed at least one serving of sugary soft drinks per day had a 2.45 times greater risk of stomach cancer compared to those who did not drink sweetened soft drinks. There was also a gender difference: Women who consumed at least one sugary drink per day had approximately three times the risk of developing stomach cancer, while men had about double the risk, both compared to people who did not consume sugar-sweetened drinks.
Interestingly, there was no evidence that the consumption of low-calorie soft drinks with sweeteners increased the risk of stomach cancer. Additionally, the researchers examined a smaller group of participants to see if there were possible links to colon cancer. The data showed that neither consumers of sugary soft drinks nor those with artificial sweeteners had an increased risk of colon cancer.
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Why Do Sugary Drinks Increase Stomach Cancer Risk?
According to the researchers, this is the first study to show a link between the consumption of sugary drinks and the risk of stomach cancer. However, the scientists do not yet have a clear explanation for why sugar might increase the risk of stomach cancer. They suspect that factors such as weight gain, insulin resistance, steroid hormone imbalance, inflammation, and DNA damage could lead to stomach cancer. “The exact mechanism of the carcinogenic effects of sugar-sweetened beverages still needs to be investigated. Future studies must verify our results and explore the potential biological mechanisms behind them,” the researchers stated in the study analysis.
Limitations of the Study
As always, it is important to note that this type of observational study can only show correlations in the data, not causal effects. In other words, we cannot conclude that it was the consumption of sugary drinks that directly led to the development of stomach cancer in the participants. Other factors may also have contributed to the higher risk of stomach cancer. Additionally, the study is largely based on self-reports from participants who completed questionnaires. This can lead to subjective and inaccurate reporting.
Further limitations of the study include that the researchers had limited information on Helicobacter pylori infections. This is a type of bacteria that infects the stomach and is another known risk factor for stomach cancer. There were also incomplete data on health history and family medical history.