A long-term investigation involving more than 112,000 participants has identified an association between frequent consumption of sugar-sweetened beverages and a higher incidence of gastric cancer.

The research also found a different pattern for artificially sweetened beverages, which were not associated with higher gastric cancer incidence after adjustment for several relevant factors.

Long-Term Evidence & Study Design

The investigation drew information from two large U.S. health studies: the Nurses' Health Study and the Health Professionals Follow-Up Study. Combined data covered 112,284 participants, with dietary habits, lifestyle characteristics and health outcomes followed over many years.

During the follow-up period, 278 participants developed gastric cancer. Researchers compared beverage consumption patterns with later cancer diagnoses while taking several potentially relevant factors into account.

Long-term observational research can be valuable for studying dietary habits because eating and drinking patterns can be assessed over extended periods. However, this type of research also has an important limitation.

Daily Consumption & Higher Observed Risk

Participants who reported consuming at least one serving of a sugar-sweetened beverage each day had a 2.45-fold higher observed risk of gastric cancer compared with participants consuming less than one serving per month. The association appeared in both women and men. Researchers also reported a relationship between higher total fructose intake and increased gastric cancer incidence.

Among women, a separate analysis found that consuming more than one sugar-sweetened beverage per day was associated with a 3.04-fold higher risk compared with very infrequent consumption. These numbers describe relative differences between groups rather than predicting what will happen to a particular person.

What Counts as a Sugary Beverage & Artificial Sweeteners

The study included several commonly consumed beverages within its definition of sugar-sweetened drinks. These included carbonated beverages, punch, lemonade and sports drinks.

Researchers examined artificially sweetened beverages separately, focusing on low-calorie carbonated drinks. After statistical adjustment, higher consumption of these beverages did not show the same association with gastric cancer incidence.

Fructose & Possible Biological Questions

The findings involving total fructose intake provide another area for scientific investigation. Sugar-sweetened beverages can provide substantial quantities of added sugars, while fructose was specifically examined in the study's dietary analysis.

The research did not establish a biological pathway connecting fructose or sugary beverages directly to gastric cancer. Several possibilities could be examined in future research, including metabolic processes, broader dietary patterns and changes in the gastrointestinal environment.

H. pylori & Another Piece of the Evidence

Researchers also considered Helicobacter pylori, commonly known as H. pylori, because infection with this bacterium is an established risk factor for gastric cancer. H. pylori information was available for a subset of 940 participants. Slightly more than one third showed evidence of infection, but the researchers did not identify an association between sugar-sweetened beverage consumption and H. pylori infection within this smaller group.

This finding does not diminish the established importance of H. pylori in gastric cancer research. Instead, it indicates that the available data did not show a relationship between beverage consumption and H. pylori infection within the subgroup examined.

Expert Insight

Andrew T. Chan, MD, MPH, senior author of the research and a gastroenterologist and epidemiologist at Mass General Brigham Cancer Institute, discussed the significance of the findings in the institution's official research announcement. “This is the first study to demonstrate an association between sugar-sweetened beverage intake and gastric cancer in a U.S. population.”

Why Cause & Effect Cannot Be Claimed

The observational design is essential when interpreting the results. Researchers observed participants' existing beverage habits and subsequently recorded health outcomes rather than assigning specific beverages under controlled experimental conditions.

For that reason, the findings cannot establish that sugar-sweetened beverages directly caused gastric cancer. Frequent consumers may differ from infrequent consumers in dietary habits, lifestyle characteristics or other factors that cannot be measured completely.

What Future Research Needs & Why It Matters

Further investigations could determine whether the association appears consistently in other populations and research settings. Studies involving broader demographic groups could help clarify whether dietary patterns, socioeconomic circumstances, geographic differences and genetic factors influence the relationship.

Researchers could also investigate possible biological mechanisms. Greater understanding of whether the association relates specifically to sugar exposure, overall dietary patterns, beverage-related metabolic effects or another factor would help explain the statistical findings.

The findings remain observational, meaning a direct cause-and-effect relationship has not been established. Future research across broader populations and with different study designs will help determine whether the association can be reproduced and what biological processes may explain it.