Daily sugary drinks linked to more than double stomach cancer risk

Researchers tracking the health of more than 112,000 American adults over decades found something worth paying attention to: people who drink sugary beverages every day face more than twice the risk of developing stomach cancer compared with those who rarely consume them. The study, published in Gastro Hep Advances and conducted by scientists at Mass General Brigham, examined dietary records and health outcomes from two long-running cohorts—the Nurses' Health Study and the Health Professionals Follow-up Study. Over the course of follow-up, 278 participants developed gastric cancer. When researchers compared daily consumers of sugar-sweetened drinks to those drinking fewer than one per month, the difference was stark: a 2.45-fold increased risk after accounting for other known risk factors.

The beverages in question are familiar fixtures in American life. Regular sodas, sweetened teas and coffees, sports drinks, energy drinks, and fruit drinks all fall into this category, and many contain substantial amounts of fructose derived from high-fructose corn syrup. According to older data from the Centers for Disease Control and Prevention, nearly 65 percent of U.S. adults report consuming at least one sugar-sweetened beverage daily. The association appeared particularly pronounced among women who drank more than one of these beverages per day. Notably, artificially sweetened beverages showed no increased risk of gastric cancer, suggesting that sugar itself—not the act of drinking sweetened liquids—drives the association.

Andrew Chan, a gastroenterologist and epidemiologist at Mass General Brigham's Cancer Institute, emphasized the scale of the finding: "Consuming at least one sugar-sweetened beverage per day was associated with more than twice the risk of developing gastric cancer compared with those who never consumed these beverages." The study also identified a particular culprit within these drinks. Higher intake of fructose correlated with greater incidence of stomach cancer, pointing to a possible mechanism beyond simple calorie consumption. Chan suggested that fructose may activate specific insulin and metabolic pathways that differ from those triggered by artificial sweeteners.

Yet the study cannot prove that sugary drinks cause stomach cancer. This is an observational study, meaning researchers watched what people already drank and then tracked their health outcomes—they did not randomly assign some people to consume soda and others to avoid it. The distinction matters. Many other factors influence stomach cancer risk: bacterial infections like Helicobacter pylori, body weight, smoking, alcohol use, and overall diet all play roles. The researchers had limited information on H. pylori status for most participants, a significant gap given that this infection is an established risk factor for gastric cancer. Weight gain and metabolic changes from regular sugary drink consumption could themselves increase cancer risk, as could chronic inflammation or shifts in the gut microbiome. "We don't know the exact mechanism," Chan acknowledged, "but several biological pathways have been proposed."

Understanding the difference between relative and absolute risk is crucial for interpreting the findings. A 2.45-fold increase sounds alarming, but it describes relative risk—the likelihood of an outcome in one group compared with another. The absolute risk tells a different story. Among the 112,284 participants in the study, only 278 developed stomach cancer over the entire follow-up period, making gastric cancer relatively uncommon in this population. Someone who occasionally drinks soda is not facing an imminent diagnosis. Still, the evidence accumulates. Regular consumption of sugar-sweetened beverages is already linked to weight gain, obesity, type 2 diabetes, and cardiovascular disease. This study adds stomach cancer to that list of potential harms.

Chan's recommendation is straightforward: cutting back on sugary drinks is a reasonable, low-risk step. The benefits extend beyond cancer prevention to include reduced risk of diabetes and obesity. For those looking to reduce intake, practical options exist. Swapping sugary beverages for water or unsweetened alternatives is the most direct approach. Gradually diluting soda with sparkling water can ease the transition. Reading labels to identify added sugars and high-fructose corn syrup helps consumers make informed choices. The findings add to a growing body of research suggesting that what we drink matters—not just for our waistlines, but for our cells. More research is needed to confirm the association and understand why it exists, but the pattern is becoming harder to ignore.