For years, scientists have been trying to determine the mechanism linking sugary drinks with an increased risk of diabetes.
Now, a new study published in Cell Metabolism suggests that the answer may lie in our gut microbiome—the trillions of bacteria that live in our digestive system and help regulate metabolism.
Why Sugary Drinks Are Worse Than Other Sugars
Sugary beverages are the largest source of added sugar in the U.S. diet. Unlike sugars found in solid foods, the sugar in drinks is quickly absorbed by the body, causing rapid spikes in blood sugar levels. This can make them more harmful than other sources of added sugar.
“They have a really high energy density because they’re just sugar and water,” study author Qibin Qi explained in a recent statement.
How the Gut Microbiome is Involved
Previous research has shown that sugar-sweetened beverages can alter the composition of gut bacteria, but this is the first study to link those changes to metabolism and diabetes risk.
To do this, researchers from Albert Einstein College of Medicine analyzed data from the ongoing Hispanic Community Health Study/Study of Latinos (HCHS/SOL), a wide-ranging study with over 16,000 participants living in Miami, San Diego, Chicago, and the Bronx. The team tracked their dietary habits and examined their blood and gut microbiomes.
Their findings revealed that people who consumed two or more sugar-sweetened beverages daily had distinct differences in their gut bacteria and blood metabolites compared to those who drank fewer or no sugary drinks. These metabolic changes were linked to a higher likelihood of developing diabetes over the next ten years.
The team analyzed gut bacteria from over 3,000 participants and found that high sugary beverage intake was associated with changes in nine bacterial species. Four of these species produce short-chain fatty acids, compounds that help regulate glucose metabolism.
From their findings, the researchers concluded that many sugary drinks may disrupt the normal balance of gut bacteria, leading to metabolic changes that increase the risk of diabetes. Interestingly, these changes were not observed in people who consumed sugar from solid foods, suggesting that liquid sugar may uniquely impact gut health.
“Although our findings are observational, they provide insights for potential diabetes prevention or management strategies using the gut microbiome,” added Qi.
Blood Metabolites as Early Warning Signs
The study also identified 56 blood metabolites associated with high sugary beverage intake. Some of these metabolites, produced by gut bacteria, were linked to negative metabolic traits, such as higher blood sugar and insulin levels, higher BMI, and lower levels of “good” cholesterol. Individuals with elevated levels of these metabolites were more likely to develop diabetes within ten years.
“We found that several microbiota-related metabolites are associated with the risk of diabetes,” says Qi. “In other words, these metabolites may predict future diabetes.”
Limitations Remain
While the study provides strong evidence of a connection between gut bacteria, sugary drinks, and diabetes, the researchers acknowledge some limitations. For example, they couldn’t determine whether specific gut bacteria directly cause diabetes. Future studies will explore whether modifying gut bacteria—through diet, probiotics, or other interventions—can reduce diabetes risk.
The team also plans to investigate whether gut microbial changes linked to sugar consumption contribute to other health problems, such as heart disease.
“In the future, we want to test whether the bacteria and metabolites can mediate or at least partially mediate the association between sugar-sweetened beverages and risk of diabetes,” said Qi.
Kenna Hughes-Castleberry is the Science Communicator at JILA (a world-leading physics research institute) and a science writer at The Debrief. Follow and connect with her on BlueSky or contact her via email at kenna@thedebrief.org