Study reveals fructose consumption may silently increase inflammation levels - Video

Fructose, the sugar found in many sweetened drinks and processed foods, may do more harm than just add calories. Researchers at the University of Vienna, led by Ina Bergheim, discovered that even short-term fructose consumption causes immune cells called monocytes to become more sensitive to bacterial toxins, increasing inflammation in the body.

Their findings, published in Redox Biology, shed new light on how diet influences immune defenses and infection risk.

The team conducted two randomized studies with healthy adults, comparing the immune response after drinking fructose-sweetened beverages versus glucose-sweetened ones. They also isolated monocytes and ran cell culture tests to understand the biological mechanisms behind this sensitivity. Results showed that fructose—but not glucose—raised levels of Toll-like receptor 2 (TLR2) on monocytes.

TLR2 plays a crucial role in detecting bacterial toxins, and its increase made immune cells far more reactive to a toxin called lipoteichoic acid. This led to elevated release of inflammatory messengers like interleukin-6, interleukin-1β, and tumor necrosis factor-alpha-signals that can cause tissue damage if overproduced.

These findings reveal for the first time that fructose consumption primes the immune system in a way that might backfire by escalating harmful inflammation during infections. The researchers caution that even healthy people can experience this immune priming from brief periods of high fructose intake.

Broader implications concern people with metabolic disorders such as type 2 diabetes and fatty liver disease, who are already prone to inflammation and infection. Long-term fructose intake likely worsens these risks, and further research is needed to confirm these effects and explore preventive dietary strategies.

Overall, this study highlights a hidden danger in common dietary sugars: fructose not only affects metabolism but actively changes immune responses, potentially making infections worse. Reducing intake of sugary drinks and processed sweets emerges as a vital step toward healthier immune function and lowering infection risks for all.

REFERENCE: Raphaela Staltner, Katja Csarmann, Amelie Geyer, Anika Nier, Anja Baumann, Ina Bergheim. Fructose intake enhances lipoteichoic acid-mediated immune response in monocytes of healthy humans. Redox Biology, 2025; 85: 103729 DOI: 10.1016/j.redox.2025.103729