Potential Impact of Caffeine on Blood Transfusion Effectiveness

A recent study conducted by researchers at the University of Colorado Anschutz Medical Campus indicates that caffeine—the most widely consumed psychoactive substance—may negatively influence blood storage quality and transfusion outcomes. The research highlights that higher caffeine levels in donors' blood are associated with red blood cells (RBCs) that are more susceptible to damage during storage and less effective when transfused into patients.

The study, part of the REDS RBC-Omics project analyzing over 13,000 blood donors, reveals that elevated caffeine levels are linked to decreased post-transfusion hemoglobin levels and increased hemolysis, which is the breakdown of RBCs. These effects are particularly significant in recipients and donors with certain genetic variants, such as the ADORA2b gene, that influence RBC function under low-oxygen conditions. This suggests a shift toward more personalized transfusion strategies that consider both genetic factors and lifestyle, including caffeine intake.

ngelo D'Alessandro, Ph.D., emphasizes the importance of these findings, noting that while caffeine's effects on the brain and nervous system are well-known, its impact on blood cell biology is a new discovery. He suggests that transient modifications in caffeine consumption around the time of blood donation could potentially improve blood quality and transfusion success. This approach aligns with European guidelines, where donors are advised to limit caffeine intake prior to donation, but contrasts with practices in other regions like the United States and Italy, where caffeine consumption before donation is often not discouraged due to its short-term benefits such as increased blood pressure and vascular tone.

Interestingly, the research sheds light on caffeine's role in exercise performance, revealing that it increases oxidative stress in RBCs by blocking specific receptors and enzymes involved in antioxidant pathways. Paradoxically, this increase in oxidative stress may promote beneficial physiological adaptations, such as improved exercise tolerance noted in G6PD-deficient mice.

Overall, the findings suggest that dietary caffeine intake can significantly influence blood donation and transfusion outcomes. Moderate caffeine consumption may have both advantages and drawbacks, and personalized approaches considering genetic and lifestyle factors could enhance the safety and effectiveness of blood transfusions.

[Source: https://medicalxpress.com/news/2025-09-caffeine-undermine-blood-transfusion-effectiveness.html]