Updated

Scientists at UC San Francisco have identified a slow gut-to-brain dopamine pathway that may explain why people gradually come to enjoy bitter coffee and other initially unpleasant flavors, according to a ScienceDaily report published November 9, 2026. The research, published November 4 in Nature and led by senior author Zachary Knight with James Grove, focuses on a slower dopamine system that responds to nutrients after food is consumed, rather than the rapid dopamine signals triggered by seeing or tasting a reward. In mice, nutrients delivered directly into the stomach produced a prolonged dopamine response in the anterior basolateral amygdala, or BLA. When the researchers disrupted this pathway, mice kept eating normally but failed to learn that a new flavor predicted calories. When they artificially activated dopamine fibers in the BLA after a calorie-free flavor, the mice came to prefer that flavor. Researchers also reported similar patterns in humans, using a PET study of 13 men analyzed by Dana Small of Yale University and an fMRI study of 38 adults led by Marc Tittgemeyer. In both mice and people, the response was considerably stronger in the left BLA than the right, a asymmetry that surprised Knight. The article says why the left side dominates remains unanswered, and Knight's laboratory is now investigating it. ScienceDaily framed the work as potentially useful for reshaping eating habits and food preferences, but the article itself does not establish any specific treatment.