Do milk proteins relieve capsaicin-induced burning sensation in the oral cavity?

Milk has a soothing effect on the capsaicin-induced burning sensation in the mouth. This double-blinded, placebo-controlled, cross-over study aimed to investigate if milk proteins could relieve the capsaicin-induced burning sensation. During each session, the tongue of each participant was exposed to capsaicin twice for 8 min in total. Subsequently, the participants rinsed the mouth with one of three solutions: 5% casein, 5% whey protein, or water. The participants rated the perceived unpleasantness and burning sensation during capsaicin exposure and after rinsing on numerical rating scales. Thermographic imaging and semi-quantitative sensory testing were performed at baseline, after capsaicin exposure, and after rinsing. No significant differences were observed between sessions in any of the measured parameters (p >= .053). Scores for unpleasantness and burning sensation varied over time (p <= .006). Heat and mechanical sensitivity changed over time (p < .001). In conclusion, rinsing with milk protein solutions did not have any robust effect in this study design.