Effects of capsaicin and menthol on oral thermal sensory thresholds

ObjectiveTo determine the long-term effect of capsaicin and short-term effect of menthol on oral thermal thresholds.DesignThe thresholds for cold detection (CDT), warm detection (WDT), cold pain (CPT) and warm pain (WPT) were determined in 11 regular chilli-eaters (capsaicin group) and 11 control subjects that were closely matched for age, gender and ethnicity. The effect of menthol was determined by asking all 22 participants to suck a lozenge containing 0.52% menthol for 5 min.ResultsAn ANOVA revealed a significant difference between the capsaicin and control groups (P = 0.014), with the greatest difference in the WDT (capsaicin group 4.7 ± 2.7 [S.D.] °C; control group 2.3 ± 2.2 °C). Immediately after sucking a menthol lozenge there was a significant rise in the CDT (2.2 ± 1.1 °C to 5.9 ± 6.2 °C; P < 0.01) and WDT (3.6 ± 2.7 °C to 7.6 ± 4.4 °C; P < 0.001).ConclusionsThe consumption of foods containing capsaicin and menthol significantly alters thermal sensory thresholds in the oral cavity. Dietary habits should therefore be taken into account when intra-oral thermal thresholds are determined.