More than fat – Proteins in dairy and plant milks contribute to the reduction of oral burn from capsaicin

Abstract

The effectiveness of cow’s milk in reducing capsaicin-induced burn is well-known, and typically attributed to capsaicin’s lipophilicity. Still, controlled laboratory studies show full-fat milk is not more efficacious than fat-free milk, suggesting other components may contribute to milk’s effectiveness. Recent research has shown milk proteins like micellar casein and whey reduce capsaicin burn in the absence of fat. This paper reports two experiments in moderate capsaicin users that investigate the efficacy of dairy and plant milks varying in fat and protein content. In Experiment One, participants were exposed to 5-ppm capsaicin solutions before rinsing with conventional full-fat milk, ultra-filtered full-fat milk, almond milk, soy milk, and pea protein-enriched flax milk. In Experiment Two, they rinsed with fat-free, conventional full-fat, and ultra-filtered full-fat milk, and three soy milks of varying protein content. Participants made burn ratings on a general Labelled Magnitude Scale (gLMS) once every 10 s for 2-min (Experiment One) or continuously for 2-min (Experiment Two). Experiment One showed significant main effects of time and sample, with planned comparisons revealing differences for water versus conventional and ultra-filtered full-fat milk. In Experiment Two, a main effect of time and a time-by-sample interaction were observed, with samples in both blocks (soy milk, dairy milk) significantly outperforming water. Some evidence of a concentration-dependent effect was observed for protein, with both experiments suggesting ultra-filtered high protein full-fat milk was most efficacious. These findings suggest proteins play a role in mitigating capsaicin burn, although further research is needed to quantify the relative contributions of fat and protein.