Change in Taste Preference to Capsaicin and Catechin Due to Aging in Mice

Taste is a chemical sensation that primarily detects nutrients present in food, and maintenance of taste sensations is important for ensuring that older people have a balanced nutritional diet. While several reports have suggested that taste sensitivity changes with age, the molecular mechanisms underlying this phenomenon are still unclear. Previous studies on the matter have focused mainly on the relationship between aging and taste detection of specific basic taste-inducing substances, and other than for these basic substances, understanding of how aging affects the detection of taste is limited. Therefore, to understand the effect that aging has on the taste detection of some familiar substances found in our daily meals, namely capsaicin and catechin, we investigated age-related changes in taste preferences to capsaicin and catechin in young and old C57BL/6J mice using a 48-h two-bottle preference test. For the capsaicin stimuli, the mice showed avoidance behavior in a concentration-dependent manner. However, we observed that there was no significant difference in the preference ratio for capsaicin between young and old mice. For the catechin stimuli, although both age groups showed avoidance behavior in a concentration-dependent manner, the preference ratio in old mice showed significantly higher values than those in young mice. This suggests that catechin sensitivity is declined due to aging. Thus, we observed that catechin sensitivity decreases with age, but capsaicin sensitivity does not.