Adherence to healthy plant-rich diets is associated with better olfactory function in the general population - Findings from the Cooperative Health Research in South Tyrol (CHRIS) study

Olfactory dysfunction is associated with increased all-cause mortality among older adults and an early indicator of brain aging. Different lifestyle factors and health conditions determine olfactory function, however, there is limited knowledge on the association with diet quality. We investigated the association between various dietary patterns and olfactory function, as well as hyposmia, in a general population study using cross-sectional data from 6690 participants of the Cooperative Health Research in South Tyrol (CHRIS) study. We assessed self-reported dietary intake through the GA2LEN semi-quantitative Food Frequency questionnaire, which was used to derive five established dietary pattern indices (Alternate Healthy Eating Index 2010, Mediterranean diet index, Plant-based dietary index, Healthy Plant-based dietary index, Unhealthy plant-based dietary index), as well as various food groups. Olfactory function was measured through the Sniffin'Sticks odor identification test, which allowed us to determine hyposmia with a score ≤12/16. Multivariable ordinal and logistic regression models were fitted to investigate associations between each dietary pattern, food groups, and olfaction. Higher adherence to all healthy dietary patterns was associated with both, better olfactory function and lower rates of hyposmia, while the opposite was observed for the unhealthy plant-based diet. Specifically, higher consumption of fruits, vegetables, coffee, and tea was beneficially associated with both outcomes. Higher adherence to healthy dietary patterns that are rich in plant-based foods was associated with better olfactory function and lower rates of hyposmia.