Potential Role for Diet in Mediating the Association of Olfactory Dysfunction and Cognitive Decline: A Nationally Representative Study

In the context of a growing body of evidence associating olfactory dysfunction (OD) with cognitive decline, this cross-sectional study used data from the 2013–2014 National Health and Nutrition Examination Survey (NHANES) sample in order to explore the role of dietary intake in this association. Leveraging a nationally representative sample of U.S. adults aged 60 years and older, this study analyzed dietary patterns using exploratory factor analysis. OD was categorized based on the NHANES Pocket Smell Test, and cognitive function was measured with a battery of tests. Survey-weighted multivariable regressions and causal mediation analysis were used to examine the relationship between dietary patterns, OD, and cognitive function. Results indicated that a poor adherence to a diet rich in monounsaturated fats (MUFAs) and polyunsaturated fats (PUFAs) was independently associated with both cognitive and olfactory dysfunctions, after adjusting for sociodemographic and health factors. Moreover, the relationship between OD and cognitive decline was found to be partly mediated by adherence to such a diet. This study proposes a potential link between diet, olfactory function, and cognitive decline, highlighting the role of nutritional interventions in mitigating cognitive decline, particularly in individuals with olfactory impairment.