Could Your Daily Diet Shape Your Sense of Smell? What a New Population Study Found
A growing body of scientific inquiry continues to examine how lifestyle factors influence sensory perception, prompting researchers to explore the connection between daily eating habits and olfactory function. While previous investigations have largely focused on how diet impacts metabolic or cardiovascular health, a study published in the journal Chemical Senses has shifted attention toward how different dietary patterns relate to a person ability to identify odors.
Understanding Olfactory Function and Dietary Patterns
Researchers note that olfactory dysfunction affects a notable portion of the population, with an estimated prevalence of roughly 22%. Reduced sensory perception in older adults has previously been linked in published literature to a lower quality of life, malnutrition, and higher all-cause mortality rates. Major established causes of olfactory issues typically include sinonasal disease, upper respiratory tract infections, and traumatic brain injuries.
To investigate whether dietary choices also play a role, investigators turned to population-based data. They analyzed information from the Cooperative Health Research in South Tyrol study, an extensive Italian cohort that gathered lifestyle, health, and demographic details alongside biological samples from nearly 13,400 adult participants at baseline.
How the Investigation Was Conducted
For the published analysis, the team evaluated data from 6,690 participants with a mean age of 44.5 years, where 54% of the cohort identified as female and 55% as non-smokers. Olfactory function was measured directly using the validated 16-item Sniffin Sticks odor identification test. Individuals who successfully identified 12 or fewer out of the 16 target odors were classified as having hyposmia, representing a reduced sense of smell.
Dietary intake over the preceding year was captured using a food frequency questionnaire. From this dietary data, researchers calculated several established indices:
- The Mediterranean diet index
- The Alternate Healthy Eating Index 2010
- Overall plant-based diet index
- Healthful plant-based diet index
- Unhealthful plant-based diet index
The statistical models were adjusted for various potential confounding factors, including sex, age, education, body mass index, smoking status, hypertension, and total energy intake. Additional sensitivity analyses factored in positive screenings for Parkinson disease and cognitive impairment.
Key Findings and Associations
The cross-sectional analysis identified modest associations between certain eating patterns and olfactory performance. Greater adherence to healthier dietary patterns—such as the Alternate Healthy Eating Index, the Mediterranean diet index, and healthful plant-based indices—was modestly associated with higher odds of falling into a better olfactory function category. Conversely, an inverse association was observed for unhealthful plant-based diet patterns, where higher scores corresponded to worse odor identification scores.
Furthermore, higher consumption of fruits and vegetables, as well as reported intake of tea, coffee, and alcoholic beverages, showed associations with better odor identification and lower odds of hyposmia. However, study authors and health experts emphasize important nuances regarding these findings.
Important Limitations and Context
The researchers explicitly noted several limitations inherent to the study design. Because the research utilized a cross-sectional approach, it cannot establish causation. It remains unclear whether dietary habits actively shape olfactory function or if an impaired sense of smell alters an individual food preferences and dietary choices over time.
Additionally, dietary intake relied on self-reported questionnaires, and the sensory testing specifically measured odor identification rather than every dimension of olfaction. Regarding alcohol consumption, the authors cautioned that these observational associations do not establish that alcohol improves smell, aligning with public health recommendations indicating that no level of alcohol consumption is considered entirely safe. Further longitudinal research is required to fully understand the complex relationship between nutrition and sensory health.
