Loss of olfactory function is a common issue in aging individuals, affecting quality of life and potentially contributing to cognitive decline and depressive symptoms. Research has suggested that olfactory training (OT), which involves regular exposure to specific odors, can improve smell function. The study “Olfactory Training with Older People” by Wegener, Croy, Hähner, and Hummel aimed to explore the benefits of OT in older adults, particularly in relation to olfactory function, cognitive ability, and emotional well-being.

Conducted at the Smell and Taste Clinic at TU Dresden, this controlled, unblinded, longitudinal study involved 91 participants aged 50 to 84 years. Participants were randomly assigned to two groups: the OT group (60 participants), who performed olfactory training for five months, and a control group (31 participants), who completed daily Sudoku puzzles instead. Both groups were tested at the beginning and end of the study to assess their olfactory abilities, cognitive function, and psychological well-being.

The OT group was instructed to smell four specific odors—lime, cloves, eucalyptus, and rose—twice daily for five months. To monitor compliance, participants recorded their olfactory experiences in a “smell diary.” The control group engaged in Sudoku puzzles for the same duration, serving as an active cognitive control to ensure that any improvements were due to olfactory training rather than general mental stimulation.

After five months, the results demonstrated a significant improvement in olfactory function in the OT group. The improvement was particularly evident in odor threshold detection and discrimination ability, though odor identification remained unchanged. Approximately 20% of the OT group improved their olfactory function by at least 5.5 points, compared to only 10% in the control group. These findings align with previous research indicating that repeated exposure to odors can enhance olfactory sensitivity over time.

Beyond improvements in the sense of smell, olfactory training also positively influenced cognitive function. While general cognitive performance remained stable, verbal fluency improved significantly in the OT group. This effect was especially pronounced in semantic-categorical fluency tasks, where participants were required to list words related to a specific category. The control group did not exhibit similar improvements, suggesting that OT may enhance verbal processing abilities.

A key finding of the study was the impact of olfactory training on emotional well-being. Participants with mild depressive symptoms at the beginning of the study showed a reduction in depressive scores after completing the olfactory training, while no such improvement was observed in the control group. These findings suggest that olfactory training may offer a non-invasive, cost-effective approach to enhancing mood in older individuals, potentially due to its engagement with brain regions involved in emotion regulation, such as the amygdala and orbitofrontal cortex.

Despite these promising results, the study had several limitations. The sample was predominantly female, which may limit the generalizability of the findings. Additionally, the study relied on self-reported compliance with olfactory training, raising the possibility that some participants may not have adhered strictly to the protocol. Another limitation was the small number of participants with depressive symptoms, making it difficult to draw strong conclusions about the effect of OT on depression. Future research could address these limitations by including a more diverse participant pool, longer follow-up periods, and objective measures of compliance.

Overall, the study supports the hypothesis that olfactory training is a simple and inexpensive method to improve olfactory function, verbal fluency, and emotional well-being in older adults. While additional research is needed to further explore the long-term benefits, these findings highlight the potential of olfactory training as a valuable tool for maintaining cognitive and emotional health in aging populations.