Startling Discovery: Menthol’s Connection to Alzheimer’s in Mice

In an intriguing study conducted in 2023, researchers discovered an unexpected correlation: the inhalation of menthol appears to ameliorate cognitive impairments in murine models afflicted with Alzheimer’s disease. This chemical compound seemingly mitigates some of the neurodegenerative effects typically associated with the ailment.

Specifically, a marked reduction in the levels of interleukin-1-beta (IL-1?) protein was observed. IL-1? plays a crucial role in modulating the body’s inflammatory response—a mechanism that can provide natural defense yet, if inadequately regulated, may inflict substantial harm.

The investigative team, whose findings were disseminated in April 2023, posits that this research elucidates the potential of utilizing olfactory stimuli as therapeutic interventions for Alzheimer’s. By deciphering the specific odors that trigger distinct cerebral and immunological responses, we could harness their properties to enhance health outcomes.

“Our focus has been the interplay between the olfactory system and both the immune and central nervous systems, leading us to confirm that menthol acts as an immunostimulatory odor in animal models,” stated immunologist Juan José Lasarte from the Center for Applied Medical Research (CIMA) in Spain following the announcement of these results.

Remarkably, persistent exposure to menthol over six months not only halted cognitive deterioration in Alzheimer’s-affected mice but also enhanced cognitive function in healthy young specimens.

Having previously noted menthol’s capacity to augment immune responses in mice, the current study compellingly demonstrated its ability to enhance cognitive faculties through a variety of rigorous laboratory assessments.

The prolonged menthol exposure successfully preserved cognitive and memory functions in the Alzheimer’s models and appeared to restore IL-1? levels to a physiologically safe range within the cerebral context.

When researchers strategically diminished T regulatory (Treg) cells, known for modulating immune responses, some analogous outcomes emerged, indicating a potential pathway for future therapeutic approaches.

“Both menthol exposure and Treg cell blockade induced a reduction in IL-1?, a protein potentially implicated in cognitive decline in these models,” remarked neuroscientist Ana Garcia-Osta from CIMA.

“Moreover, the targeted inhibition of this protein utilizing pharmaceuticals typically prescribed for certain autoimmunological disorders also enhanced cognitive efficacy in both healthy and Alzheimer’s-affected mice.”

Extensive research has elucidated numerous associations between olfactory stimuli and both the immune and nervous systems; however, the intricate nature of these relationships continues to pose challenges for comprehensive understanding. The olfactory system undoubtedly exerts substantial influence over cerebral activity.

Indeed, central nervous system disorders—such as Alzheimer’s, Parkinson’s, and schizophrenia—are frequently accompanied by olfactory deficits. While this research provides promising data, further investigations in human subjects remain imperative.

“This study constitutes a pivotal stride in elucidating the nexus between the immune system, central nervous system, and olfactory stimuli,” asserted immunologist Noelia Casares from CIMA. “The findings suggest that odors and immune modulators may play a significant role in the prophylaxis and management of Alzheimer’s and related neurological conditions.”

The comprehensive research is published in Frontiers in Immunology.

A previous iteration of this article first appeared in May 2023.