Exploring the Link Between Gut Bacteria and Alzheimer's Disease: an insight in the current evidence
“The future of Alzheimer's prevention and treatment might involve targeting the gut.”
Recent research by Grabrucker et al. suggests that changes in the bacteria in the gut may play a role in the development of Alzheimer's disease.
What were the findings?
In a study, researchers transferred fecal material from Alzheimer's patients and healthy individuals into rats without gut bacteria. The rats that received material from Alzheimer's patients showed behaviour problems related to the hippocampus, a brain region important for memory.
The study found that Alzheimer's patients had fewer beneficial bacteria associated with healthy aging (Coprococcus), and more harmful bacteria (Desulfovibrio), which correlated with lower cognitive scores. Interestingly, cognitive decline in rats was not linked to the presence of amyloid plaques in the brain, suggesting independent factors at play.
What does this mean for the future Alzheimer’s prevention treatment?
This research indicates that imbalances in gut bacteria may be a significant factor in the development of Alzheimer's. Other studies also support this idea, showing that Alzheimer's patients have more gut bacteria imbalances compared to healthy individuals. These imbalances can contribute to processes like amyloid-beta aggregation, inflammation, oxidative stress, and insulin resistance, all key mechanisms involved in the development and progression of Alzheimer's.
The future of Alzheimer's prevention and treatment might involve targeting the gut. An animal study found that transferring fecal material from healthy mice to mice with Alzheimer's improved cognitive function. However, more research is needed to confirm these findings in humans. Some scientists propose personalized diets and interventions to modulate the gut microbiome as potential preventative and treatment measures for Alzheimer's. Studies over the past few years suggest that adhering to a healthy diet, like the MIND diet, may reduce the risk of Alzheimer's. The MIND diet involves consuming recommended amounts of various food items like fruits, vegetables, fish, meat, dairy and more. Other research supports the idea that following such diets can improve cognitive function and lower the incidence of Alzheimer's.
In conclusion, as our understanding of the connection between the gut and Alzheimer's grows, nutrition is becoming a crucial focus in research and may play a significant role in future treatments for the disease.
Sources:
Grabrucker, S., Marizzoni, M., Silajdžić, E., Lopizzo, N., Mombelli, E., Nicolas, S., Dohm-Hansen, S., Scassellati, C., Vito Moretti, D., Rosa, M., Hoffmann, K., Cryan, J. F., O’Leary, O. F., English, J. A., Lavelle, A., O’Neill, C., Thuret, S., Cattaneo, A., Nolan, Y. M. (2023) ‘Microbiota from Alzheimer’s patients induce deficits in cognition and hippocampal neurogenesis’, Brain, 146 (12), pp. 4916–4934. Available at: https://doi.org/10.1093/brain/awad303
Morris, M. C., Tangney, C. C., Wang, Y., Sacks, F. M., Bennett, D. A., & Aggarwal, N. T. (2015) ‘MIND diet associated with reduced incidence of Alzheimer's disease’, Alzheimer's & dementia : the journal of the Alzheimer's Association, 11(9), pp. 1007–1014. Available at: https://doi.org/10.1016/j.jalz.2014.11.009
Morris, M. C., Tangney, C. C., Wang, Y., Sacks, F. M., Barnes, L. L., Bennett, D. A., & Aggarwal, N. T. (2015) ‘MIND diet slows cognitive decline with aging’, Alzheimer's & dementia : the journal of the Alzheimer's Association, 11(9), pp. 1015–1022. Available at: https://doi.org/10.1016/j.jalz.2015.04.011
