In a recent study published in the journal NutrientsA team of Australian researchers conducted a review to understand the species-level diversity of the gut microbiome and its role in Alzheimer’s disease pathology. They also looked at how confounding factors such as prebiotics and probiotics and diet affect various stages of Alzheimer’s disease.
Study: The role of diet and gut microbiota in Alzheimer’s disease. Image source: Design_Cells/Shutterstock
Alzheimer’s disease is a neurodegenerative disease characterized by progressive cognitive impairment that affects daily life and functioning. These cognitive impairments affect the ability to make decisions, memory, problem-solving, thinking, and action, and are often accompanied by dramatic personality changes. Cognitive decline results from the formation of beta-amyloid plaques and hyperphosphorylation of tau neurofibrillary tangles, which also lead to inflammation.
Recent research has also found that the gut microbiome-brain axis plays a crucial role in influencing the risk of mental health conditions such as depression and various neurodegenerative diseases, including Alzheimer’s disease. Studies have found that individuals with mild cognitive impairment and Alzheimer’s disease have lower gut microbiota diversity indices compared to healthy controls.
Several factors such as age, genetics, diet, and antibiotic use are known to influence the gut microbiome, and understanding the interactions between these factors, the gut microbiome, and their potential link to Alzheimer’s disease may help early Identify individuals at risk of developing this disease.
Alzheimer’s disease and the gut microbiome
In this review, researchers discuss the incidence of Alzheimer’s disease globally and in Australia. They also reveal the incidence of dementia and dementia praecox and the risk of dementia-related death. Research in the United States shows that annual health costs related to Alzheimer’s disease and dementia exceed $600 billion and are expected to increase significantly by 2030.
The review also covers what is known about Alzheimer’s disease pathology, including a detailed discussion of amyloid plaque formation in the brain, starting in the orbitofrontal, temporal, and basal neocortical regions and eventually spreading to the amygdala nuclei, basal ganglia, hippocampus, and diencephalon.
Many hypotheses have been proposed to explain the mechanisms by which amyloid-beta peptides and tau neurofibrillary tangles contribute to neurodegeneration in Alzheimer’s disease, such as hyperphosphorylation of tau neurofibrillary tangles and the amyloid cascade. This review expands on these hypotheses as well as other potential mechanisms such as mitochondrial dysfunction, oxidative stress, and neuroinflammation.
Studies investigating the link between the gut microbiome and Alzheimer’s disease have reported associations between specific gut microbes and varying levels of Alzheimer’s disease biomarkers in cerebrospinal fluid. Other studies have found links between the composition of the gut microbiome and levels of amyloid peptides in the brain. The researchers provide an in-depth discussion of existing research linking specific gut microbes to various pathological aspects of Alzheimer’s disease.
Diet, Gut Microbiome, and Alzheimer’s Disease
It is well supported that diet plays a key role in influencing gut microbiome composition and diversity. The composition of the gut microbiota can also be altered through specific dietary patterns and consumption of various supplements, which in turn can influence the gut-brain axis and influence Alzheimer’s disease pathology.
This review extensively discusses the role of various dietary components (e.g., protein, fiber, fat, and polyphenols) and various dietary patterns in influencing the gut microbiome environment and composition. It also reports on studies that have found significant improvements in cognitive function in people with Alzheimer’s disease following specific dietary patterns, such as the ketogenic diet, the Mediterranean diet, and diets for hypertension and neurodegenerative diseases. improve.
The researchers also found that while research on the use of probiotics and probiotic supplements as treatment options for Alzheimer’s disease remains limited, various studies report that the use of probiotics and probiotics, as well as a combination of the two, can change Alzheimer’s disease. Progression of Heimer’s disease and associated neuropathology.
In summary, this review provides a comprehensive look at existing research on the interactions between diet, gut microbiota, and Alzheimer’s disease pathology. The findings indicate that intestinal dysbiosis is closely associated with the pathological progression of Alzheimer’s disease and provide potential avenues for non-invasive treatment and risk reduction.
- Dissanayaka, DM Sithara, Jayasena, V., Rainey-Smith, SR, Martins, RN, & Fernando, WMADB (2024). The role of diet and gut microbiota in Alzheimer’s disease. Nutrients, 16(3). DOI 10.3390/nu16030412, https://www.mdpi.com/2072-6643/16/3/412