In a recent study published within the journal Nutrients, a team of researchers in Australia conducted a review to know the species-level diversity of the gut microbiome and its role within the pathology of Alzheimer’s disease. Additionally they investigated how confounding elements akin to prebiotics and probiotics and eating regimen influence the assorted stages of Alzheimer’s disease.

Study: The Role of Eating regimen and Gut Microbiota in Alzheimer’s Disease. Image Credit: Design_Cells / Shutterstock

Background

Alzheimer’s disease is a neurodegenerative disease characterised by progressive cognitive impairments that have an effect on day by day life and functioning. These cognitive impairments affect abilities akin to decision-making, memory, problem-solving, considering, and mobility, often accompanied by drastic personality changes. The cognitive decline is attributed to the formation of amyloid-beta plaques and the hyperphosphorylation of tau neurofibrillary tangles, which also lead to inflammation.

Recent studies have also found that the gut microbiome-brain axis plays an important role in influencing the danger of mental health disorders akin to depression and various neurodegenerative diseases, including Alzheimer’s disease. Individuals with mild cognitive impairments and Alzheimer’s disease have been found to have lower diversity indices for gut microbiota as in comparison with healthy controls.

Various aspects akin to age, genetics, eating regimen, and antibiotic usage are known to affect the gut microbiome, and understanding the interactions between these aspects, the gut microbiome, and its potential links to Alzheimer’s disease could assist in the early identification of people prone to developing the disease.

Alzheimer’s disease and gut microbiota

In the current review, the researchers discussed the incidence rate of Alzheimer’s disease worldwide and in Australia. Additionally they make clear the incidence rates of dementia and young-onset dementia and the mortality risk related to dementia. Studies from the USA (U.S.) have shown that the annual health costs related to Alzheimer’s disease and dementia are over 600 billion U.S. dollars, and it is anticipated to extend significantly by 2030.

The review also covered what is thought about Alzheimer’s disease pathology, including detailed discussions concerning the formation of amyloid-beta plaques within the brain, starting with the orbitofrontal, temporal, and basal neocortex regions and eventually spreading to the amygdala, basal ganglia, hippocampus, and diencephalon.

Quite a few hypotheses have been put forth to clarify the mechanisms through which amyloid-beta peptides and tau neurofibrillary tangles contribute to the neurodegeneration in Alzheimer’s disease, akin to hyperphosphorylation of tau neurofibrillary tangles and the amyloid cascade. The review expanded on these hypotheses, in addition to other potential mechanisms akin to mitochondrial dysfunction, oxidative stress, and neuroinflammation.

Studies investigating the link between gut microbiota and Alzheimer’s disease have reported an association between specific gut microbes and ranging levels of Alzheimer’s disease biomarkers within the cerebrospinal fluid. Other studies have found a link between the composition of the gut microbiome and levels of amyloid peptide within the brain. The researchers presented an in-depth discussion of the present research on associations between specific gut microbes and various pathological points of Alzheimer’s disease.

Eating regimen, gut microbiome, and Alzheimer’s disease

The proven fact that eating regimen plays a pivotal role in influencing gut microbiome composition and variety is a well-supported finding. The composition of the gut microbiome can be modified through specific dietary patterns and the consumption of assorted supplements, which might, in turn, have an effect on the gut-brain axis and influence Alzheimer’s disease pathology.

The review extensively discussed the role of assorted dietary components akin to protein, fiber, fat, and polyphenols and various dietary patterns in influencing the gut microbiome environment and composition. It also reported on studies that found significant improvements within the cognitive function of Alzheimer’s disease patients after specific dietary patterns akin to the ketogenic eating regimen, Mediterranean eating regimen, and diets targeting hypertension and neurodegeneration.

The researchers also found that although the body of research on the usage of pre and probiotics supplements as therapeutic options for Alzheimer’s disease remains to be limited, various studies have reported that the usage of pre and probiotics and combos of the 2 can modify Alzheimer’s disease progression and related neuropathology.

Conclusions

To summarize, the review comprehensively examines the present research on the interplay between eating regimen, gut microbiota, and Alzheimer’s disease pathology. The findings suggest that gut dysbiosis is strongly linked to the progression of the pathology of Alzheimer’s disease and presents a possible avenue for non-invasive therapy and risk modification.