Changes in human microbiome precede Alzheimer’s cognitive declines

While pinpointing the exact causes of Alzheimer’s remains a major research challenge, they likely involve a combination of genetic, environmental, and lifestyle factors.

Bacteria in the gut. Photo: Donny Bliss/NIH

A new study elucidates the role of another likely culprit that you may not have considered: the human gut microbiome, the trillions of diverse bacteria and other microbes that live primarily in our intestines.

Earlier studies showed that the gut microbiomes of people with symptomatic Alzheimer’s differ from those of healthy people with normal cognition.

What’s exciting about this finding is it raises the possibility that doctors one day could test a patient’s stool sample to determine if what’s present from their gut microbiome correlates with greater early risk for Alzheimer’s dementia.

Such a test would help doctors detect Alzheimer’s earlier and intervene sooner to slow or ideally even halt its advance.

The new findings come from a research team led by Gautam Dantas and Beau Ances, Washington University School of Medicine in St. Louis.

The researchers found that those with preclinical Alzheimer’s had markedly different assemblages of gut bacteria. Their microbiomes differed in many of the bacterial species present.

Those species-level differences also point to differences in the way their microbiomes would be expected to function at a metabolic level.

These microbiome changes were observed even though the individuals didn’t seem to have any apparent differences in their diets.

The team also found that the microbiome changes correlated with beta-amyloid and tau levels in the brain. But they did not find any relationship to degenerative changes in the brain, which tend to happen later in people with Alzheimer’s.

The team is now conducting a five-year study that will follow volunteers to get a better handle on whether the differences observed in the gut microbiome are a cause or a consequence of the brain changes seen in Alzheimer’s. (National Institutes of Health)

YOU MAY ALSO LIKE

Biological clocks of people and malaria parasites tick in tune

Research could pave the way to new anti-malarials that work by 'jet-lagging' the parasites that cause the disease.

Omega-3 fatty acids appear promising for maintaining lung health

Omega-3 fatty acids, which are abundant in fish and fish oil supplements, appear promising for maintaining lung health.

Scientists discover clues to aging and healing from a squishy sea creature

A relative of jellyfish and corals regrows its entire body with help from “aging” cells.

Intraocular corticosteroids best for treating complications of chronic inflammatory eye condition

Repeat treatment with corticosteroid injections improved vision in people with persistent or recurrent uveitis-related macular edema better than two other therapies.

DNA discovery highlights how we maintain healthy blood sugar levels after meals

A study of the DNA of more than 55,000 people worldwide has shed light on how we maintain healthy blood sugar levels after we have eaten, with implications for our understanding of how the process goes wrong in type 2 diabetes.

Mediterranean Diet's Cellular Benefits Unveiled in New Study

A new study led by Stanford School of Medicine researchers has shed light on one of the cellular mechanisms behind the health benefits of the Mediterranean diet, which is known to promote longevity and overall well-being compared to diets high in fast food, meat, and dairy.