Gut bacteria linked to Alzheimer’s disease

Studying the composition of gut bacteria is of great interest to scientists because through the interaction between the immune system, the intestinal mucosa and our diet, they have a major impact our health. 

The composition of our gut microbiota composition does change and depends on which bacteria we receive at birth, our genes and our diet.

In this study, researchers found the composition of bacteria in the gut is different between healthy mice and mice with Alzheimer’s disease. 

Testing the relationship between intestinal bacteria and Alzheimer’s disease further, researchers studied Alzheimer’s disease in mice that completely lacked bacteria. 

They found these mice had a significantly smaller amount of beta-amyloid plaque in the brain. Beta-amyloid plaques have long been associated with Alzheimer’s disease.

Finally, to clarify the link between gut bacteria and Alzheimer’s disease, researchers transferred intestinal bacteria from diseased mice to germ-free mice; these mice then developed more beta-amyloid plaques in the brain compared to if they had received bacteria from healthy mice.

“Our study is unique as it shows a direct causal link between gut bacteria and Alzheimer’s disease. It was striking that the mice which completely lacked bacteria developed much less plaque in the brain,” says researcher Frida Fåk Hållenius, at the Food for Health Science Centre.

Researchers also believe these results could open up the door to new opportunities for preventing and treating Alzheimer’s disease.

“The results mean that we can now begin researching ways to prevent the disease and delay the onset,” says Dr Fåk Hållenius. “We consider this to be a major breakthrough as we used to only be able to give symptom-relieving antiretroviral drugs.”