The key to stopping Alzheimer's may lie in your GUT - NOT your brain, experts now say

The key to stopping dementia may lie in the gut rather than the brain, new research suggests.

Decades of studies from around the world costing billions of pounds have so far failed to find a way to tackle the memory-robbing disease.

But the gut “represents an alternative target that may be easier to influence with medication or dietary changes,” experts say.

A series of experiments linking the gut to the development of Alzheimer's disease are to be presented at a medical conference today.

It will be shown how the microbiomes – the bacterial community in the intestines – of patients with this disease can differ massively from those without the disorder.

Another study found that rodents given fecal transplants directly from Alzheimer's patients performed worse on memory tests.

A third study found that brain stem cells treated with blood from patients with the condition were less able to grow new nerve cells.

Theoretically, patients' gut bacteria influence the level of inflammation in the body, which then affects the brain through the blood supply.

Inflammation is considered a key factor in the development of Alzheimer's.

The disease is the most common form of dementia,and one of the leading causes of death in the UK.

Charities estimate that around 900,000 people in the UK and 5 million in the US live with the disorder, with this number growing every year the longer we live.

Alzheimer's is thought to be caused by aFormation of plaque in the brain, which eventually leads to the death of brain cells.

There is currently no cure, but there are already medications that help relieve symptoms by helping nerve cells communicate.

There is hope that treatments could be developed that target the gut, which could then improve the condition in the brain.

Dr. Edina Silajdžić, a neuroscientist from King's College London who was involved in analyzing samples from Alzheimer's patients, said: "Most people are surprised that their gut bacteria could have an impact on the health of their brain.

“But the evidence is mounting – and we are building an understanding of how this comes about.

“Our gut bacteria can influence the level of inflammation in our bodies, and we know that inflammation is a major contributor to Alzheimer’s.”

She was behind King's research, which compared the microbiomes of 68 people with Alzheimer's and a similar number of people without Alzheimer's.

Blood and stool samples were taken from all participants and analyzed in a biological laboratory in Italy.

These tests showed that people with Alzheimer's had a distinct microbiome as well as more inflammatory markers.

Follow-up experiments on the treatment of brain stem cells with the blood of people with Alzheimer's.

These were found to be less able to grow new nerve cells than controls treated with blood from people without the disease.

Dr. Silajdžić said: “This leads us to believe that inflammation related to gut bacteria can affect the brain through the blood.”

Her team's study will be presented today at the Alzheimer's Research UK 2022 Conference in Brighton.

Another research paper revealed looked at the effects of Alzheimer's microbiome on rats.

Stool samples were taken from people with and without Alzheimer's and transplanted into the rodents' intestines.

Professor Yvonne Nolan, a neuroscientist also from King's, who analyzed the results said there were key differences in how rats performed on memory tests depending on the sample they received.

"We found that rats with gut bacteria from people with Alzheimer's performed worse on memory tests," she said.

They also didn't grow as many new nerve cells in areas of the brain associated with memory and had higher levels of inflammation.

She added that this finding suggests that Alzheimer's may be caused, at least in part, by abnormalities in the gastrointestinal tract.

Previous studies have shown that gut bacteria may be involved in a variety of brain functions, from appetite control to mental illnesses such as depression and anxiety.

Professor Nolan said that, unlike the brain, the gut could represent an alternative and simpler part of the body to target for potential Alzheimer's treatments.

"While it currently proves difficult to directly target Alzheimer's processes in the brain, the gut may represent an alternative target that may be easier to influence with medication or dietary changes," she said.

Neither series of research was peer-reviewed prior to the conference.

Responding to the new studies, Alzheimer's Research UK Research Director Dr. Susan Kohlhaas that they provide a good basis for further work on the relationship between intestinal bacteria and Alzheimer's.

"The summary of these results shows differences in the composition of gut bacteria between people with and without dementia and suggests that the microbiome may drive changes associated with Alzheimer's disease," she said.

“Future research needs to build on these findings so we can understand how gut health fits into the broader picture of genetic and lifestyle factors that impact a person’s risk of dementia.”

She added that in the meantime, people should actively try to keep their brain healthy as they age to reduce their risk of developing Alzheimer's.

“Current evidence suggests that we should stay physically fit, eat a balanced diet, maintain a healthy weight, not smoke, drink only within recommended limits and keep blood pressure and cholesterol under control,” she said.