ELDERLY people in care homes are being recruited for a new study examining whether diet affects Alzheimer's disease symptoms.

The research at Aberdeen University will explore for the first time potential links between the bacteria in a person's gut and dementia.

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Participants for the study, which is being funded by the Scottish Government and NHS Grampian's endowment fund, will be sought from local care homes.

Researchers want to compare the composition of bacteria in different people's digestive system to find out whether it influences cognitive decline, such memory problems and confusion, as well as the behavioural symptoms associated with Alzheimer's, such as aggressive outbursts.

The population of microbes, including bacteria, inside the human gut is known as the gut microbiota.

People who consume a varied diet high in fibre, fruit and vegetables are known to have a wider range of bacteria in their gut, and a diverse and balanced population of gut microbiota is known to be important in maintaining a strong immune system and aiding digestion.

Increasingly research has also discovered linked between gut health and obesity, with people who have a lower variety of bacteria or lacking specific types of bacteria being more prone to weight gain.

However, there is also increasing evidence that suggests the gut microbiota is a key link between specific nutrients and brain function.

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This first study aims to collect faecal samples from three groups of people – people with dementia and challenging behaviour; people with dementia without challenging behaviour; and a control group of people without dementia.

By studying these samples, the researchers hope to identify whether or not there are notable differences in the gut diversity of the three study groups.

If successful, this study could act as the first step towards establishing a link between diet and behaviour and possibly lead to future research looking at teasing out the complex relationship between diet, gut microbiota and challenging behaviour in Alzheimer’s disease.

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Professor Alex Johnstone from the University of Aberdeen’s Rowett Institute said: “It has become evident that there is a two-way communication between the gut microbiome and the brain.

"That relationship is not yet fully understood but the goal for us is to identify whether changes in diet can affect the clinical symptoms associated with dementia.

“This study is the first of its kind and could lead to the possibility of dietary intervention as a solution to prevent behavioural and psychosocial issues which are associated with adverse outcomes as well as distressing to people with dementia, their family and carers.

“We want to explore whether or not the gut-brain axis plays a key role in behavioural changes in dementia.”