Can blueberries prevent dementia?

Drinking juice with a lot of antioxidants, for example from blueberries, can be beneficial in preventing dementia. New research at UiS will examine this in more detail by analyzing gut bacteria from elderly people who are at risk of developing Alzheimer's.

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Tre forskere i en lab.
Mark van der Giezen (left) at the laboratory in Måltidets hus.

Researchers at the University of Stavanger will try to find the effect of so-called anthocyanin supplements on the composition of the bacteria in the gut. Anthocyanins are antioxidants found in dark berries, such as blueberries. The main aim of the project is to investigate whether gut bacteria have an effect on cognition in a group of patients at risk of dementia.

As the global population continues to age, comes the increase in age-related conditions such as dementia. The aim of the new research project is to focus on prevention through diet. Anthocyanins (ACN) are so-called dietary flavonoids with strong antioxidant properties. They are mainly found in dark berries. ACN has anti-inflammatory properties and they are good for circulation. In addition, ACN has been shown to be an extremely promising candidate for dementia prevention as microbiome dysbiosis (the imbalance that can occur between good and bad bacteria in the gut flora) often affects people with dementia.

Redusert risiko

Professor Mark van der Giezen at Department of Chemistry, Bioscience and Environmental Engineering at UiS og Professor Dag Aarsland at King's College London are working together on the project, which has received NOK 200,000 in funding from Leon Jarner's memorial fund. A postdoctoral fellow at UiS takes care of the analyzes in the laboratory, while Aarsland will take a closer look at the cognitive abilities of the elderly. Patients will receive tablets with pure anthocyanins from wild blueberries.

"Anthocyanins have an effect on cognitive abilities. Studies involving consumption of ACN-rich juice showed protective effects in elderly people with memory impairment. Consumption of ACN-rich foods was associated with a reduced risk of Alzheimer's disease. We have collected the samples with intestinal bacteria, now we just need to analyze them," says Mark van der Giezen. He adds that they have a long-term plan for the research, although this project will only last a few months.

Van der Giezen believes there is a need for further research in the area.

"As we know that anthocyanins are promising in dementia prevention, this project was designed to fill knowledge gaps. In the study, elderly people at risk of dementia are given capsules that either contain pure ACN or identical placebo capsules," says van der Giezen.

Better cognition abilities

Dag Aarsland is a psychiatrist at King's College London and at Stavanger University Hospital. He also have 20 % position as Professor at UiS. Aarsland's part in the project is to take a closer look at the test group's cognition. Cognition is about the brain's ability to receive, process and express information. Dementia patients often have cognitive problems that include difficulties with remembering, planning and organizing, problems with time perception and understanding words.

"We have used computer-based tests that the participants complete at home, and look for changes in attention, mental pace and memory," says Aarsland.

Why there may be a connection between diet and the prevention of dementia, he explains in this way:

"We eventually know a lot about how different dietary elements affect the function of brain cells via various mechanisms, such as oxidative stress, inflammation, fat composition and the function of blood vessels. Some of the most interesting nutrients are called polyphenols. They are found in berries, fruit and vegetables with strong colours," says Aarsland.

Delays the disease

It is not enough to consume colorful food to keep the brain healthy. The patients must keep their brains active by reading books, solving crosswords and the like. And even if you consume so-called anthocyanins, you can still get dementia but the disease can be delayed by a couple of years.

"Looking at the gut bacteria of this group is something new that no one has done before," says van der Giezen.

Preliminary data have shown promising results. The researchers have collected cerebrospinal fluid (CSF), blood and stool samples at several points in time. Now they aim to analyze the gut microbiome in conjunction with all other available biomarkers. The researchers at UiS carry out analyzes both before and after the test group has eaten the blueberry tablets.

"This is a large survey. We have collected samples of gut bacteria from 100 people. A newly employed doctoral student takes a closer look at the good microbiome in the samples. If people have a certain composition of microbes in their gut that corresponds to good health, you can give bacterial samples from this group to other patients," explains Mark van der Giezen.

The analyzes are carried out in a laboratory at the Department of Chemistry, Bioscience and Environmental Engineering. The clinical examination is carried out at Stavanger University Hospital.

Text: Kjersti Riiber

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