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Why does the brain become more vulnerable to Alzheimer's disease with age?

A new study shows that a special protein plays a key role in the brain's cleansing system, which is important for keeping the brain healthy.

Cropped view of a senior man placing jigsaw puzzle pieces on a table.

“By the year 2100, one in four people will be over 65. This is an international concern, because there are serious health challenges associated with ageing, including Alzheimer's," says a researcher.

(Stock photo: Colourbox)

Ava Bosy Ava Bosy Communications adviser

Presented by: Presented by: University of Oslo

Published 15 August 2026 - 00:01

Alzheimer's disease is a common type of dementia. It is characterised by a progressive and permanent loss of nerve cells and the build-up of toxic proteins ('garbage') in the brain.

This breakdown causes memory loss, functional impairment, and personality changes.

In a new study, researchers found that the decline of a specific protein as we age may contribute to the loss of brain function in this disease.

“This study provides a new solid clue to explain why older people are more vulnerable to Alzheimer's disease, a scientific mystery that has lasted for decades,” says Evandro Fei Fang-Stavem.

He is a professor of gerontology and neuroscience at the University of Oslo. He also leads the Fang Lab, where students from ten countries study how ageing affects the body and contributes to age-related diseases.

Portrait photo of Evandro Fang-Stavem — Professor Evandro Fei Fang-Stavem.

We all have garbage trucks in our brains

Our brains constantly produce waste.

To keep our brains healthy, this waste needs to be removed regularly.

“We have small systems inside our cells that constantly find, package, and break down damaged or unnecessary proteins and other cellular components,” Fang-Stavem says. “These systems are our garbage trucks.”

The proteins are broken down into amino acids, which the body can reuse.

In scientific terms, this process is called autophagy.

In Alzheimer's disease, the garbage truck is destroyed

In Alzheimer's disease, the brain’s cleaning system does not work as well as it should.

Waste proteins build up and damage the brain. This makes it harder for brain cells to communicate, which can lead to problems with memory, thinking, and other brain functions.

This is something Fang-Stavem's group has researched extensively. Now they not only know which part of the garbage truck's engine is broken, but also how to fix it.

The key protein is called ULK1.

Fang-Stavem explains that ULK1 helps start and run the brain's cleansing system, ensuring that the cells stay healthy and have enough energy to function properly.

He now believes that a decline in ULK1 may be one reason why the ageing brain becomes more vulnerable to Alzheimer's disease.

A representation of autophagy in a brain cell, involving the protein ULK1.

The brain’s cleansing system becomes weaker with age

The study was based on a large amount of data, including brain fluid samples from people with Alzheimer's disease.

The researchers found that ULK1 plays an important role in controlling the brain's cleaning and recycling system. People with Alzheimer's had lower levels of ULK1 in their blood and brain fluid than people without cognitive impairments.

Portrait photo of Anne-Brita Knapskog — Professor Anne-Brita Knapskog.

“When ULK1 levels fall with age, this system may become less efficient, allowing Alzheimer's-related damage to build up,” says Anne-Brita Knapskog.

She is a professor at the University of Oslo's Department of Geriatric Medicine, and participated in the study.

There are a few medications available that can slow the progression of Alzheimer's disease, but their effects are limited.

“It's therefore urgent to develop new medications and therapies,” says Knapskog.

ULK1 is linked to long-term memory

The researchers also stuid brain fluid from healthy older people in Norway. They found that ULK1 levels decreased over a four-year period, even in people without cognitive impairment.

Fang-Stavem notes that ULK1 levels were significantly lower in Alzheimer’s patients than in the healthy controls.

"This reduction appeared to become more pronounced as the disease progressed,” he says.

The researchers also found reduced ULK1 in parts of the brain affected by Alzheimer’s. These regions are important for creating, storing, and accessing long-term memories, as well as for attention and self-control.

An ageing global population

Old age is the most significant risk factor for developing Alzheimer's disease.

The older we get, the greater the risk of developing dementia.

The global population of older adults is expected to increase significantly over the next few decades, something which worries Fang-Stavem.

“By the year 2100, one in four living people will be over 65. This represents an international concern, because there are serious health and socioeconomic challenges associated with ageing, including Alzheimer’s,” he says.

On the hunt for natural substances

Fang-Stavem's research group is looking for natural substances that could help alleviate symptoms of the disease.

They have already identified promising molecules from traditional Chinese medicine and found that a molecule from passion fruit might slow the development of the disease.

The researchers are now testing one of these discoveries in people with Alzheimer’s. A natural compound found in pomegranate showed promising potential in reducing the harmful waste that builds up in the brain.

“We’re excited to move the lab discovery to the clinic,” says Fang-Stavem.

But the researcher notes that more studies are needed before ULK1 can safely be used as a measurement for disease and as a target for treatment.

“Although we are cautiously optimistic that increasing the activity of ULK1 can become a new target for developing drugs against Alzheimer's, more studies are needed to validate our findings,” he says.