Research from Iowa State University has suggested that keeping your brain active into older age can help safeguard against the memory loss associated with conditions like Alzheimer's disease.
The study, published in the journal Brain, Behavior and Immunity, identified a protein that is essential for building memories. The research team hope that measuring levels of this protein - neuronal pentraxin-2 (NPTX2) - could help better judge how much memory loss will occur when a patient is diagnosed with Alzheimer's disease.
Auriel Willette, an assistant professor of food science and human nutrition, and Ashley Swanson, a graduate research assistant, said the findings suggest a link between brain activity and NPTX2.
The study found a correlation between higher levels of NPTX2 and better memory and more brain volume, with lower levels of this key protein being associated with poorer memory and less volume.
Dr Swanson said NPTX2 seems to have the ability to protect the brain, with people with high levels of it having less brain atrophy and better memory.
It is hoped the new findings will help track and monitor Alzheimer's disease as it progresses. However, researchers are now looking at ways to boost levels of NPTX2 to see whether this can have a memory-protecting effect.
Dr Swanson and her team found that participants who had stayed in education longer had higher levels of NPTX2. The study also revealed that those who had complex jobs or were mentally and socially active could see the same benefits as those with better education.
"You're keeping the machinery going," Ms Willette said. "It makes sense that the more time spent intensely focused on learning, the more your brain is trained to process information and that doesn't go away. That intense kind of learning seems to make your brain stronger."
The team used information collected in the Alzheimer's Disease Neuroimaging Initiative to assess which parts of the immune system are most relevant to tracking Alzheimer's disease progression.
Using data from 285 older adults, they found that two proteins - NPTX2 and Chitinase-3-like-protein-1 (C3LP1) - were consistently able to predict aspects of the disease.
The team then looked at memory performance at the start of the study, and then six months, one year and two years later.
Expecting C3LP1 - which is linked to brain inflammation - to be a stronger indicator for Alzheimer's, the researchers were surprised when it was NPTX2 that proved to be consistently significant over the two-year analysis.
"We see this as a promising biomarker that affects a lot of key aspects of Alzheimer's disease," Dr Swanson said. "It's a revolutionary approach and we're looking at it in a more holistic way, rather than a reductionist viewpoint, to understand how the immune system and brain are connected."