Most people assume that the health of their brain depends mainly on how many birthdays they have celebrated.
While growing older certainly changes the brain, a large new study suggests there is another important factor that works independently of age: metabolic health.
This means two people of very different ages could have brains that look surprisingly similar if one has excellent metabolic health and the other does not.
The research, published in PLOS Biology, analyzed more than 3,000 brain scans and found that the brain appears to age through two separate biological pathways. One pathway reflects the normal aging process. The other is linked to metabolic health, which includes factors such as body weight, blood pressure, cholesterol, and blood sugar.
The brain is the body’s control center. It depends on a constant supply of oxygen and nutrients delivered through the bloodstream. Healthy blood vessels allow brain cells to work properly, while poor blood flow can reduce memory, thinking, and concentration over time.
Scientists have long known that getting older causes changes in the brain. The outer layer of the brain gradually becomes thinner, and blood vessels become less efficient. These natural changes can slow thinking and increase the risk of memory problems.
However, researchers wanted to know whether common health measures collected during routine medical visits could also reveal information about brain health.
To answer this question, researchers combined health information with advanced MRI brain scans. They studied 597 adults between 36 and 100 years old from the Human Connectome Project-Ageing and then tested their findings in another 3,013 adults from the UK Biobank, aged 51 to 83.
Using advanced statistical methods, they compared routine health markers such as body mass index, blood pressure, cholesterol, and glucose measures with detailed brain scans that measured brain structure, activity, and blood flow.
The analysis revealed two distinct patterns. The first represented normal aging and was linked to thinning of brain tissue and other structural changes. The second reflected metabolic health and mainly affected blood flow to the brain rather than its structure.
People with poorer metabolic health generally had lower cerebral perfusion, meaning less blood reached their brain tissue. They also performed worse on tests measuring cognitive flexibility, the ability to switch between tasks, solve new problems, and adapt to changing situations. Interestingly, this relationship appeared stronger in women than in men.
One important message from the study is that metabolic health is something people can improve. While nobody can stop getting older, many metabolic risk factors respond to healthy lifestyle changes.
Maintaining a healthy weight, controlling blood pressure, improving cholesterol levels, staying physically active, eating a balanced diet, and managing diabetes may all help protect the brain’s blood supply.
The researchers believe future studies including more biological markers may uncover additional pathways connecting the body and the brain. For now, their findings suggest brain health should not be viewed separately from overall physical health.
Study analysis: This was a large, carefully designed study using two independent groups of participants and sophisticated brain imaging.
However, it was observational, meaning it identified associations rather than proving cause and effect. Even so, the results strengthen existing evidence that improving metabolic health may be an important strategy for protecting long-term brain function.
If you care about brain health, please read studies about low choline intake linked to higher dementia risk, and how eating nuts can affect your cognitive ability.
For more health information, please see recent studies that blueberry supplements may prevent cognitive decline, and results showing higher magnesium intake could help benefit brain health.
Source: PLOS Biology study authors.
