Poor metabolic health ages the brain

The study showed that the brain is affected by two separate and independent axes (the aging axis and the metabolic health axis). This means that even a relatively young person can exhibit changes in the brain that are typical of a poor metabolic status.

The effects of these axes are different:

• The aging axis gradually destroys the structural integrity of the brain and leads to cortical thinning and vascular dysfunction, which slows down blood flow in the brain vessels.
• The metabolic health axis works differently. There is no single main factor; instead, a whole range of indicators (weight, blood pressure, cholesterol, etc.) simultaneously affect the brain. Their overall effect is a reduction in cerebral perfusion, i.e., a decrease in the volume of blood reaching the brain tissue.

Because of this, people with poorer metabolic indicators are more likely to have difficulties with cognitive flexibility—the ability to switch between different tasks and competing demands. This association was particularly pronounced in women.

Scientists sought to find simple and accessible clinical indicators that could reliably reflect the state of the brain. To do this, they compared conventional medical data (BMI, blood pressure, lipids, and glucose levels) with detailed MRI parameters (structure, connectivity, and blood flow).

The data was collected from two large cohorts:

• 597 participants in the Human Connectome Project–Ageing (ages 36–100) to identify underlying biological patterns;
• 3,013 participants of the UK Biobank (age 51–83) — to check whether these patterns are preserved in another group.

To search for relationships between indicators of the body and the brain, the method of partial least squares (PLS) was used. It allowed to identify the main patterns and show that age and metabolic factors do indeed act through different paths.

It turned out that metabolic health acts as a modifiable risk factor. Unlike aging, which cannot be affected, a person can adjust weight, cholesterol levels, and blood pressure. This provides a real chance to protect the blood supply to the brain and thereby maintain its health.

Nowadays, routine clinical indicators are rarely associated with the state of the brain, and detailed MRI data is almost not used in routine practice. The work shows how important it is to consider the body and brain as a single system and metabolic problems — not only a risk to the heart or the development of diabetes, but also a direct threat to cerebral blood flow and cognitive abilities.

The authors emphasize that metabolic health should be given a more prominent place in public recommendations for maintaining brain health. In future studies, it is planned to expand the set of biomarkers to uncover the connections between the body and the brain not only in the context of metabolism, but also beyond it.