Do fat levels influence our memory?

High levels of LDL cholesterol, often called "bad cholesterol," are a well-known risk factor for heart disease. Given the connections between heart health and brain health, it seems logical that cholesterol may also influence memory and thinking skills.

While some studies support this idea, the evidence is mixed and raises questions about how cholesterol impacts cognitive performance. Understanding this relationship could reveal new ways to protect both heart and brain health, especially as we age.

Conflicting evidence across studies
Research on cholesterol and memory has given us inconsistent results. Some studies show that high levels of LDL cholesterol speed up memory decline, particularly in older adults. Other studies have found no such link.

In some populations, high levels of another cholesterol type, HDL cholesterol, known as "good cholesterol," seem to support better memory.

The differences may be due to variations in how cholesterol is measured, the timing of assessments, or the unique lifestyles and health conditions of the groups studied.

The study
A recent long-term study investigated a large, diverse group of adults in the United States. The study had 13,258 participants. At baseline, 56% of the participants were 65 years or older.

Over 14 years, the researchers tracked changes in their cholesterol levels and memory performance.

They found a small but notable connection between higher levels of good cholesterol and better memory scores as people aged. However, bad cholesterol showed inconsistent effects on memory, with some evidence of harm in women and younger adults but little impact in others.

These results align with previous research suggesting that maintaining good cholesterol levels might support cognitive health, but the effects are modest compared to factors like education or genetic risks.

Challenges and future directions
The findings suggest that cholesterol’s role in brain health is complex and influenced by multiple pathways.

High levels of the "good" cholesterol HDL have a positive impact on brain function as we age - but too much of the "bad" LDL cholesterol has not yet been found to impact brain health.

For now, strategies focusing on other proven factors, such as education, strong social networks, and managing genetic risks, may offer more reliable ways to preserve memory and reduce dementia risk by promoting neural resilience.

Nevertheless, maintaining healthy cholesterol levels remains an essential part of overall good health.

About the scientific paper:

First author: Silvia Miramontes, USA
Published: Alzheimer’s & Dementia: Translational Research & Clinical Interventions, January 2025
Link to paper: https://alz-journals.onlinelibrary.wiley.com/doi/10.1002/trc2.70021