A recent study has found that high levels of so-called “good cholesterol,” known as HDL-C, may be linked to an increased risk of Alzheimer’s disease in women after menopause, challenging long-held assumptions about its protective role.

The research, published in the Journal of Clinical Endocrinology & Metabolism, suggests that after menopause, the quality of HDL cholesterol may matter more for brain health than the overall amount present in the blood.

The study was led by scientists from the University of Pittsburgh School of Public Health, who found that as women age, the function of HDL particles can decline, potentially affecting cognitive health.

HDL cholesterol particles vary in size and function, and not all types offer the same benefits. Researchers analysed blood samples from 503 women participating in a long-term health study. Over time, they observed an increase in larger HDL particles, but these were less effective than smaller HDL particles.

Between 2000 and 2016, participants underwent regular memory and cognitive tests. The findings showed that women with higher levels of small HDL particles, particularly those rich in phospholipids, performed better on memory tests as they aged. Phospholipids are essential fats that help maintain healthy brain cells.

Dr. Samar El Khoudary, the study’s lead author and a professor at the University of Pittsburgh, said the results are significant because memory decline is often an early sign of Alzheimer’s disease.

However, the researchers also noted that earlier studies by the same team showed healthy lifestyle habits can improve how well HDL particles function. Regular physical activity, maintaining a healthy weight, eating a balanced diet, and avoiding smoking were all linked to better HDL quality.

The findings suggest that even in women with high HDL levels, adopting a healthy lifestyle may enhance the protective function of cholesterol particles, potentially helping to safeguard brain health as well as heart health.