High levels of good cholesterol have been linked to an increased risk of Alzheimer's disease. New research adds an interesting twist. Scientists now suggest that when it comes to dementia risk, the quality of HDL, or high-density lipoprotein, is more important than the quantity.

According to the study conducted by researchers at the University of Pittsburgh, the number of larger HDL particles in women's bodies increases during menopause, and these larger particles are less effective in supporting cognitive health than their smaller counterparts.

In the study published in the Journal of Clinical Endocrinology & Metabolism, researchers examined the unique connection between good cholesterol and cognitive health using blood samples from 503 women involved in the Study of Women's Health Across the Nation (SWAN).

To understand how the quality of HDL cholesterol might influence the risk of dementia, the researchers tracked the changes in the women's HDL particles as they aged along with their cognitive function over 16 years from 2000.

Researchers found that having more total HDL particles with smaller HDL particle sizes during midlife was linked to better memory and processing speed. They also observed that participants who showed increases in specific types of HDL, such as HDL-PL, apoA-1, medium HDL-P, and total HDL-P, while experiencing less increase in particle size as they aged, had better cognitive health.

"We were able to show that as early as midlife, women who have more of the smaller-sized particles and those whose particles' concentrations of phospholipids increased over the menopause transition are more likely to experience better episodic memory later in life," said Samar R. El Khoudary in a news release.

The research team had previously discovered that adopting Life's Essential 8, the key measures for improving and maintaining cardiovascular health as recommended by the American Heart Association (AHA) could enhance the quality of HDL particles in the bloodstream.

"That's the good news in this developing picture of brain health and the 'not-so-good-after-all' cholesterol. Even though higher levels of HDL-C may not be protective as you get older, there are things you can do that might help, even as early as your 40s. The same modifiable risk factors that the AHA is advocating for—including physical activity, ideal body weight and quitting smoking—can help you protect your brain, too," said El Khoudary.

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