Good Cholesterol May Lower Risk of Alzheimer’s Disease
Heart-Healthy HDL Cholesterol May Also Protect Brain From Dementia
A Complex Role for Cholesterol in the Brain
Reitz says that while she found an association between HDL and this form of dementia, she’s not really sure why it may be protective.
“There’s a lot of research trying to find out why HDL is associated with Alzheimer’s disease and what the biological mechanism is behind that. There are different potential explanations, which we’re trying to find out,” Reitz says. “One is that HDL affects the risk of stroke and stroke is associated with Alzheimer’s disease.”
“HDL is one of the major carriers of protein in the brain,” says Lenore Launer, PhD, chief of the Neuroepidemiology Section in the Intramural Research Program at National Institute on Aging. “HDL can go out of the brain, it can go into the brain, so there is some flux between in and out of the brain, which makes it difficult to say how much of the periphery measurements reflect what’s going on in the brain.”
In 2001, Launer published a study in the journal Neurology that came to the opposite conclusion of the Columbia study. She found that Japanese-American men with higher HDL cholesterol levels were more likely to have Alzheimer’s-related plaques and tangles in their brains.
“I’d like to see some consistency across the literature. And the HDL finding has not been consistent across the literature,” Launer says. “Until the message is pretty consistent across studies, I really wouldn’t have any recommendations about levels of HDL and Alzheimer’s disease.”
Keeping the Heart Healthy May Also Help the Brain
While it may not make sense to boost HDL levels to try to prevent Alzheimer’s disease just yet, Launer and other experts note that higher levels of HDL have clearly been shown to protect the heart, so for that reason alone, they think it’s smart to keep good cholesterol in mind at every checkup.
“I tell everybody, let’s face it, you can lower your risk of heart disease,” says Peter Davies, PhD, director of the Litwin Zucker Research Center for the Study of Alzheimer’s Disease at the Feinstein Institute for Medical Research in Manhasset, N.Y. “If you get your cholesterol under control, with lifestyle modifications and maybe medication, you can reduce your risk of heart disease and I think probably, if you do that, you’ll reduce your risk of Alzheimer’s, too.”
Guidelines recommend that men raise HDL levels that are under 40 mg/dL and that women increase HDL numbers under 50 mg/dL. An HDL of 60 mg/dL or higher is optimal.