Memory Loss and Your Cholesterol

Your cholesterol levels may be associated with your memory. Studies suggest that memory loss is associated with low levels of high-density lipoprotein (HDL) the "good cholesterol" and high levels of triglycerides and low-density lipoprotein (LDL), the "bad cholesterol." Researchers believe this memory loss may lead to dementia later in life.

Studies Find Low HDL or High LDL Raises Memory Loss Risk

Research shows that there may be a link between cholesterol levels and memory loss. But the impact of lowering cholesterol levels is not consistent.

• A study, published in July 2008 in Arteriosclerosis, Thrombosis and Vascular Biology: Journal of the American Heart Association, found that, by the age of 60, men and women with low levels of HDL were 53 percent more likely to have memory loss than those with higher levels. The use of statin drugs to raise HDL levels or to lower levels of LDL was not found to have any association with memory loss in the study.
• And this isn't the first time researchers have found a link between cholesterol and memory problems. An earlier study in 2002, published in the Archives of Neurology, found that women with high levels of LDL had increased degrees of cognitive impairment, including memory loss. Four years later, study subjects who lowered their LDL levels also lowered their chances of suffering from cognitive impairment.
• In 2004, a study from the Netherlands found that a diet high in cholesterol and saturated fat was linked to an increased risk of cognitive decline among middle-aged study subjects. That study, published in the journal Neurology, also concluded that consumption of fish and fish oil was associated with a lower risk of cognitive decline; the reputation of fish as "brain food" appears to be intact.

Solving the Mystery of Cholesterol and Memory Loss

How does cholesterol affect memory and cognitive function? The precise answer to that question remains a mystery. Researchers speculate that HDL may improve memory in a number of ways. HDL has anti-inflammatory and antioxidant properties, which may improve brain function. HDL may also prevent the formation of beta-amyloid that forms in the brain tissue of Alzheimer's patients.

A review of studies in 2011 noted that "cholesterol seems to be intimately linked with the generation of amyloid, " which develops in Alzheimer's disease. The majority of the studies they looked at found an association between cholesterol and Alzheimer's disease.

William Connor, M.D., professor of medicine at Oregon Health and Science University in Portland, Oregon, says that cholesterol affects brain functioning primarily through the link between LDL and strokes, which are caused by atherosclerotic plaque formation in the blood vessels of the brain.

"High cholesterol levels in the blood can predispose the deposition of plaque in the blood vessels," says Connor, a specialist in atherosclerosis (the process by which deposits build up in arteries). And, he adds, "stroke can result in memory loss."

And a more recent study, published in 2021 found that participants with high triglyceride levels and low HDL levels showed decreased integrity of the hippocampus, which is an area of the brain that is involved in memory—and this area often shows signs of amyloid buildup and atrophy (shrinking) in people who have dementia.

What You Can Do About Cholesterol and Your Memory

While researchers continue to piece together the puzzle of cholesterol and memory loss, there's a lot of action you can take now if you're concerned about your cholesterol levels.

According to the American Heart Association, getting regular exercise and avoiding tobacco smoke can help to moderate cholesterol levels. Cholesterol-lowering drugs can also help you achieve your cholesterol goals.

And eating a heart-healthy diet is strongly recommended. In addition to avoiding saturated fats and cholesterol, Dr. Connor and other experts encourage people to get plenty of fiber, eat fruits and vegetables regularly (aim for at least five to seven servings a day), and have one or two servings of fish per week.