Memory Loss Linked to Cholesterol?

Author: Neomi Heroux

Cholesterol has long been cited as bad for our health, known to increase risk for heart disease. New evidence suggests that one of the components of cholesterol HDL (the good cholesterol) may also play a role in how well older individuals retain their mental acuity.

A study of 3,673 civil servants found that participants with low levels of HDL were likely to suffer a decline in memory by the age of 60. The long-term investigation began in London in 1985. Blood samples were taken from the participants on two occasions, five years apart, and their short term verbal memory was assessed. Doctors recited a list of 20 words and the subjects were asked to write down as many as they remembered. The test was conducted at age 55 and again at age 60. Those with low HDL levels performed 27 percent worse at age 55, and at age 60 the gap was 63 percent worse compared to individuals with high levels of HDL.

The definition of low HDL was less than 40 milligrams per deciliter of blood, and high HDL was 60 mg or more. According to Archana Singh-Manoux, the lead author and a senior research fellow at University College London, and the French National Institute for Health and Medical Research, "A low level of HDL may be a risk factor for memory loss in late midlife, low HDL cholesterol might also be a risk factor for dementia."

Studies have shown that high levels of HDL protect against heart disease, and drug makers have been working on medical ways to raise HDL. Most cholesterol medications (statins) such as Pfizer Inc's Lipitor and AstraZenaca's Crestor significantly lower LDL, but raise HDL only a small amount. Niacin, a B vitamin, is the most effect method of raising HDL, but causes extreme flushing in some individuals and limits its use. An extended release version from Abbot Laboratories is designed to reduce this side effect.

It is not clear how HDL and memory loss are related. HDL helps to remove excess cholesterol from the blood, and may control the formation of amyloid plaque that develops in the brains of Alzheimer's patients. Since the HDL-memory function link is not clear at this time some experts caution it is too soon to try medical means to raise HDL. The lower HDL might be a sign of increased risk of memory loss not the cause of the problem. If that is the case improved HDL levels won't help the patient. The studies do show that more research needs to be done on the connection between HDL and brain function.

How can HDL be raised? The proven methods include aerobic exercise, weight loss (your waist to hip ratio is particularly important), stop smoking, cut out trans fatty acids, eat more monounsaturated fats, increase your soluble fiber (whole grains, fruits and vegetables). And if you are lucky your doctor will tell you to have a glass of red wine with dinner.