A study conducted on 3,673 civil servants revealed that the participants with low levels of High Density Lipoprotein (HDL) were likely to suffer a memory loss by the age of 60.

The study was started in 1985 in London, where the Doctors took blood samples of the participants on two occasions, five years apart, and their short term memory was assessed. The participants were supposed to recall a list of 20 words  given to them by the doctors. The participants with low HDL level showed 27 percent increased risk of loss of memory at age 55. They were again tested at the age of 60 and this time the memory loss risk increased upto 63 percent.

Archana Singh, a senior fellow researcher at University College of London and the French National Institute for Health and Medical Research, said, "The low HDL cholestrol level of 40 milligrams per deciliter of blood, might be a risk factor for demntia."

Good cholestrol or HDL might prove beneficial for Alzheimer's patients as well, because it helps control the formation of beta analoids, a major component found in the Alzheimer's patients, besides other benefits of reducing the risk of heart attacks and strokes.

The HDL levels can be increased by aerobic exercises, weight loss, not smoking, cutting out trans fatty acids, eating more monounsaturated fats and increasing the intake of soluble fibers such as, whole grains, fruits and vegetables.