There are two types of cholesterol, one that can make the arteries less flexible and therefore make a person more susceptible to heart attack or stroke; and the other that actually protects against heart attack. Cholesterol cannot dissolve in the blood, which means it has to be transported to and from the cells by carriers known as lipoproteins. Low-density lipoproteins, or LDL, are considered "bad" cholesterol. When too much bad cholesterol is circulating in the blood, LDL can slowly build up on the inner walls of the arteries, possibly even teaming with other substances to form plaque, a thick, hard deposit that narrows the arteries and makes them less flexible.

High-density lipoprotein, or HDL, is what's considered "good" cholesterol. That's because medical experts feel HDL carries cholesterol away from the arteries and back to the liver, where cholesterol is then passed from the body. In addition, some experts also feel HDL removes excess cholesterol from arterial plaque, slowing its buildup as a result. And though cholesterol is commonly, and falsely, considered a dirty word, low levels of HDL actually increase a person's risk of heart disease. A simple blood test can help men and women learn their HDL and LDL levels.

A study reveals that high levels of bad cholesterol are associated with mild cognitive impairment (MCI), which covers language disorders, memory loss, and can even influence the mood, in people more than 50 years old that may precede Alzheimer’s and dementia.

This was demonstrated by a study conducted at Medical University of South Carolina and other schools.

Journal of the American Medical Association