Cholesterol and Lipoproteins
Cholesterol is not all bad — it’s a necessary part of our body chemistry. We get it from two sources; our body produces it in our liver, which accounts for about seventy-five percent of what we have, and the other twenty-five percent comes from what we eat. It’s only found in the animal foods we consume.
All cholesterol is combined with proteins and phosphate to make lipoproteins. Lipoproteins are the carriers for fat and cholesterol in our bloodstream. Since blood is a water-based medium, it’s necessary to have a substance that can transport fat and cholesterol (which has solubility characteristics similar to fat) in the bloodstream. There are four types of lipoproteins:
Chylomicrons — These transport dietary cholesterol to the liver for processing and are the dominant type of lipoprotein following a fatty meal.
VLDL (Very Low Density Lipoprotein) — After the fat has been removed by the liver, this is the remnant of the chylomicron.
LDL (Low-Density Lipoprotein) — This is formed in the liver and is the primary carrier of cholesterol to the cells of the body. It’s the primary source of buildup of fatty deposits and cholesterol in the arteries, especially the coronary arteries. This is the BAD cholesterol and the more that’s in your blood, the greater your chance of coronary heart disease.
HDL (High-Density Lipoprotein) — This is the GOOD cholesterol. It carries cholesterol from parts of the body to the liver, where it’s removed from the body. HDL helps the body get rid of cholesterol, thereby reducing the buildup in arteries. The higher one’s HDL, the better.
Triglycerides — Another form of fat in our body is a triglyceride. It consists of three fatty acid molecules attached to a sugar alcohol called glycerol. Well over ninety percent of the fat in our body is in the form of triglycerides, including all that’s stored in our fat cells. Lipoproteins transport most fat in the form of triglycerides. A high triglyceride number is linked to coronary artery disease in some people.