High Insulin Levels May Lead to Heart Disease

Researchers at the University of Alberta report that there is a defined link between high insulin levels and defective lipid metabolism, helping to explain the correlation between diabetes and heart disease. This also helps to understand how unhealthy eating habits can eventually result in heart disease.

In a paper submitted to the journal Atherosclerosis, Donna Vine, one of the researchers, studied blood vessels of insulin-resistant rats for build up of chylomicron cholesterol particles following ingestion of a high fat-containing meal. Chylomicrons are large lipoprotein particles that transport lipids to the liver, where they are broken down. They are of the same category of molecules as HDL (high density lipoprotein), which carries cholesterol instead of lipids to the liver for processing. Because the rats are insulin-resistant, more insulin is required to clear sugars and fats from their bloodstream compared with normal rats. Vine and her colleagues found that higher insulin levels reduced the rate of chylomicron removal from the blood stream following a meal. Due to their slower clearing rate, the chylomicron particles would be more likely to stick to blood vessels, leading to arterial plaque build up and heart disease.

"Now that we know high levels of insulin are associated with altered intestinal chylomicron metabolism and a build up of these particles in the blood vessel walls, our next step is to use this animal model to look closer at the cellular mechanisms and try to figure out how this happens," stated Vine. She and her colleagues believe that, while LDL (low-density lipoprotein) also has a tendency to stick to arterial blood vessel walls, resulting in heart problems, a more accurate indicator of future heart disease is chylomicron cholesterol. This is shown the fact that, in about 50% of cardiovascular disease events, LDL levels are found to be normal.