Insulin, Intestinal Metabolism and Arteriosclerosis

Here is some research that provides further evidence of the links between systems of the body.

Diets high in sugar and fats can cause chronic elevations of insulin. High levels of insulin are a key feature of insulin resistance, a metabolic problem that affects at least a third of people living in the Western world and is also growing extremely rapidly in much of the developing world. Insulin resistance may be caused by a diet or genetics, or most commonly a combination of the two. It is known that insulin resistance can lead to the development of diabetes and arterial disease. The question has been how?

Almost forty years ago it was first suggested that insulin itself might be the problem. Not only is insulin involved in metabolism, it is also a potent growth factor for some of the smooth muscle cells found in the wall of major blood vessels. There has also been a suspicion that some of the metabolic effects of insulin increase the risk of arteriosclerosis by actions in the liver and intestines.

In research published in the journal Atherosclerosis, nutritional scientists at the University of Alberta have found a connection between high insulin levels and dysfunction of intestinal lipid metabolism. The finding provides critical support for the notion that impaired intestinal metabolic function plays a critical role in the development of cardiovascular disease.

Using a type of obese rat, the researchers found that excessive insulin slows the removal of chylomicrons from the blood stream following a fatty meal. Chylomicrons transport dietary fat from the intestine to the rest of the body.

Excessive amounts of insulin appear to alter the dynamics of the walls of blood vessels, allowing chylomicrons and cholesterol to build up in them. Over time this build up may creates blockages in the flow of blood.

It is good to see research that is re-examining the role of chylomicrons in vascular disease. Interest in them began to wane about twenty years ago, and since then most of the research and most of the screening recommendations have been based on cholesterol. Most doctors have been taught that cardiovascular disease is connected to increased levels of low-density lipoprotein (LDL) cholesterol, which is derived from the liver. However, fifty per cent of cardiovascular disease events occur in the presence of normal LDL-cholesterol levels. That is one of the reasons why many experts in metabolism have been saying for years that we must not forget the contribution of triglyceride and chylomicrons. This research confirms that we were right.

Although there are no accepted guidelines on this, people at risk of developing cardiovascular disease should not only have their LDL-cholesterol and HDL-cholesterol levels checked, but should also have the level of chylomicrons measured.

Technically it is not a difficult thing to do, although not all laboratories are able to do it. If chylomicron levels are high, it is an extra incentive to reduce fat consumption, and there are new medicine being tested that may help reduce chylomicron levels.

This research provides yet more evidence about the importance of the intestine in general health and disease. I constantly have people telling me that certain diets, colonic irrigation or probiotics may improve intestinal health and therefore general health and well-being. They may be correct. But what we really need is research to discover if there are viable ways of improving intestinal health that can prevent disease onset and progression.