Q: I have heard that diabetes is bad for the heart. Can you explain?

A: Your question is very timely, as February is National Heart Month. Everyone knows what diabetes is…it’s “sugar,” right? Well, yes and no. What does heart disease have to do with it? A lot, it turns out. Most borderline diabetic patients don’t think about it, let alone realize how serious being on that borderline can be. It’s not quite as bad as having “a touch of pregnancy,” but it’s close.

Diabetes is a huge risk factor for heart attack and it’s important to prevent or control it early as diabetics have the same risk as patients who are not diabetic, but have already had a heart attack. Diabetes is such large problem nationwide that new programs are being developed to help. One such program called the National Diabetes Prevention Program is now in Manitowoc. Just Google the program name plus Manitowoc and you can learn more about it.

There are two kinds of diabetes. Type I is caused by an inability to produce insulin as a result of damage to the pancreatic cells that produce it, and generally starts at an early age. Type II is more complicated. It is the result of becoming resistant to the insulin that the body makes. Both types cause high blood sugar levels and other abnormalities.

So what’s so bad about diabetes? Many things. Any food you eat gets broken down into basic parts, such as amino acids from protein, sugar from starchy foods like bread, grains, and potatoes (carbohydrates), and fatty acids from fat. For these nutrients to do any good, they have to enter cells. Sugar cannot enter cells without insulin. Fatty acids cannot enter cells without insulin and sugar. This explains why some of those low carb diets work. Without the carbohydrates to convert to sugar, all that fat gets flushed down the toilet because the fatty acids cannot enter the cells. Amino acids also get flushed when there is an excess.

What’s so bad about sugar, and indirectly, about diabetes? There is a relationship between sugar, fatty acids (transported as triglycerides), and their close relationship to insulin, and lipoproteins. We know the lipoproteins as “good” and “bad” cholesterol, but, in fact there are many more members of this group. They include “worse” and “deadly” cholesterol, as well as “cholesterol so good that it prevents hardening of the arteries.”

And then there’s insulin. If you are resistant to insulin and, as a result, make more of it, then it becomes bad for you. The bad effects of excess insulin include development of Type II diabetes, fatty liver, obesity, and arteriosclerosis, among others. Arteriosclerosis is the process by which blood vessels become hardened as a result of loss of normal vascular function and additional plaque deposition.

Elevated sugar, triglycerides, and insulin resistance also affect the lining of the blood vessels causing constriction, inflammation, and clotting abnormalities. This lining is called the endothelium. It is only one cell thick, and covers the inner surface of all blood vessels. It is the only thing keeping the blood separate from all the substances in the tissues that make the blood clot. The entire area of the endothelial layer is equivalent in size to the area of Lambeau Field. It is an enormous organ of enormous importance. Diabetes damages the endothelium. This is the process responsible for kidney failure, eye disease resulting in blindness, and neuropathy, which in turn causes inability to feel pain in the toes, which can result in their loss from gangrene. It also affects the circulation to the brain, resulting in strokes, and impairment of circulation to the sex organs, resulting in erectile dysfunction and impotence. This process affects all blood vessels, and therefore, the whole body.

Obstruction of a coronary artery is the more immediate cause of a heart attack and occurs in blood vessels where there has been mechanical disruption of the endothelium in blood vessels feeding the heart.

We now think of diabetes as an equivalent to coronary disease.

Dr. Vladimir Swerchowsky, F.A.C.C., is a cardiologist at Holy Family Memorial’s Heart and Vascular Center.

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