ASK THE DOCTOR

by Wesley W. Wilson, MD

NOTE: If you have any questions for "Ask the Doctor," please send them to the VOICE editorial office. The only questions Dr. Wilson will be able to answer are the ones used in this column.

Wesley Wilson, MD is an Internal Medicine practitioner at the Western Montana Clinic in Missoula, Montana. Dr. Wilson was diagnosed with type 1 diabetes in 1956, during his second year of medical school.

Q: A friend in my diabetes support group has "insulin resistance" big time and has to take 200-plus units of insulin a day. Is this much insulin hard on your body? Are there side effects?

A: Your friend has a frequently seen problem—though your friend's seems particularly severe. Type 2 diabetes represents 95% of all cases of diabetes, and insulin resistance is felt to be common, if not universal in type 2 diabetes. Current understanding suggests that persons who are likely to develop diabetes (type 2) first show elevated blood insulin levels—even though blood glucose levels are normal. It appears there is cellular resistance to insulin's effects, so larger amounts of insulin are required to perform the metabolic functions that insulin facilitates. The metabolic abnormality of increased insulin amounts with decreased insulin effect is termed "insulin resistance." During development of type 2 diabetes, the pancreas produces increased amounts of insulin for a time; but then, in many cases, the pancreas begins to fail. As insulin levels fall, often to levels which would be normal for persons without insulin resistance, the blood sugar becomes elevated. Unfortunately, the pancreatic failure is often progressive; sugar levels rise more as time goes on. It's of interest that in advanced type 2 diabetes (which requires insulin), the insulin doses needed to control the blood sugar are often higher than the amount of insulin produced by a normal person.

We all know that certain factors affect insulin resistance or sensitivity. Obesity, infections, and cortisone worsen insulin resistance. Exercise and weight loss increase insulin effectiveness. Sulfonylureas (such as Glucotrol) act to increase insulin production, whereas troglitazone (Rezulin) seems to increase insulin sensitivity. The American Diabetes Association strongly recommends that exercise and a diet to control obesity are key first steps toward control of type 2 diabetes. Physicians often see persons with newly-diagnosed type 2 diabetes, who are able to achieve normal blood sugars with diet, exercise, and weight loss, all steps known to reduce insulin resistance.

Your question: "Are the huge doses of insulin harmful?" is harder to answer. Experts argue about the toxicity of high insulin levels. It seems to me that the question should be: "Are the high insulin levels more harmful than the increased risk of complications that would follow if they were not used?" A number of studies have now shown that careful control of blood sugar, even with insulin or with drugs that increase insulin levels, can reduce the risk of complications, such as cardiovascular disease.

Several questions for your friend: Is she at an ideal weight? Does she follow a careful diabetic diet? Is she using Cortisone? Does she exercise regularly? Could she have a hidden infection? Careful control of blood sugar levels remains the essential aim in the effort to avoid the complications that are such a problem for persons who have diabetes.