Editor’s Note: This is the third post in our miniseries about diabetes drugs. Tune in on August 28 for the next installment.
The first installment of our medicines miniseries, “Diabetes Drugs: Insulin,” yielded a variety of questions from readers. Here, we present a selection of these questions along with responses from Dr. Marino.
My endocrinologist assures me that I have Type 2 diabetes because I have predominantly abdominal fat. Do you have any thoughts on this?
The diagnosis of adult-onset diabetes is not always straightforward. There is a condition called latent autoimmune diabetes of adults, or LADA, that may occur in up to 10% of people with diabetes who initially do not require insulin. You should discuss this with your health-care provider; if appropriate, he could check for this condition with various blood tests. A diagnosis of LADA might have implications for your therapy, since there is some evidence that people with this condition have more of an insulin deficiency than people with Type 2 diabetes. However, no large studies have been done to help determine the best therapy for LADA.
With that said, the goal is to optimize the current insulin therapy you are on. As mentioned in “Diabetes Drugs: Insulin,” the best method of insulin administration is to combine long-acting and rapid-acting insulin to provide good blood glucose control throughout the day without causing hypoglycemia (low blood glucose). I would suggest that you work closely with your health-care provider to optimize your blood glucose control. This may mean more frequent blood glucose measurements throughout the day to determine how to change your daily doses. Another option you may want to explore with your health-care provider is an insulin pump. And as always, a diet and exercise plan that is designed in partnership with your health-care provider is recommended.
The goal of any therapy for diabetes is to keep blood glucose levels within the target range. In multiple large clinical trials such as the Diabetes Complications and Control Trial (DCCT) and Epidemiology of Diabetes Interventions and Complications (EDIC) Study, which looked at people with Type 1 diabetes, and the United Kingdom Prospective Diabetes Study (UKPDS), which looked at people with Type 2 diabetes, complications were significantly reduced by improved blood glucose control. The beneficial effects in the UKPDS study occurred regardless of the drug used to obtain good control (including insulin).
Within two weeks of starting insulin therapy, I gained 9 pounds, mostly in the waist area. I exercise regularly, but the weight problem remains. Doesn’t this defeat the purpose of using insulin?
As noted in “Diabetes Drugs: Insulin,” insulin is an energy-storing hormone that can be associated with weight gain. There are many potential reasons for insulin causing weight gain, but one possible reason is that the insulin produces a lower blood glucose level than your body is used to, which leads to “defensive” eating to combat the perceived hypoglycemia. You should keep track of your diet and your blood glucose levels during the day in a diary that you can review with your health-care provider.
There are several drugs for Type 2 diabetes, including metformin (brand name Glucophage and others) and exenatide (Byetta), that do not produce weight gain or that produce weight loss. However, none of them are as effective at improving HbA1c (an indicator of blood glucose control over the previous 2–3 months) as insulin. You should discuss with your doctor what other options might be of use in your specific circumstances.
Is it possible to be allergic to insulin?
Insulin allergy does occur, but it is relatively rare. Medically speaking, an allergy to insulin usually involves the development of a very specific class of antibodies called IgE antibodies. (This is the same class of antibodies that causes allergies to other drugs, such as penicillin.) IgE antibodies are not to be confused with insulin antibodies, which do occur in many people who receive insulin. These insulin antibodies are of the IgG class and do not cause an “allergic” reaction. To read about a person with a true insulin allergy, click here.
I’d love to understand how exercise makes insulin more effective. I have Type 1 diabetes, and when I exercise, I need less insulin — sometimes even no insulin — even if I consume carbohydrate while doing this.
Insulin requirements vis-à-vis exercise is a very large topic. A person’s blood glucose response to exercise depends on how well the person’s blood glucose is in control and the type and intensity of the exercise, as well as the person’s level of physical fitness. In general, glucose uptake in muscle depends on glucose transporters (proteins that serve to ferry glucose into the cell) in the muscle cell membrane, and these are known to increase during exercise and to stay elevated for several hours after exercise. Many other aspects of how these transporters and other signals are stimulated by exercise are not fully known. For more details, see the book Nutritional Applications in Exercise and Sport, by Ira Wolinsky and Judy A. Driskell, as well as the article “Exercise-induced increase in muscle insulin sensitivity.”
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