Insulin and Type 2 Diabetes: What You Should Know

The decision to start taking insulin isn't easy. How do you know if you need insulin? And if you do, what's the best way to start? Before you and your health care provider make a decision, learn the latest on insulin.


Insulin and Type 2 Diabetes

If your health care provider offered you a medication to help you feel better and get your blood sugar under control, would you try it? If so, you might be ready to start taking insulin.

Does insulin immediately make you think of type 1 diabetes? Think again. Between 30 and 40 percent of people with type 2 diabetes take insulin. In fact, there are more people with type 2 diabetes who take insulin than type 1 because of the much larger number of people with type 2. Experts believe even more people with type 2 should be taking insulin to control blood sugar -- and the earlier, the better. With an increase in people developing type 2 at a younger age and living longer, more and more people with type 2 will likely be taking insulin. 

"If you live long enough with type 2 diabetes, odds are good you'll eventually need insulin," says William Polonsky, Ph.D., CDE, associate clinical professor of psychiatry at the University of California, San Diego; founder and president of the Behavioral Diabetes Institute; and author of Diabetes Burnout: What to Do When You Can't Take It Anymore (American Diabetes Association, 1999).

Producing Less Insulin Naturally Over Time

Research has shown that type 2 diabetes progresses as the ability of the body’s pancreatic beta cells to produce insulin dwindles over time. Your beta cells -- the cells in the pancreas that produce insulin -- slowly lose function. Experts believe that by the time you're diagnosed with type 2 diabetes, you've already lost 50-80 percent of your beta cell function and perhaps the number of beta cells you had. And the loss continues over the years.

"About six years after being diagnosed, most people have about a quarter of their beta cell function left," says Anthony McCall, M.D., Ph.D., endocrinologist and James M. Moss Professor in Diabetes at the University of Virginia School of Medicine. "With this minimal function, the need for injected insulin increases."

Some experts say initiating insulin or other blood glucose-lowering medications early in the course of type 2 diabetes can lower blood glucose and even preserve some beta cell function.

Insulin resistance is another consistent factor in type 2 diabetes. This refers to the body's inability to effectively use the insulin you make. So type 2 diabetes becomes a twofold problem even at diagnosis: not enough insulin is being made, and too little of the insulin that is made can effectively lower blood sugar. To treat insulin resistance, most guidelines recommend starting with a drug called metformin at diagnosis. Metformin is commonly used because is treats the insulin resistance, and it's safe, reliable, effective, and available generically so it’s relatively inexpensive.

Making the Most Out of Your Own Insulin

To stay healthy with type 2 diabetes over the years, the key is controlling your blood sugar, blood pressure, and blood lipids (cholesterol). These are the so-called ABCs of diabetes care -- A is for A1C (average blood glucose), B for blood pressure, and C for cholesterol (blood lipids). To control blood sugar, you need to continually and progressively be adjusting your diabetes care to compensate for your body's waning supply of insulin and growing level of insulin resistance.

At diagnosis, some people still produce enough insulin to hit their blood sugar targets by eating healthfully, getting physical activity, and losing weight. In fact, losing 10-20 pounds can make a dramatic impact early on. But research shows that most people need to start diabetes medications and/or insulin right away.

As the body gradually produces less insulin, nearly everyone with type 2 diabetes needs one or more oral or injectable blood glucose-lowering medications, which might include insulin. Additionally, there is now a category of blood glucose-lowering medicines called incretin mimetics or GLP-1 analogs that are injectable: Byetta, Victoza, and Bydureon are the three approved brands.

When you start insulin or any blood glucose-lowering medication, you still need to eat healthfully and be physically active.

Where Manufactured "Human" Insulin Comes In

The goal of taking insulin injections is to mimic your body's normal insulin response. People who take insulin most likely will eventually need a combination of rapid- or short-acting and long-acting insulins to mimic normal insulin function and to control blood glucose.

A normal pancreas releases insulin constantly, not just when you eat, says John Walsh, P.A., CDE, coauthor of Using Insulin: Everything You Need for Success with Insulin (Torrey Pines Press, 2003). Adults produce about 1 unit of insulin per hour. This is called basal insulin or background insulin.

In response to food, insulin is released from the pancreas in two phases:

1. The first burst occurs within 15 minutes of your first bite in response to rising blood glucose.

2. The second phase happens more slowly, over the next one-and-a-half to three hours, to match the rise in blood glucose from the food you ate, which is called bolus insulin or mealtime insulin.