An Overview of Hyperinsulinemia

Hyperinsulinemia is characterized by abnormally high insulin levels in the blood and is a condition associated with type 2 diabetes, but alone it is not technically a form of diabetes. Hyperinsulinemia is also a factor in insulin resistance, obesity, and metabolic syndrome.

Insulin is a hormone produced by the pancreas that has many functions. One of insulin's main functions is to transport glucose (sugar) from the bloodstream into the cells where it can be used for energy. In some people, insulin does not work properly because cell receptors have developed a resistance to insulin, which means that insulin is ineffective at removing glucose from the bloodstream. This condition is called insulin resistance.

Consequently, glucose builds up in the bloodstream. Because the body is unable to access the glucose for fuel, the cells become starved and you may feel excessively hungry or thirsty. The body attempts to lower blood sugar levels by releasing even more insulin into the bloodstream. As a result, the body ends up with both high blood sugar levels and high insulin levels. 

An excess of insulin can result in low blood sugar being circulated throughout the body, hypoglycemia (or the condition of having low blood sugar) may be an indicator to its presence. This is particularly noted in infants born to mothers who have uncontrolled diabetes. Other symptoms of hyperinsulinemia include high blood sugar from insulin resistance, high blood cholesterol, and triglyceride levels, elevated blood pressure, fatigue, weight gain, difficulty losing weight, and increased carbohydrate cravings/sugar.

In pregnant women with uncontrolled blood sugar levels, the fetus is exposed to high levels of sugar. In response, the fetal pancreas undergoes changes to produce more insulin. After birth, the baby will continue to experience excess levels of insulin or hyperinsulinemia and will experience a sudden drop in blood sugar levels. The baby is treated with glucose after delivery and insulin levels usually return to normal within two days.

Hyperinsulinemia is primarily caused by insulin resistance. When blood sugar increases, the pancreas' beta cells respond by producing and releasing more insulin into the bloodstream to try to keep blood glucose at a normal level. As cells become insulin resistant, however, the level of insulin keeps rising up.

It may also occur as a side effect of gastric bypass surgery, perhaps because beta cells were previously supporting larger body mass and then haven't adjusted post-procedure.

In rare cases, hyperinsulinemia may be caused by a tumor of the beta cells of the pancreas (insulinoma) or by excessive growth of the beta cells, a condition called nesidioblastosis.

Hyperinsulinemia may be diagnosed by testing your blood insulin and glucose levels. It may also be diagnosed by routine blood tests when undergoing testing for diabetes or other conditions, such as high cholesterol.

Medication and lifestyle changes to ameliorate hyperinsulinemia are similar to those for type 2 diabetes. Healthy eating, especially a diet that is lower in carbohydrates, and regular exercise, including high-intensity interval training (HIIT) are especially helpful in improving insulin sensitivity.

Some diabetes medications increase insulin levels while lowering blood sugar levels. One drug that successfully lowers both blood sugar and insulin levels, enhancing insulin's action, is metformin. Metformin is a first-line agent for treating type 2 diabetes—this is the only drug that is approved by the FDA for diabetes prevention and is also used in patients with metabolic syndrome or prediabetes.

With the help of your care provider, hyperinsulinemia can be well-managed and controlled thanks to both medication and lifestyle changes such as eating a balanced diet and aerobic exercise. However, there has been an increase in recent research on the role of hyperinsulinemia in the development of type 2 diabetes and obesity, which could develop if the condition is left unchecked. Be sure to keep up with yearly blood tests through your physician and keep an eye on any potential symptoms.