Oct. 1 (UPI) — Drugs prescribed for Type 2 diabetes may actually increase insulin resistance in the body by boosting production of the hormone to unhealthy levels, causing the disease to worsen, researchers from Boston University said Friday.
The medical field has long believed that insulin resistance, or increased insulin tolerance, causes elevated levels of the hormone in the blood, they said.
As a result, prescription medications such as metformin and a class of drugs called thiazolidinediones, or TZDs, are often used to lower blood sugar in people with Type 2 diabetes by increasing the release of insulin into the bloodstream.
However, elevated blood insulin levels in people with the disease may actually result from over-production of the hormone by beta cells in the pancreas, they argued in a paper published Friday by the journal Diabetes.
This process, called hyperinsulinemia, may be caused by excess nutrients and environmental toxins, and medications designed to boost insulin production may lead to the build up of more tolerance against it after long-term use, the researchers said.
“Our article describes a testable model in which chronic excess nutrient exposure results in insulin hypersecretion from the beta cell contributing to hyperinsulinemia,” co-author Barbara E. Corkey said in a press release.
“Hyperinsulinemia normally precedes measurable insulin resistance and Type 2 diabetes. It is viewed by many as a normal response to insulin resistance rather than its potential cause,” said Corkey, a professor emeritus at Boston University School of Medicine.
Insulin is a hormone produced by the pancreas that allows tissues such as muscle and fat to process sugar, or glucose, from the blood for use as fuel for the body’s energy needs, according to Corkey and her colleagues.
It is released from the pancreas into the blood stream when blood sugar levels increase, perhaps after a meal, to keep them in the normal, healthy range.
People with insulin resistance, or impaired insulin sensitivity, have built up a tolerance to the hormone, according to the American Diabetes Association.
Resistance makes insulin less effective and, as a result, more is needed for the body’s fat and muscle cells to process sugar and for the liver to continue to store it, the association says.
This means more sugar accumulates in the blood, to unhealthy levels in people with Type 2 diabetes, causing the pancreas to produce even more insulin, it says.
Because of this increased production of insulin, which may lead to hyperinsulinemia, many people with Type 2 diabetes have elevated insulin even when their blood sugar is normal, Corkey and her colleagues said.
Medications that further increase insulin production only compound the problem by essentially telling the body it needs more and more of the hormone to process sugar, they said.
“Increased insulin release from the pancreas drives blood insulin levels higher causing and contributing to insulin resistance,” Corkey said.
“New therapeutic solutions that include lowering insulin levels before Type 2 diabetes develops may be warranted to prevent insulin resistance further developing into Type 2 diabetes,” she said.