Fatty diets that involve large amounts of meat and dairy products encourage diabetes by disrupting the work of a single gene responsible for insulin production, scientists have found.
Researchers at the University of California San Diego School of Medicine have pinpointed a molecular link between the high-fat diet common in the West and type 2 diabetes. They hope it will offer new ways to treat the condition.
Type 2 diabetes is often associated with insulin resistance, when the body ceases to react properly to insulin. It can greatly increase the risk of a range of serious and potentially life-threatening conditions, including heart disease, stroke, nerve damage and damage to organs and eyes.
The new study shows that a single gene responsible for encoding an enzyme known as GnT-4a is a key to enabling beta cells in the pancreas to detect blood glucose levels and trigger the production of insulin when needed. The researchers demonstrated in tests on mice that this enzyme is suppressed by a high-fat diet. Without enough GnT-4a enzyme, pancreatic cell failure occurs, resulting in type 2 diabetes.
Western-style diets consist mainly of processed foods, red meat, dairy products, refined carbohydrates, food additives, junk foods, fast foods and snacks with a high salt, sugar and saturated fat content.
By contrast, the Asian diet is relatively low in meat and dairy foods.
More than 200 million people worldwide have been diagnosed with type 2 diabetes, almost 20 million of them Americans, mainly as a consequence of the growing obesity problem.
While it is widely recognized that type 2 diabetes is directly related to a high-fat diet and excess weight, until now researchers had not known why.
Jamey Marth, UCSD professor of cellular and molecular medicine and a researcher with the Howard Hughes Medical Institute, said the discovery could have a significant effect on future research.
"We have discovered a mechanistic explanation for beta cell failure in response to a high-fat diet and obesity, a molecular trigger which begins the chain of events leading from hyperglycemia (elevated blood glucose levels) to insulin resistance and type 2 diabetes," Professor Marth said.
"This finding suggests new approaches to the prevention and treatment of diabetes."
Published in the journal Cell Dec 2005