Diets high in fat can disrupt blood sugar
levels and trigger diabetes, researchers said in a study
that helps explain the link between obesity and a disease
typically linked to sugar.
Fatty foods can suppress an enzyme crucial to the production
of insulin, which regulates sugar in the blood, according
to scientists at the University of California at San Diego.
Obesity has long been linked to type 2 diabetes, the
most common form of the disease in which the body does
not make enough insulin, or cannot properly use it.
In the United States, two out of three adults are overweight
or obese. Experts have said obese people are up to 80
times more likely to develop diabetes, and both conditions
are on the rise.
The new findings, published in the journal Cell, offer
another explanation of exactly how the two are linked.
"We have discovered ... a molecular trigger which begins
the chain of events leading from hyperglycemia to insulin
resistance and type 2 diabetes," said Jamey Marth, a professor
of cellular and molecular medicine at the university.
"This finding suggests new approaches to the prevention
and treatment of diabetes," said Marth, an investigator
with the nonprofit medical research organization Howard
Hughes Medical Institute, which helped fund the research.
Marth and his colleagues studied the glycosyltransferase
enzyme (GnT-4a), which helps the pancreas sense how much
sugar is in the blood and release enough insulin to help
process it.
In a study of normal mice that were fed a fatty diet,
researchers found that the enzyme was repressed, leaving
pancreatic cells unable to sense sugar levels and leading
to diabetes.
"Our findings suggest that the current human epidemic
in type 2 diabetes may be a result of GnT-4a enzyme deficiency,"
said Marth, adding that people who inherit a faulty gene
that controls the enzyme may also be vulnerable to diabetes.
It may also play a role in the early onset of type 2
diabetes in children and teenagers, according to the study,
which was also sponsored by the
National Institutes of Health.
The researchers are now looking at ways to boost the
enzyme in hopes of staving off diabetes.
Earlier this year, European researchers said they found
a gene, called ENPP1, that helps control how cells respond
to insulin. In 11 different variations of the gene, six
were linked to severe obesity, they reported.
Researchers at Beth Israel
Deaconess Medical Center in Boston have also discovered
a substance called retinol binding protein (RBP4) that
is released by fat tissue and can cause insulin resistance.
Their finding was reported in the journal Nature in July.
