Can Grapes Prevent Type 1 Diabetes?

Researchers have for the first time determined that some component of table grapes prevented the progression of type 1 diabetes in mice and increased their survival. Susan Zunino’s experiment apparently is the first to show a link between eating grapes and preventing progression of type 1 diabetes. That was in contrast to diabetic mice that were not fed grapes.

Susan J. Zunino, an Agricultural Research Service molecular biologist, working with Storms and Charles Stephensen, a physiologist at the Davis research center, conducted the research.

Scientists provided the fruit in the form of a freeze-dried powder made from table grapes, the kind sold fresh in the produce section of supermarkets.

The powder, provided by the California Table Grape Commission, made up 1 percent of the chow fed to some of the mice. That’s the human equivalent of about six servings of grapes per day.

At present the researchers don’t know which grape compounds provided the protective effect.

Similarly, the exact sequence of steps that led to the protection is also not yet proven. But the scientists think that the grape phytochemicals may have prevented unwanted entry of immune cells into the pancreas.

Mice fed the grape powder had fewer immune cells in the pancreas than did the other mice in the experiment.

But what’s the relation between immune cells in the pancreas and type 1 diabetes?
Immune cells in the pancreas can mistakenly attack specialized cells known as “beta cells.” Beta cells produce insulin, which is needed to help regulate the amount of sugar in the bloodstream. If immune cells in the pancreas attack and kill beta cells, the pancreas can run out of beta cells. When that happens, type 1 diabetes can result.

People with type 1 diabetes have to carefully monitor the amounts of sugar-containing foods they eat, including sweet, fresh table grapes. How ironic that this luscious fruit might actually hold a key to preventing the progression of type 1 diabetes. This may be a perplexing riddle of Nature - perhaps one that Zunino’s team will soon solve.

According to the National Institutes of Health, an estimated 1 in every 400-600 children and adolescents in the U.S. population has type 1 diabetes.

If the results from this study of 30 laboratory mice hold true for humans, the research could offer new options for protection against this chronic autoimmune disease.

Reference:
By Marcia Wood, Agricultural Research Service Information Staff, USDA-ARS. Photo courtesy USDA, ARS.

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