More than 29 million Americans have diabetes, and about half of them suffer from nerve damage or neuropathy. There is no cure, and the most effective treatment, which is keeping blood sugar levels under control, doesn't stop but only slows the painful condition.

A new study conducted at the VA Medical Center in Iowa City, however, found that Resolvin D1, a metabolite produced by an omega-3 fatty acid found in fish, not only stops the progression of neuropathy in mice, but actually reverses it.

"Diabetic neuropathy is a very costly and debilitating complication of diabetes," researcher Mark Yorek said in a news release. "It is the leading cause of foot ulcers and nontrauma-related amputations, and the impact of diabetic neuropathy on the patient and family are unmeasurable."

Fish oil supplements, Yorek said, would be a safe treatment. "Supplements are considered very safe and could be easily translated into everyday care.

"Fish oil would be easy to take, like a vitamin, and should have few side effects when combined with other medications," he explained.

Numerous previous studies have found that the omega-3 fatty acids found in fish oil help diabetics manage blood sugar levels better, reduce inflammation, and improve liver function.

In the new study, diabetic mice were given high-fat diets and daily injections of resolvin, a metabolite produced in the body from fish oil, or a high-fat diet in which half the fat came from fish oil. The results were compared to healthy, non-diabetic mice.

The diabetic mice had less feeling in their paws and their eyes had fewer nerves. But even though fish oil diets and resolvin didn't lower sugar levels to a normal range, they improved the amount of feeling in the animals' paws. Resolvin also stimulated nerves to grow.

"Even though a lot more work needs to be done, including clinical trials with human subjects, our animal studies suggest that fish oil can reverse some of the harmful effects of diabetes on the nerves," Yorek said.