Study leader Deborah Muoio of the Duke University Medical Center's Sarah W. Stedman Nutrition and Metabolism Center said carnitine reverses glucose intolerance in animals.
Muoio also performed tests on human muscle cells that showed supplementing with carnitine might help older people with pre-diabetes, diabetes and other disorders that make glucose metabolism difficult.
The researchers said that after eight weeks of supplementation with carnitine, the obese rats restored their cells' fuel-burning capacity, which was shut down by a lack of natural carnitine, and improved their glucose tolerance -- a health outcome that indicates a lower risk of diabetes. Carnitine is made in the liver and recycled by the kidney, but in some cases it is insufficient, Muoio said.
The study is scheduled to be published in the Aug. 21 issue of the Journal of Biological Chemistry.