Depression affects as many as 25 percent of diabetes sufferers, and new research has found a possible cause in the form of high levels of glutamate, a neurotransmitter in the brain produced from glucose.

Researchers from the Joslin Diabetes Center and other institutions have shown that increased levels of glutamate in the prefrontal area of the brains of people with type 1 diabetes were linked with symptoms of depression and lower scores on tests of cognitive function.

They also established that high levels of glutamate are due to poorer glucose control resulting in abnormal blood sugar level, typical of those with diabetes.

"The importance of [these findings] lies in the linkage of a neurotransmitter that, in high levels, can cause damage to neurons, the degree of diabetic hyperglycemia and alterations in cognitive function and depression levels previously found in diabetes," says Dr. Alan Jacobson, chief of psychiatry at Joslin Diabetes Center.

They also open the possibility of developing new treatments for depression in diabetics by altering the transmission of glutamate.

As scientists continue their work, there are a number of natural health resources people can use to manage their depression, and they include exercise and a healthy diet as well as nutritional supplements containing fenugreek, bitter melon or cinnamon that may help lower the levels of glutamate in the body.