They found that middle-aged rats fed a diet low in Vitamin D developed free radical damage to the brain. In addition, there was a “significant decrease” in tests on learning and memory. Vitamin D deficiency is very common among elderly Americans. Researchers think that vitamin D supplementation may help protect against cognitive decline in adults.

This is the first study to show that a diet that is chronically low in Vitamin D alerts glucose metabolism and change the mitochondria (the power source) of cells in the brains of elderly rats. This deficient diet also causes significant increases in tyrosine nitration in brain proteins. Tyrosine nitration occurs under disease conditions. This can lead to the development of nitrotyrosine, a compound found in the brains of people with degenerative and neurological disorders.