Low protein to carbohydrate ratio diet delays onset of Parkinsonism like phenotype in Drosophila melanogaster parkin null mutants

Dietary management plays a key role in the treatment of many diseases. However, no prospective studies have critically investigated the potential for dietary modification to delay the onset, or slow the progression, of Parkinson's Disease (PD). To study whether manipulating the Protein to Carbohydrate (P:C) ratio in the diet could affect the progression of PD, we compared Drosophila melanogaster parkin null mutants and their experimental controls fed with diets differing in their P:C ratio. We considered lifespan and feeding behaviors as well as motor and cellular functions on the 1:2 and 1:16 P:C diets. We observe that parkin mutants have a longer lifespan when fed the 1:16 P:C compared to those fed the 1:2 P:C diet. Parkin mutants fed the 1:16 P:C diet have delayed climbing deficit, increased resistance to starvation. Mutant flies fed the 1:16 P:C diet also have improved mitochondrial functions as evidenced by increased respiratory control ratio and mitochondrial membrane potential and decreased reactive oxygen species production and superoxide activity especially in old parkin mutants. Combined, these results suggest that dietary management has potential to delay the progression of PD.