Purina Pro Plan Veterinary Diets NF Kidney Function Canine Formulas are made with a restricted amount of high-quality protein and restricted phosphorus. The science behind our therapeutic diets represents a collaboration between Purina pet nutrition experts, researchers and veterinarians. Medical Indications: Diets with these nutritional modifications have been recommended for dogs with the following conditions: • Chronic kidney disease • Hepatic disease associated with encephalopathy • Conditions benefitting from moderate sodium reduction