Some of the good diets to improve the function of a severe damaged kidney include rice, foods with red bell peppers, Cabbage, Cauliflower and Garlic, Fruits such as apples, berries, grapes, peaches and pineapple. These foods also help to neutralize free radicals and protect the body. Check out http://www.livestrong.com/article/539447-diet-for-damaged-kidneys/ for more particulars.
You can promote kidney health by avoiding high levels of sodium, potassium and protein in your diet. Instead, should choose foods that provide the same benefits without any of the items that are bad for your kidneys