The kidneys filter waste products from the blood and send them out of the body in the urine. They are also responsible for balancing fluid and electrolyte levels. The kidneys perform these tasks with no outside help. Several conditions, such as diabetes and high blood pressure, may affect their ability to function.Following a kidney-healthy diet plan may help the kidneys function properly and prevent damage to these organs. However, although some foods generally help support a healthy kidney, not all of them are suitable for people who have kidney disease.