Your kidneys are two bean-shaped organs, each about the size of your fists. They are located near the middle of your back, just below the rib cage. Inside each kidney about a million tiny structures called nephrons filter blood. They remove waste products and extra water, which become urine. The urine flows through tubes called ureters to your bladder, which stores the urine until you go to the bathroom. Most kidney diseases attack the nephrons. This damage may leave kidneys unable to remove wastes. Causes can include genetic problems, injuries, or medicines.kidneys remove waste matter and regulate the blood pressure and salt balance. When the kidneys don't function properly, symptoms such as swelling, excess urination, shortness of breath and cardiovascular difficulties arise. If these problems are ignored, renal failure may set in leading to heart disease or even death. Along with the many treatments available to fight kidney disease, you can be proactive and follow a renal diet, eating certain foods that support healthy kidney function.