Drinking plenty of fluid will help your kidneys function properly. Your urine should be straw-colored. If it’s any darker it may be a sign of dehydration. Including fresh juices is another way of drinking more fluids and keeping your kidneys healthy. Juices help the digestive system to extract more water and flush out wastes from the body. Avoid drinking coffee and tea. They contain caffeine which reduces the amount of fluids in the body. So, the kidneys have to work harder to get rid of them.