All you should know about kidneys.

• Position: Special Newsletter Edition: Your Health

How much do you know about how your kidneys work, how disease may affect them, and how to prevent kidney disease? The National Kidney Foundation provides the following information about these vital organs:

The kidneys' main job is to filter waste products and excess fluid from the blood. Each day, they filter around 200 quarts of fluid. About two quarts leave the body in the form of urine, while the rest is retained in the body. The kidneys also release hormones that help regulate blood pressure, control the production of red blood cells, and produce vitamins that affect growth.

When they no longer perform these functions adequately due to injury or disease, wastes and excess fluid build up in the blood. The early warning signs that your kidneys may not be working well are burning or difficulty during urination; needing to urinate more often than usual, especially during the night; blood in the urine; puffiness or swelling of hands or feet; pain in the back or side below the ribs; and high blood pressure.

The two leading causes of end stage kidney disease, which requires regular dialysis or transplantation to stay alive, are diabetes and high blood pressure. When these are controlled by treatment, the associated kidney disease often can be prevented or slowed down. Many effective drugs now are available to treat high blood pressure. In addition, healthy lifestyle changes, such as losing weight and regular exercise, often help to control--and may even...