Your Kidneys: Ten Tips on How They Help Keep Your Body Healthy

Your kidneys may be small, but they perform many vital functions that help maintain your overall health, including filtering wastes and excess fluids from your blood. Chronic kidney disease may lead to complete kidney failure and the need for dialysis treatments or a kidney transplant to sustain life. While effective treatments are available for many chronic kidney diseases, many people are unaware that chronic kidney disease can often be prevented. Here are ten important facts about how your kidneys work, how disease may affect them, and how you can prevent chronic kidney disease.

  1. Your kidneys are about the size of your fist. They are located in the back, just below the rib cage. The kidney's main job is to filter waste products and excess fluid from your blood. Every day, the kidneys filter about 200 quarts of fluid. About two quarts leave the body in the form of urine, while the remainder is retained in the body.
  2. In addition to filtering wastes from the blood, the kidneys also perform these important jobs:
    • release hormones that help regulate blood pressure;
    • control the production of red blood cells;
    • make vitamins that control growth.
  3. When the kidneys 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:
    • high blood pressure;
    • blood and/or protein in the urine;
    • BUN and creatinine blood tests outside the normal range 1
    • glomerular filtration rate (GFR), less than 90 2
    • more frequent urination, particularly at night; difficult or painful urination
    • puffiness around eyes or swelling of hands or feet
  4. Anyone can develop chronic kidney disease, but some people have an increased chance of developing kidney disease. This includes those who:
    • have a family history of kidney disease
    • have diabetes
    • have high blood pressure
    • are older
    • are African American, Hispanic American, Asian American or American Indian.
  5. In the U.S., the two leading causes of kidney failure-- which requires regular dialysis or transplantation to sustain life-- are diabetes and high blood pressure. When these two diseases are controlled by treatment, the associated chronic kidney disease can often be prevented or slowed down.
  6. Many effective drugs are available to treat high blood pressure. In addition, healthy lifestyle changes, such as losing excess weight and regular exercise, often help to control -- and may even help to prevent -- high blood pressure.
  7. Careful control of blood sugar in diabetics helps to prevent complications including chronic kidney disease, heart problems and strokes. When diabetics have associated high blood pressure, special drugs called angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) may help to protect their kidney function.
  8. The third leading cause of kidney failure in the U.S. is glomerulonephritis-- a disease that damages the kidney's filtering units, called the glomeruli. In many cases, the cause of this disease is not known, but some cases may be inherited and others may be triggered by an infection.
  9. Some of the other conditions that may affect the kidneys include kidney stones and inherited diseases such as polycystic kidney disease. Some of these diseases can be cured. In other cases, treatments can help to slow the disease and prolong life. The kidneys can also be harmed by overuse of some over-the-counter pain killers and by taking illegal drugs such as heroin.
  10. Kidney failure occurs when 85 to 90 percent of kidney function has been lost. Doctors can determine when patients reach this stage on the basis of blood and urine tests. Patients may experience nausea, vomiting, weakness, fatigue, confusion, difficulty concentrating and loss of appetite.

More than 20 million Americans have chronic kidney disease. Another 20 million are at increased risk for developing kidney disease, and many are not aware of it. Kidney disease may be silent in the early stages. It's important for doctors to include blood and urine tests that check the kidneys as part of regular medical checkups. Early detection and treatment may help to prevent chronic kidney disease from worsening. The National Kidney Foundation and its 51 Affiliates with more than 200 chapters nationwide comprise the major voluntary health organization in the U.S., whose purpose and efforts are directed solely to the eradication of kidney and urologic diseases.

  1. BUN and creatinine are wastes that build up in the blood when your kidney function is reduced.
  2. GFR (a measure of kidney function) is estimated from a blood creatinine test. In some people, a GFR of 60 to 89 may be normal.

January 2003