One of the functions of your kidneys is to remove waste products and extra fluid from the blood. Waste products come from your diet and normal breakdown of tissues. The kidneys filter about 50 gallons of blood a day. Of that amount, about one-half to two quarts of fluid and waste products are removed from the blood and passed out of the body in urine.

The urinary system is made up of two kidneys; two ureters, which are thin tubes that carry urine from the kidneys to the bladder; the bladder, which stores urine; two sphincter muscles that prevent urine from leaking; nerves in the bladder; and the urethra, which is the tube that carries urine outside the body. The kidneys not only remove liquid waste from the blood, but also regulate electrolytes, or minerals; secrete hormones that control blood pressure; stimulate red blood cell production; and help maintain calcium balance.

High blood pressure and uncontrolled diabetes (high blood sugar over long periods of time) can damage the kidneys' small blood vessels so they are unable to filter blood. This can eventually cause kidney failure. Diabetes and hypertension are the leading causes of kidney disease. The most common reason for a kidney transplant is the long-term effects of diabetes.

Each kidney contains about a million tiny filtering units called nephrons. A nephron is made up of small tubes and blood vessels. Diseases that affect the kidneys can damage the nephrons. As a result, the kidneys have problems getting rid of waste products.

African-American men ages 20 to 29 are 10 times more likely to develop kidney failure as a result of high blood pressure than Caucasian men in the same age group. That risk increases 14 times in men ages 30 to 39.

According to the National Kidney Foundation, these over-the-counter pain relievers present no danger for most people when taken according to directions. For people with certain health conditions, however, these medications may cause kidney problems. In addition, if you take these medications regularly over a long period of time, you may increase your risk for kidney problems. Talk with your health care provider about these medications and find out what is best for you.

According to the National Institute of Diabetes and Digestive and Kidney Disease, people who have decreased function of their kidneys may need to monitor the protein in their diet. Sodium, found in salt, may raise your blood pressure. High blood pressure can damage the kidneys. Talk with your health care provider to be sure you’re getting the proper nutrition, as well as making the appropriate changes in your diet to help your kidneys work well.

Calcium kidney stones are two to three times more common in men than women. Diet or disease in the small intestine usually causes them.