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Tuesday, June 18, 2013
The kidneys are two main organs of the urinary system. They rid the body of wastes caused by use of the muscles and by the digestion of foods and liquids. The kidneys filter out harmful toxins, pull out excess water, and re-circulate beneficial components such as proteins. Unfortunately, the urinary system is very delicate and can be damaged by chemical imbalances caused by disease, particularly hypertension (high blood pressure)and diabetes. Diabetes is a disorder involving imbalances in insulin and sugar. In fact, diabetes is the leading cause of kidney
|In African Americans, diabetes accounts for 39% of all cases of treated kidney failure and high blood pressure for 34%.1|
|Among whites treated for kidney failure, 40% of the cases result from diabetes and 25% from high blood pressure.1 These numbers show that high blood pressure is a more common cause of kidney failure in African Americans than it is in whites. However, diabetes is still the number one cause of kidney failure in African Americans.|
For more statistics about diabetes in African Americans, click here
The number of new kidney failure cases diagnosed in 1997 was 873 per million in African Americans and 218 per million in whites. This means that African Americans are 4 times as likely as whites to develop kidney failure. The risk of kidney failure as a result of high blood pressure is about 6 times greater in African Americans than in whites.1
Although African Americans make up 13% of the U.S. population, they account for 30% of all kidney failure cases.
Given that African Americans tend to have higher rates of hypertension and diabetes, one would expect a higher rate of kidney disease. In truth, research shows that something beyond hypertension or diabetes places African Americans-regardless of age or gender-at significantly higher risk for kidney disease than non-African Americans. Although genetic differences in races are clearly recognized by researchers, how these differences came about is unknown. If you are African American, you are in a group at higher risk for hypertension. It is therefore important to take measures to reduce your chances of getting kidney disease.
1United States Renal Data System 1999 Annual Report (Am J Kidney Dis 34:2[suppl 1],1999).
Hypertension causes unwanted changes in the arterial blood vessels, the vessels that route blood from the heart to the rest of the body. Like the rest of the arteries, those supplying blood to the kidneys are more rigid than normal. This increased pressure forces certain proteins into the filtering system housed in the nephrons, the key units of the kidney. Under normal conditions the proteins would not get inside the nephrons; but when they do, the body's immune system treats them as "unfriendly" and mounts an attack against them. This immune response causes destruction of the normal nephron. Keeping the blood pressure in the normal range-through diet, exercise, relaxation, and medication-can significantly reduce the risk of damage to the nephrons.
One way to significantly reduce the risk of developing kidney disease is to maintain a healthy diet. For example, a diet rich in red meat-which means a diet that has high levels of protein-can harm the kidneys. When the liver processes this protein it sends smaller proteins back into the circulation and eventually they end up having to be filtered by the kidneys. This accumulation of protein in the kidneys overloads the body and causes an immune response like the one mentioned above. Therefore, keeping the amount of red meat in the diet at a low level helps reduce kidney damage.
In 1998, approximately 4 out of every 100 African Americans were diagnosed with diabetes. Today, the number of diabetics in African Americans is double that of white Americans. Diabetes accelerates hardening of the arteries and in turn is associated with high blood pressure, strokes, and kidney disease. There are now simple tests to determine if an individual has diabetes and many forms of treatment that will prolong a productive life. To learn more about diabetes, click here.
In addition to skin, muscle, and bones, the body consists of many complex organs that work together to keep us functioning normally. Several of these organs perform "housekeeping" functions, ridding the body of wastes and toxins that could make us very sick if they were not constantly cleared out of our systems. The kidneys, located near the middle of the back and just below the rib cage, play this role by removing harmful wastes that accumulate in the blood. They also remove excess water and sodium. (The end-product of all this filtering and removal is the fluid known as urine.)
Day in and day out, these bean-shaped organs (each about the size of your fist) process the equivalent of roughly 200 quarts of blood in order to remove 2 quarts of waste products and extra water. For more on how the kidneys work, click here. The entire process relies on a complex filtering system housed inside the kidneys. The key unit of this system is the nephron, a tiny structure made up of an intricate web of intertwined capillaries (tiny blood vessels), tubules (one of several nephron filtering components), and other structures. It is this system that, in addition to performing crucial filtering functions, removes wastes from the blood.
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Last Reviewed: Sep 18, 2001
Max C Reif, MD
Professor of Medicine
Director of Hypertension Section
College of Medicine
University of Cincinnati