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Kidneys filter, cleanse and regulate

  By: Kenneth Ripp, M.D.

Your kidneys rest in the back of the abdominal cavity, one on each side of the spine, just above the waist and just below the liver and pancreas. These important organs are about the length of your fist – four to five inches long – and about one-inch thick. They weigh about 5 ounces each.

As long as they are functioning properly, chances are you don’t give your kidneys a whole lot of thought. It is important to note, however, that your kidneys are responsible for filtering your body’s entire blood supply – about 20 times each day.

During the filtering process, the kidneys remove waste and regulate the chemical composition of the blood, which includes a number of different functions. For instance, the kidneys release three hormones into the blood: erythropoietin (EPO) stimulates bone marrow to make red blood cells; rennin regulates blood pressure; and calcitiriol, which helps maintain calcium. The kidneys also regulate the concentrations of ions ad other substances in the blood. They keep the volume of water in the body constant and regulate the acid/base concentration of the blood.

All this work is done within tiny units called nephrons. Each kidney has about a million nephrons, which are composed of a filtering component (renal corpuscle) and a tubule specialized for reabsorption and secretion (renal tubule). Nephrons work to regulate water and soluble substances – such as sodium, phosphorus and potassium – by filtering the blood, removing waste, reabsorbing substances that are needed and excreting the rest as urine.

Although the kidneys constitute only about half of one percent of your total body weight, the functions they perform are vital to your health. Disease can cause the kidneys to function at less than 100 percent. Small or mild declines in function – 20 to 30 percent – would rarely be noticeable. In fact people are able to function normally with 50 percent kidney function. Some people are born with only one kidney; others lose a kidney to disease or injury and are able to lead normal, healthy lives.

Kidney disease often attacks gradually. That is, you may lose kidney function slowly and not even be aware of the change. It isn’t until kidneys are functioning at 25 percent that serious health problems occur. When kidney function drops below 10 to 15 percent, a person needs some sort of renal replacement therapy – either dialysis or a transplant.

The two most common causes of kidney disease are diabetes and high blood pressure. People with a family history of kidney problems are also at increased risk.

Symptoms of kidney disease (often not present until kidneys have lost a significant amount of overall function) are: the need to urinate more or less often, fatigue, loss of appetite, nausea, vomiting, swelling of the hands and feet, itching, numbness, difficulty concentrating, darkened skin and muscle cramps.

Kidney disease can be detected through a urine analysis and/or blood test. Your primary care physician can provide you with more information about diagnosing kidney disease.

The best way to deal with kidney disease is to avoid it but choosing lifestyle habits that reduce the workload you place on your kidneys. Ways to do this:

Drink enough water. This helps keep your kidneys flushed of excess acid. If your urine is dark yellow in color, you aren’t drinking enough water.

Eat kidney-friendly foods. This includes fresh fruit (such as apples, cranberries, other berries and red grapes), fresh vegetables (good choices include onions, garlic, red bell peppers, cabbage and cauliflower), whole grain fiber, egg whites, fish and olive oil.

Avoid or limit foods that can tax the kidneys: salty foods, fried foods, processed fats, caffeine, sugar and processed carbohydrates. Cut back on protein, especially red meat.

Cut down on big, heavy meals and opt for more frequent, lighter fare.

Exercise can lower blood pressure and help prevent type II diabetes – two leading causes of kidney failure.

Detoxification – or removing toxins from your body. Limit intake of alcohol and drugs (even over-the-counter medications are filtered through the kidneys). Don’t smoke. Avoid breathing polluted air.

Reduce stress and get enough sleep.

Your kidneys rest in your abdominal cavity, one on each side of the spine. But resting is far from what your kidneys do. These hard-working organs cleanse and regulate your body’s blood supply to remove waste and regulate chemical composition. They filter your entire blood supply about 20 times each day. That’s no small feat, but it’s all in a day’s work for these organs that are slightly bigger than your cell phone.

It is estimated that 26 million Americans (one in nine adults) have chronic kidney disease. Keep yourself from being part of this statistic by choosing lifestyle habits that increase the likelihood of your own kidney health. If you suspect a problem with your kidneys, consult your primary care physician..


Dr. Ripp is a board certified family practice physician at Raiter Clinic.