All About Kidneys

What They Do for Us and What We Can Do for Them

Our kidneys are one of the essential organ systems; we cannot survive if their job is not done. What makes them so important? When functioning properly, they keep our systems in balance. When they stop working, the result is called kidney or renal failure. (Note that the Latin term renal, meaning kidneys, is used interchangeably in medicine, as if things were not already confusing enough!) Life ends, unless dialysis or a kidney transplant is done. Prior to the mid-twentieth century, when these two procedures were developed, renal failure was a death sentence. Mozart, Emily Dickinson, and President Chester A. Arthur all succumbed to this. And, since there is still no cure for advanced kidney disease, prevention is your best option.

One crucial role of the kidney system is to keep a stable amount of water in the body. Too much and the heart is overloaded and the lungs fill with fluid. They are then unable to absorb oxygen. Not enough and circulation slows, depriving all organs of necessary oxygen and nutrients. Healthy kidneys need a certain amount of water to perform all of their amazing jobs and easily excrete the exact right amount of unnecessary water as urine. If we have a fluid shortage, however, they cannot work properly and can suffer irreversible damage. So one of the basic ways to promote kidney wellness is to drink a good amount of water. Men should take in at least 3 liters of fluid per day, women at least 2.2 liters. Note that diuretics, like alcohol and coffee, cause the kidneys to put out more fluid that they take in, so they don’t count as helpful fluid intake.

Another critical task the kidneys do is get rid of urea nitrogen, a toxic particle in the body, which is left over from protein metabolism. This is a deadly substance if present in high concentrations. In fact, kidney failure used to be called “uremic poisoning.” Doctors easily monitor the health of the renal system by checking levels of this substance using a routine blood test. Adequate water intake helps the kidneys excrete urea nitrogen, but it is also very important that you do not overload on protein, particularly synthetic/powdered types, as this will overstress the kidneys’ detoxifying ability. High-dose protein supplements, like those touted for body building, can be very damaging. Sticking to natural sources of protein, like lean meats, eggs, milk, beans, and nuts will ensure you are not overtaxing this system.

Sodium (salt), potassium, calcium, phosphorous, and chloride are the major minerals in your system. They are integral to normal cell function in every organ. Even slight imbalances can have a devastating effect on your health. The kidneys are able to stabilize levels via an elegant machinery that results in holding on to minerals if their levels start to run low and discarding extra minerals if the levels start getting too high. You can help your kidneys stay fit by making sure you have an adequate amount of these key minerals in your diet. Fresh fruits and vegetables are a wonderful source. Athletic drinks, such as Gatorade, are also very helpful when hydration needs are high, such as during strenuous exercise or when suffering from a stomach bug. Relying only on plain water during these situations can cause a shortage of minerals and strain kidney function.

Lastly, although many folks do not realize it, it’s the kidneys, not the heart, that regulates blood pressure. Kidneys have highly responsive sensors in the walls of their blood vessels and filtration tubes that detect current pressure and trigger changes, if it is not ideal. They do this mainly by adjusting the level of a kidney-produced enzyme called renin. If the blood pressure is too low, extra renin is put out. This activates a body-wide system to get the pressure back up. Elevated blood pressure has the opposite effect. It causes the kidneys to reduce renin production. But this system is limited in its ability to maintain perfect blood pressure indefinitely if other factors work against it. And if high blood pressure is beyond the ability of the kidneys to auto-regulate, the increased stress on the many delicate arteries and filtration tubules in the kidneys will cause scarring. This system will then not be able to perform all of its important jobs, even its ability to help control blood pressure will be ruined. This is why uncontrolled high blood pressure is the second most common cause of kidney failure. It also reveals why controlling blood pressure, sooner rather than later, is paramount to good kidney health.

We should love our kidneys. They detoxify our body, they balance water and minerals, and they help keep our blood pressure where it should be. Be kind to these wondrous organs by making sure to drink enough fluid every day and by eating a diet rich in fruits and vegetables while moderating protein intake. Be sure to have your blood pressure checked at least once a year and more frequently if there is a problem. Take medication to help control levels, if advised. Normal renal function is crucial to a long and happy life. The efforts you make to keep your kidneys healthy are a valuable investment in your future.

Patrice Thornton, MD, is a primary care physician at SVMC Northshire Campus in Manchester. She is accepting new patients.