Bert Lance, who worked for Jimmy Carter in the Budget office, is credited with saying, “If it ain’t broke, don’t fix it,” as cited in the May 1977 issue of the magazine Nation’s Business. Sometimes we carry this admonition too far, as when we ignore body parts that don’t hurt. Not everything that’s out of order lets us know right away. It’s a lot easier to prevent damage than to fix it; just as changing the oil in your car prevents an exorbitant repair bill. The same applies to your body. Preventing ailments is easier and less painful than fixing them. Except for stones, the kidneys pretty much mind their own business, seldom letting us know they’re even there. A little maintenance goes a long way. Many people don’t even know where in the body they are or what they do.
These bean-shaped organs, about the size of a fist, are near the middle of the back, just below the ribs, one on each side of the spine. And, boy oh boy, are they sophisticated reprocessing machines. They handle nearly fifty gallons of blood a day to filter about a half gallon of waste and excess water, which you already know is stored in the bladder. The wastes come from food leftovers that float in the blood after the food’s energy supplies have been used. If these wastes weren’t removed, they’d make us sick. The actual removal of the impurities occurs in the nephrons, which are the functional units of the kidney. Each kidney has more than a million nephrons, which have tiny blood vessels that help to remove the junk, including urea, uric acid, creatinine from muscles, and excess electrolytes. Normal proteins and other materials are kept in the bloodstream to be recycled for use by the body. This includes potassium, phosphorus and sodium, among others. The kidneys also release three vital hormones—erythropoietin to stimulate the marrow to make red blood cells, renin to control blood pressure, and calcitriol (the active form of vitamin D) to help maintain calcium for bones.
If kidney function were to fail by as much as thirty percent, you probably wouldn’t even know it. That’s one of the reasons why it’s measured on blood tests, looking at creatinine, glomerular filtration rate (GFR) and blood urea nitrogen (BUN). The first of these comes from normal wear and tear on muscles; the second is an age-variable measure of how well the kidneys filter the wastes; and the third is a product of protein breakdown from the foods you eat. Proteins can also be monitored via urine. It is possible to survive with only one kidney, but living with two is nicer. If function drops to fifteen percent, either dialysis or a transplant may be necessary to sustain life.
There are things we can do to prevent kidney disorders. If there is a family history of diabetes or high blood pressure, tend to those right away. Glucose that stays in the blood instead of getting used for fuel can damage the nephrons. High BP distresses the tiny blood vessels of the nephrons, interfering with their function. Yes, there are medications to address these problems, but there also are a few dietary interventions that can keep the kidneys healthy.
Keeping sodium under control is necessary, especially as we age. Processed meals and meats contain large amounts of sodium, but so do restaurant foods, fast foods, soups and snacks. In some who are susceptible, sodium may spike BP.
The same oxygen that gives us life takes away molecular stability in the form of free radicals, which take turns stealing electrons from each other in a continuous cycle. Some come from the environment as pollution, and some from inside the body from burning food for energy. Supplying both the fat-soluble and water-soluble anti-oxidants from supplements is a good start, but that does not rule out the importance of the right diet, from which you can make the master anti-oxidant, glutathione.
Too much protein can tax the kidneys, particularly animal proteins. Mixing plant and animal sources is a safe bet. Whole grains and legumes can help. Depending on the condition of the body, however, protein intake in excess of protein need may or may not adversely affect the kidneys (Martin, 2005) (Knight, 2003). In the presence of a jeopardized kidney, elevated phosphorus levels can do harm. Meats and dairy are main sources, but food additives also contribute to the load. Phosphorus is an essential element in the diet, and in the form of phosphates is a major component of bone. It’s necessary for the manufacture of adenosine triphosphate to be burned for energy. Without it, metabolism of calcium, protein and glucose is upset. But an excess burdens the filtration load of the nephrons, and phosphate retention is linked to parathyroid malfunction.
Now, what do we eat? Reducing sodium intake is simple. Just do it. More than 500 mg at a meal is pushing it, so you have to read labels. Canned soups can give you half a day’s worth in a single serving. You can swallow anti-oxidants from a bottle, but it’s helpful to get some from food. Berries are an excellent source, as are peppers, squashes and tomatoes. Cruciferous vegetables supply vitamin C, while onions offer quercetin, an anti-oxidant bioflavonoid that is also cardio-protective. Apples, with skins, are anti-inflammatory. Egg whites are a source of complete protein, having all the essential amino acids and less than a dozen milligrams of phosphorus. The omega-3 fats from cold-water fish—and from fish oil—can’t be beat for anti-inflammatory work (see http://oilofpisces.com/kidneydisorders.html) and olive oil is rich in polyphenols that inhibit inflammation and oxidation. A reliable research link for the study of kidney health is DaVita Clinical Research, http://www.davitaclinicalresearch.com/overview-mission.asp.
Water is an essential nutrient. Though we think that more is better, the truth is that more can be toxic. Drink too much and the kidneys can’t keep up. The cells get swollen beyond their capacity, sodium levels drop precipitously, and the firing of neurotransmitters short circuits, leading to headaches, fatigue, disorientation and even death. Thinking water will reduce protein blood test values, some people will overdo water intake and find that all they have done is dilute the protein. Even endurance athletes need to balance water intake with water loss.
A little prevention costs less than a plumber.
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