Potassium Carries the Signals That Keep You Alive

The Explosive Nutrient We All Need

These are rarely seen samples of pure potassium (actual size on most 17-inch monitors). The amazingly lightweight metal (it floats on water) was first extracted from potash in 1807 by British chemist Sir Humphry Davy. To see what happens if you drop one of these samples in water, click here. (Photo from Encarta.)

By Terry Dunkle, DietPower CEO

Although potassium is one of the most important nutrients in your body, it's cheap as dirt. In fact, every cup of soil in your back yard contains a teaspoonful of the shiny white metal—roughly the amount you need every day. You can't see the potassium, however, because of this element's violent relationship with water.

When you drop a chunk of potassium into water, it bursts into a lilac flame that fizzes, pops, and skitters around the surface. (Click to see.) Because it oxidizes so readily, pure potassium must be stored in argon or mineral oil.  The potassium in your back yard has long since disintegrated into a fine gray dust known as potassium nitrate, or "potash." Farmers use it for fertilizer, terrorists to make bombs.

You would think that a nutrient so powerful would have powerful effects on your body—and so it does, for potassium provides the negative charge in the tiny battery inside every living cell. Without potassium, your heart, brain, nerves, and muscles couldn't transmit, carry, or receive electrical signals, and you would instantly die.

Terry Schiavo's problem has been attributed to a potassium deficiency.

You might also think people would take pains to get enough of this vital nutrient—but they don't. The average American gets only half the recommended amount.

Some people can get away with poor potassium intake for years. Don't press your luck, however, if you belong to any of the following groups.

You Probably Need More Potassium if...

...you have high blood pressure. A potassium deficit can aggravate hypertension, increasing heart-attack and stroke risk. That's why the United States Food and Nutrition Board recently raised the daily recommendation for potassium from 3500 milligrams to 4700. (For lactating women it's 5100). In one major study, increasing daily intake by 2000 milligrams lowered blood pressure by several points.

...you like salt. Potassium tends to counteract the rise in blood pressure from excess sodium intake. (Most people get too much sodium—see "Give Me Liberty or Give Me a Stroke!") The more sensitive your blood pressure is to salt, the greater potassium's ability to blunt the effect. ...you're black. For reasons still only poorly understood, people of African descent are more prone to high blood pressure and salt sensitivity than other ethnic groups. They also get  less potassium  on  an  average

To get your 4700 milligrams a day, you can either swallow all 52 of these potassium gluconate tablets or eat plenty of vegetables, fruits, potatoes, peanut butter, and nuts.

day than whites, latinos, and Asians do—typically 500 to 700 milligrams less. In addition, taking extra potassium, whether from food or supplements, seems to lower black people's blood pressure more than it does other people's.

...you don't want kidney stones. This painful malady often results from a too-acidic diet. Foods rich in potassium (pictured above) tend to neutralize acids. Two studies have linked higher potassium intake with lower kidney-stone risk.

...you don't want osteoporosis. Excess acid in the blood tends to leach calcium out of the bones. Studies show that supplements of potassium bicarbonate can reduce bone breakdown and increase bone formation.

...you like meat. High-protein diets are a leading cause of high blood acidity.

You May Need Less Potassium if...

...you take certain drugs. Getting too much potassium is rare, because the kidneys excrete any excess into the urine. (Symptoms of potassium overdose, or hyperkalemia, include irregular heartbeat and muscle paralysis.) Nevertheless, three classes of drugs—prescribed for high blood pressure and related ailments—can impair potassium excretion:

• Angiotensin converting enzyme (ACE) inhibitors, such as captopril (Capoten), enalapril (Vaseretic), benazepril (Lotensin), and perindopril (Aceon).

• Angiotensin receptor blockers (ARB), such as irbesartan (Avapro, Avalide), eprosartan (Teveten), telmisartan (Micardis), candesartan cilexetil (Atacand), losartan potassium (Cozaar, Hyzaar), olmesartan (Benicar), and valsartan (Diovan, Diovan HCT).

• Potassium-sparing diuretics, such as spironolactone (Aldactone).

If you take any of these, ask your doctor to include a potassium test in your annual blood work. For adults, a normal blood potassium level is 3.5 to 5.0 milliequivalents per liter (mE1L) or millimoles per liter (mmol/L).

...you have certain diseases. Medical conditions that impair potassium excretion include diabetes, chronic kidney disease, end-stage renal disease, severe heart failure, and adrenal insufficiency.

Where to Get Your Potassium

From foods. Vegetables and fruits are rich in potassium—especially bananas, potatoes, oranges, avocados, spinach, melon, apricots, beans, and broccoli.. Other good sources are meat, milk products, nuts, and peanut butter.

From supplements. These can help, but only up to a point. You have to swallow a lot of tablets or capsules to get your daily requirement (see the photo above)—and your body may not absorb it all. In addition, the active ingredient is often potassium chloride, which cannot neutralize excess acid in the body and probably won't help you prevent kidney stones or bone loss. If you must take supplements, look for those containing potassium citrate or potassium gluconate.