Potassium is one of the major minerals used in the body. It is used to regulate sodium, calcium, as well as a host of other nutrients. Total body potassium is in constant turnover, as it is excreted quite rapidly in the urine.
Although bananas have a popular reputation as a high-potassium food, potatoes contain twice as much potassium as bananas and some other vegetables even more. What the banana does have is the highest potassium-to-sodium ratio – 440:1.
All vegetables are sources of potassium; foods and herbs that are especially rich sources include green leafy vegetables, celery, lettuce, turnips, dandelion, mint leaves, cabbage, potatoes, cucumbers, cauliflower, whole grains (oats, rye), oranges, dates, grapes, raisins, figs, apricots, peaches, sunflower seeds, nuts, dried fruits, bananas.
Processing and cooking leaches potassium out of foods. The human digestive tract is well-suited to processing high-potassium raw foods.
Supplement sources include potassium salts (chloride, bicarbonate), chelates (aspartate, citrate, etc.) or food extracts.
Commercial potassium supplements in the U.S. are limited by the FDA to 99mg which happens to be the recommended daily allowance. A prescription is required for higher doses, even though an average banana may contain 500mg and popular "salt substitutes" made from potassium chloride provide 3,180mg of potassium per teaspoon!
Potassium intake has been associated with lowering blood pressure and there are a variety of mechanisms to explain this possible interaction. Studies have shown that higher potassium diet populations are correlated with lower blood pressure.
When doctors prescribe potassium supplements, it is usually in the range of 1,500 to 3,000mg per day. When given in high-dose pill form, potassium salts can cause nausea, vomiting, diarrhea and ulcers... the following alternative may be more pleasant:
Potassium (potato peeling) Broth
Potassium improves energy levels generally and especially if you have been sick. If you have lost fluids from nausea or diarrhea, potassium broth is an especially good idea. Potassium broth takes advantage of the fact that the outside of a potato is one of the highest plant sources of potassium. Most people think that bananas have the most potassium. Actually bananas have the highest ratio of potassium to sodium.
Choose several appealing potatoes and use a knife to remove the outside 1/4-1/2 inch, including the skin. This is the part most people throw away! If you want to add some other optional vegetables, by all means do so. You might have fun with carrot (with the skin, of course), celery (stalk and leaves), beet greens, fresh parsley, onion, garlic and any other organically grown green vegetables on hand.
Wash and chop all vegetables into small pieces, then add them to water and simmer for 30-40 minutes in a covered pot. The minerals will leach out of the vegetables and into the water. Strain out the vegetables, cool and drink the water (broth). If you have extra broth, you can store it in glass containers in the refrigerator for up to 2 days.
Individuals taking certain prescription drugs including digitalis, potassium-sparing diuretics, and some blood pressure drugs (antiotensin-converting enzyme inhibitors) should consult their doctors before using potassium supplements.
Potassium deficiency is associated with a slow, irregular heartbeat. When taking drugs that might deplete intracellular potassium, one should supplement with oral potassium. Low potassium may cause muscle cramps or worsen an arrhythmia. Since over-the-counter potassium supplements are limited to 99mg each (about 1/5 that in an average banana), dietary or prescription potassium may be necessary.
Potassium and magnesium may be valuable in preventing tachyarrhythmias in Wolff-Parkinson-White Syndrome.
The blood pressure lowering effect of supplemental potassium may be greater in patients receiving a high-salt diet. The amount of dietary potassium required to achieve this effect is, however, not easily obtained.
When potassium is removed from a healthy person's diet, blood pressure often goes up. If a person already has hypertension, low potassium will raise their blood pressure even further. This is the inverse of excess sodium. Potassium and sodium are needed in balance. Eating too much salt upsets this balance and also contributes to high blood pressure. Interestingly, reducing sodium does not lower blood pressure unless potassium is also increased.
In experiments, potassium-supplemented individuals not only had their high blood pressure reduced but reduced their cholesterol measurements as well, confirming that a deficiency of potassium is associated with hypercholesterolemia.
Moderate potassium supplementation improves calcium balance in post-menopausal women. [Sebastian A, Harris ST, et al., Improved mineral balance and skeletal metabolism in post-menopausal women treated with potassium bicarbonate. N Engl J Med 330: pp.1776-81, 1994]