Skip to comments.Preserving a Delicate Balance of Potassium
Posted on 06/27/2004 4:45:54 PM PDT by neverdem
Evolution is an excellent teacher when it comes to figuring out what and how much people should eat.
For example, primates (including those with two legs and big brains) evolved on foods rich in potassium and very low in sodium. Early humans evolved to conserve sodium, which was hard to obtain, and to excrete excess potassium, abundant in many fruits and vegetables.
But Western-style diets these days are the reverse of what those early humans consumed, rich in processed foods, loaded with sodium and relatively poor in potassium. Consequently, according to a report released this year by the National Academy of Sciences Institute of Medicine, many people now consume diets deficient in potassium and high in acid-generating foods like meats and other animal proteins that further deplete the body's supply of this vital mineral.
According to national diet surveys, the average man in this country consumes only about two-thirds the recommended amount of potassium each day, and the average women consumes even less - half of the 4,700 milligrams a day considered to be an adult's adequate daily intake.
As the institute report explained, "Humans evolved from ancestors who habitually consumed large amounts of uncultivated plant foods, which provided substantial amounts of potassium. In this setting, the human kidney developed a highly efficient capacity to excrete excess potassium."
A Crucial Nutrient
Normal healthy kidneys are not effective at conserving potassium and are thus unable to prevent a deficiency when dietary levels of it are low.
Potassium and sodium, along with chloride, are electrolytes. They regulate the electrical potential of cell membranes and, thus, the conduction of nerve impulses. Potassium resides primarily in cells, while sodium and chloride are found mainly outside cells. All three have to be in proper balance to assure normal metabolic and neuromuscular functioning. And the imbalance of high sodium and chloride in relation to potassium is believed to be a major factor in several serious chronic ailments.
The potential consequences of a chronic potassium deficiency are often unrecognized, even by health professionals. The problems include high blood pressure, heart attacks, strokes, kidney stones and a loss of bone minerals that can lead to osteoporosis. Low potassium consumption can also cause a sensitivity to salt, further raising the risk of hypertension. That is a common problem among African-Americans, who have a much higher risk than whites of developing hypertension and its lethal consequences.
These and other effects of insufficient potassium can occur even when blood levels of the mineral appear to be normal. Furthermore, even small changes in potassium levels can harm nerve transmission, muscle contraction and blood-vessel tone. Most people have little or no warning of potassium deficiencies. They may feel tired, weak and irritable, but unable to pinpoint the cause.
To make matters worse, high-protein levels in diets result in acid formation that increases the loss of calcium, the primary bone mineral. Studies have demonstrated an association between higher consumption of fruit and potassium and increased bone mineral density. The more protein in relation to potassium consumed, the greater the risk of bone loss in the hips and spine.
In its report, the institute was especially critical of the currently popular low-carbohydrate high-protein diets. Although these diets may contain enough potassium from protein, they lack enough alkali-generating substances from fruits like oranges, bananas and grapes to counter the high acid formation associated with a protein-rich diet.
In a six-week study of 10 adults on a low-carbohydrate, high-protein diet, calcium loss in urine increased by 50 percent and was not compensated for by an increase in intestinal absorption of dietary calcium.
The researchers concluded that the diet overloaded the kidneys with acid, increased the risk of formation of kidney stones, led to a net loss of calcium and might have increased bone loss. The institute noted that there had been "no published studies of the long-term metabolic effects of this kind of diet in any group of individuals."
People taking certain diuretics - thiazide and loop diuretics -to lower blood pressure or to counter fluid retention may also incur a potassium deficiency, because those drugs increase urinary loss of both sodium and potassium. Such patients are commonly told to take potassium supplements, typically potassium chloride, although chloride has a counterproductive acidic effect.
Also at risk of potassium deficiency, even when consuming an adequate diet, are people who sweat excessively as a result of high heat or extreme exercise. Both situations increase the need for potassium, which is best met through increased consumption of potassium-rich fruits, vegetables and juices.
,strong>Dangers of Excess
Excessive blood levels of potassium can cause fatal disruptions in heart rhythms. And several common health problems can lead to high blood levels of potassium, even when potassium consumption is not above the recommended level.
People at risk include those with chronic kidney disease, heart failure, Type 1 diabetes and adrenal insufficiency, each of which can interfere with the kidneys' ability to excrete potassium. Also, drugs called ACE inhibitors, angiotension receptor blockers and potassium-sparing diuretics, commonly used to treat high blood pressure and congestive heart failure, increase the risk of a harmful excess of potassium in the blood. Also at risk are people suffering dehydration, extensive injuries or a major infection.
The institute suggested that people who have those conditions or who are taking such medications should have their potassium levels monitored and should, perhaps, consume somewhat less potassium than that recommended for healthy adults. Experts say no one should take potassium supplements or potassium salt substitutes without medical advice.
To achieve a healthy balance of potassium and sodium, people should eat ample amounts of fresh fruits and vegetables. When such foods are processed, potassium is commonly lost and sodium substantially increased. Nearly all processed foods are sodium rich and potassium poor.
For example, a three-and-a-half-ounce serving of fresh peas has 380 milligrams of potassium and less than one milligram of sodium. The same serving of canned peas, minus the liquid, has 180 milligrams of potassium and 230 milligrams of sodium.
Among the foods richest in potassium, in descending order by caloric value, are leafy greens like spinach, romaine and cabbage; vine-grown foods like tomatoes, cucumbers, zucchini, winter squash and pumpkin; root vegetables like carrots, radishes, turnips and onions; dried peas and beans, and green beans; fruits like apples, oranges, bananas, apricots and strawberries; and tubers like potatoes and sweet potatoes, as well as milk and yogurt. Lesser amounts are found in meats, nuts, eggs, cereals and cheese.
In physically active people, potassium is important to sustaining good muscle function. But sports drinks, often consumed to restore the nutrients exhausted by vigorous exercise, are close to worthless when it comes to replacing potassium.
An eight-ounce serving of a sports drink contains about 30 milligrams of potassium. You would have to drink 12 servings of a sports drink, 600 calories, to consume the amount of potassium in one 65-calorie banana, or consume 375 calories of the drink to get the potassium in 27 calories of a half-cup of cantaloupe.
If you consumed 100 calories each of spinach, tomatoes, carrots, chickpeas, oranges and potatoes, you would easily take in a day's recommended amount of potassium and only 600 calories. A potassium-rich diet is also great for weight control.
Bananas are good too, no?
Here is my #1 rule for healthy eating, only one processed dish per family dinner. I am no health food nut, but you've got to know that any pre-made or 1/2 pre-made food is filled with salt.
HIGH potassium (more than 225 milligrams per 1/2 c. serving)
These foods would be beneficial to athletes or to others who incur heavy fluid loss. Patients on potassium-restricted diets should avoid them, or eat them sparingly, as advised by their nutritionist.
She finally mentioned cantaloupes and bananas near the end.
And the atomic symbol for potassium is "K".
...Sounds like humans need a combinatin of some alkali metals, some alkaline metals, some non metals. The periodic table, balanced with essential elements are yer best bet...
As in kalium?
Thanks for the link, but when I eyeballed the foods with low and and moderate amounts of potassium I found apple juice in the moderate category and apples in the low category. Maybe it's a typo.
OK. So, now - everyone up the banana tree (an irony of evolution). Those in poor shape who cannot get up the banana tree, are to gather melons and cantaloupes.
High Potassium Foods
Apricots, canned and fresh
Dried fruits - apricots, dates, figs, prunes
Potatoes, white and sweet
Vegetable juice cocktail
Red Kidney Beans
Nuts and Seeds
Breads and Cereals
Milk and Milk Products
Thanks for the link.
Also, you might want to trash your table salt and start buying Real Salt, available in your local health food store or online at www.realsalt.com
It has all the trace minerals (including iodine) and tastes much better than Mortons or table salt. Voted best cooking salt by professional chefs, it is how salt comes from the earth naturally. It's not as "salty" as what we're used to using at the table and is sometimes called one of the "sweet salts."
It will clump like salt used to do in the old days when it was humid, which shows that the sellers of salt are putting something in the salt these days to keep it free flowing. Once you've used it, you'll never go back. It's just that good.
I like the first one on your "Miscellaneous" list!
And, Potassium 40 is a mildly RADIOACTIVE isotope, occuring in Nature.
Potassium is VERY important...and Sodium is overloaded in processed foods!
Thanks for the post/ping.
This sodium/potassium balance is not trival nor is it easily explained or controlled.
I take both a diuretic and an ACE receptor blocker. I do lose potassium and supplement it periodically. I find it easy to tell when my potassium level is low, my resting pulse rate increases too high.
Interestingly my normal pulse my entire life was 80. As I got older, it dropped and my blood pressure went up commensurately. After I started on diretics, my pulse rate gradually increased, presumably as I lost excess?? potassium, not sure but it is my thought. Now as it tends to get near 90, I take some potassium and down it comes.
BTW potassaium chloride is what is commonly referred to as salt substitute, it is also what is used to stop the heart in lethal injections if memory serves.