Potassium

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Potassium is a nutrient (macro-mineral). It is an important mineral element in the human body. Optimal levels of potassium in the blood help to strengthen arteries, may reduce the damage to blood vessels associated with ageing, and are essential for the efficient functioning of the heart. Potassium-rich diets may reduce blood pressure and counteract some of the harmful effects of high sodium intakes. Some nutritionists suggest that the addition of one piece of potassium-rich fruit or vegetable per day may reduce the risk of a fatal stroke by 40 per cent.

Although deficiencies are rare, they may result from severe diarrhoea, sweating, or vomiting. Mild deficiencies can lead to muscular weakness, increased heart rates, and nausea. Severe deficiencies may lead to heart failure unless supplements are given.

Potassium is found in many foods (including apricots, meat, fish, and poultry). Fruit and vegetables are especially valuable sources of potassium because they tend be relatively low in sodium. Bananas are an excellent recovery food for replacing potassium lost in sweat and they are very convenient (the original prewrapped food!). For these reasons, many professional cyclists eat bananas during races.

Potassium toxicity is rare, but excessively high intakes can lead to muscular weakness and heart complaints, and may accompany kidney disease. The daily potassium requirement is about 2-4 grams (UK recommended level for adults is 3.5 g per day).

Quick Facts...

* A diet low in potassium and high in sodium may be one of the factors that leads to high blood pressure.
* Eating equal amounts of sodium and potassium is recommended.
* Athletes involved in hard exercise may require larger quantities of potassium-rich foods.
* Potassium is found in meats, milk, fruits and vegetables.

Role in Health

Many people know that high sodium intake may lead to hypertension. Approximately 10 percent of people with high blood pressure are sensitive to dietary salt (or sodium). A reduction in sodium helps lower blood pressure in all people with hypertension.

Newer evidence suggests that dietary potassium may play a role in decreasing blood pressure. Potassium is involved in nerve function, muscle control and blood pressure. A diet low in potassium and high in sodium may be a factor in high blood pressure. Increasing potassium in the diet may protect against hypertension in people who are sensitive to high levels of sodium.

For people who have hypertension, following an overall eating plan called DASH (Dietary Approaches to Stop Hypertension) may be useful for lowering blood pressure. The DASH diet is higher in potassium, magnesium, and calcium, and lower in total fat, saturated fat, and sodium than the typical American diet. For more information about the DASH eating plan or diet and hypertension in general refer to fact sheet 9.318, Diet and Hypertension.

However, taking potassium supplements is generally not recommended for people with high blood pressure. Instead, a variety of potassium-rich foods should be eaten daily.

Athletes also may need more potassium to replace that lost from muscle during exercise and the smaller amount lost in sweat. Low potassium can cause muscle cramping and cardiovascular irregularities. Eating foods high in potassium can prevent these symptoms. One cup of orange juice, a banana or a potato is sufficient to replace the potassium lost during one to two hours of hard exercise. Sport drinks are poor sources of potassium.

What Does it Do?

Potassium works with sodium to maintain the body's water balance. One possible explanation for potassium's protective effect against hypertension is that increased potassium may increase the amount of sodium excreted from the body.

The kidneys regulate the level of potassium in the body. Potassium deficiency is not common but may result from excessive losses due to severe diarrhea, poor diabetic control, low-calorie diets (less than 800 calories per day), chronic alcoholism, hard exercise, or some diuretics and laxatives.

Although their purpose is to eliminate excess sodium from the body, certain diuretics may increase potassium losses, while others retain potassium. If you take certain diuretics, you may need more or less potassium. Ask your physician about the type of diuretic drug you take and whether you require additional potassium. Some people who take diuretics may be prescribed a potassium supplement to help replace potassium loss.

How Much Potassium?

Most Americans do not get enough potassium in their diets. The recommended daily potassium intake is 4.7 grams a day. Athletes involved in prolonged, hard exercise may require more potassium a day.

Food Sources

Potassium is found in many foods, especially meat, milk, fruits and vegetables (see Table 1). Eat a variety of foods to get the recommended amount.

While sodium is added to most highly processed foods, potassium is not. Eating more fresh and frozen foods, which are usually lower in sodium, may be helpful. (See fact sheet 9.354, Sodium in the Diet.)

Potassium is essential for good nutrition and health. Meeting the minimum requirement is not difficult if you eat a variety of foods. Maintaining the recommended sodium-to-potassium ratio, however, may be more difficult. Eat more fruits and vegetables and fewer processed foods. A moderate increase in dietary potassium, in addition to a reduction of excess sodium, may be beneficial, especially for people at risk for hypertension.

References

* Altschul, Aaron. 1981. Sodium Sensitivity, Processed Foods and Hypertension. Lillian Fountain Smith 1981 Conference for Nutrition Educators Proceedings. pp. 135-141.
* Clark, Nancy. 1990. Sports Nutrition Guidebook: Eating to Fuel Your Active Lifestyle. Leisure Press, Illinois.
* Darling, Mary. 1982. Potassium: Its functions and Sources. Agricultural Extension Service, University of Minnesota, Extension Folder 652.
* National Research Council, 1990. Recommended Dietary Allowances. pp.173-178.
* U.S. Department of Agriculture. Agricultural Research Service. Agricultural Handbook No. 8.
* Institute of Medicine of the National Academies. www.iom.edu.

Table 1: Where's the potassium?
Very good sources (300 mg or more) Fair sources (200-300 mg) Poor sources (less than 100 mg)
Source Serving size Source Serving size Source Serving size
Breads and Cereals
None None Bread 1 slice
Breakfast cereal 1/2 cup
Pasta 3/4 cup
Dairy
*Buttermilk 1 cup Ice cream 1 cup *American cheese 1 ounce
Milk 1 cup Natural cheese 1 ounce
Yogurt 1 cup Eggs 1
Fruit
Apricots 3 Apples 1 large Applesauce 1/2 cup
Avocado 1/4 Grapefruit juice 1/2 cup Blueberries 1/2 cup
Banana 1 medium Orange 1 medium Grapes 10 medium
Cantaloupe 1 cup Orange juice 1/2 cup
Dates 10 medium Peaches 1 medium
Honeydew melon 1 cup Strawberries 1 cup
Nectarines 1 large
Prunes 10 medium
Raisins 1/4 cup
Meat
Chicken 3 ounces Beef 3 ounces *Bacon 3 slices
Fish 3 ounces *Ham 3 ounces *Bologna 1 slice
*Canned salmon, tuna 3 ounces Lamb 3 ounces *Corned beef 3 ounces
Turkey 3 ounces Pork, fresh 3 ounces *Frankfurter 1
Vegetables**
Carrot 1 large Broccoli 1/2 cup Corn 1/2 cup
Celery 1 stalk Beets 1/2 cup *Olives 10
Dry beans, cooked 1/2 cup Peas 1/2 cup
Greens, cooked 1/2 cup
Potato, baked 1 medium
Spinach 1/2 cup
Squash, winter 1/2 cup
Sweet potato 1 large
Tomato 1 large
*Tomato juice 1 cup
Other
Molasses 2 tablespoons *Dill pickle 1 Butter 1 tablespoon
Nuts, unsalted 1/2 cup Peanut butter 2 tablespoons Salad dressing 1 tablespoon
* These foods have a high sodium content (greater than 300 mg per serving).
** Canned vegetables have a much higher sodium content than fresh or frozen vegetables.


Alternative Medicine Encyclopedia: Potassium

Description

Potassium is one of the electrolytes essential to the smooth running of the human body; in fact just about all bodily functions depend on it to some extent. It is also one of the most abundant minerals in the body, constituting 70% of the positive ions inside cells; the rest are a mixture of sodium, magnesium, calcium, arginine, and others. Potassium is distributed to the cells by a process of passive diffusion and is regulated by an enzyme called adenosinetriphosphatase together with the level of sodium concentration inside the cell. Potassium and sodium are antagonistic, which means that an imbalance of one will automatically cause an imbalance of the other; normally potassium should predominate inside the cell.

General Use

Potassium is necessary for normal cell respiration; a deficiency can cause decreased levels of oxygen, which will reduce the efficiency of cell function. Adequate supplies of potassium are also required to regulate heartbeat, facilitate normal muscle contraction, regulate the transfer of nutrients to cells, and regulate kidney function and stomach juice secretion, among other things. One of the most important uses of potassium in the body is in the process of nerve transmission, as it is a cofactor catalyst for the activation of several enzyme systems, but since only minute amounts are required for these processes, deficiency in this respect is unlikely.

Potassium is thought to be therapeutically useful in many ways, including assisting in the treatment of alcoholism, acne, alleviating allergies, promoting the healing of burns, and preventing high blood pressure. It can also help with such problems as congestive heart failure, chronic fatigue syndrome, or kidney stones. People suffering from any of the above should consider increasing their intake of potassium after talking to a professional.

Symptoms of Potassium Deficiency

A deficiency of potassium in the blood is referred to as hypokalemia and manifests itself in many ways. Among the most serious are arthritis, high blood pressure, heart disease, stroke, cancer, and even infertility, as potassium constitutes a vital element of seminal fluid.

Potassium deficiency will increase acid levels in the body, lowering the natural pH, which will have far reaching effects. Lack of potassium can also aggravate problems caused by lack of protein. If potassium levels are down, the liver cannot operate normally, particularly regarding transformation of glucose to glycogen. A healthy liver should have about twice as much potassium as sodium.

Potassium deficiency can cause problems with the formation of connective tissue, and can render normally strong body tissue vulnerable to all kinds of problems. The collagen of a healthy person is approximately as strong as steel, and the strength of bone tissue can be likened to that of cast iron. Lack of potassium may create a susceptibility to fractures, skin lesions that do not heal, or other connective tissue problems. So important is potassium for the protection of collagen that many natural health gurus claim that along with other vital nutrients, it constitutes an essential element of protection against premature aging. As long ago as the 1920s, Max Gerson was the first person ever to cure lupus lesions with a diet designed to reduce abnormally high sodium levels and raise potassium levels to normal, which was entirely raw fruit and vegetables.

Potassium is essential to the efficient processing of foods in the body; without it they cannot be broken down into the proper compounds. This can lead to rheumatism, and is one reason why adequate potassium prevents rheumatism.

Potassium Requirements

In the past potassium was more plentiful in the diet than salt, but gradually, the situation has been reversed. The widespread lack of potassium in modern diets is largely due to modern processing and high levels of salt added to most processed foods. Cooking and processing destroy potassium, and added salt further robs the body of vital potassium. This departure from traditional cooking of fresh homegrown fruit and vegetables is likely the cause of many health problems faced by modern society.

Who Needs Potassium Supplements?

Those who may need to take potassium supplements include women who take oral contraceptives, abusers of alcohol or drugs, smokers, athletes, workers whose job involves physical exertion, patients who have had their gastrointestinal tract surgically removed, anyone suffering from any degree of malabsorption syndrome, and vegetarians. People who have eating disorders, especially bulimia and anorexia, are particularly at risk from damage due to low potassium levels. Also, individuals who have been ill, anyone who has undergone surgery and those who are taking cortisone or digitalis preparations, and those suffering from high levels of stress will probably also have low potassium levels.

No RDA has been officially established for potassium, but practitioners recommend that the optimal daily intake should be in the region of 3,500 mg. The average daily intake is about 2,500 mg. However, in general, nutritionists recommend reducing salt intake and ensuring adequate supply by increasing the amount of fresh fruit and vegetables in the diet.

If a person feels that he or she may be suffering from a potassium deficiency, but would like to make sure before taking supplements, there are a variety of laboratory tests that can be conducted. They include serum-potassium determinations (although these may be unreliable unless levels are very low), serum creatinine, electrocardiograms, serum-pH determinations, whole blood, sublingual cell smears, and red blood cell potassium level determinations.

Preparations

Absolutely the best sources of potassium are fresh natural foods. Supplements may have side effects and large doses must be taken to approach the levels of potassium that can be obtained from food; the average tablet contains about 90 mg, for example, and a medium banana contains 500 mg. Vegetables containing the highest levels of potassium are generally those containing the lowest levels of starch. Seaweed has an amazingly high potassium content, containing roughly ten times as much as leafy vegetables, but also contains a large amount of mineral salt. Green coconut milk is another source of potassium.

Plentiful Sources of Potassium

There is a great variety of natural foods that are an excellent source of potassium. These include avocados; bananas; chard; citrus fruits; juices such as grapefruit, tomato, and orange; dried lentils; green leafy vegetables; milk; molasses; nuts such as almonds, brazils, cashews, peanuts, pecans and walnuts; parsnips; dried peaches; potatoes; raisins; sardines; spinach; and whole-grain cereals.

Cooking

Boiling food in water is a sure way to lose the potassium in it, unless it is to make soup. Baking and broiling are ways in which food can be cooked while at the same time preserving the potassium content, indeed, these methods preserve all the nutrients apart from vitamin C and some of the B vitamins which are destroyed by heat. Broiling also oxidizes essential fatty acids. Stir-frying is also a good way of preserving nutrients. It is important to vary the intake of potassium rich foods in order to ensure adequate intake of other nutrients and to avoid the possibility of toxicity, as some vegetables contain elements that are toxic if they are eaten in large amounts (oxalic acid in rhubarb for example). It is important to note that freezing also depletes potassium levels in foods.

RECIPE FOR POTASSIUM BROTH. Many variations are to be found under the heading "potassium broth," and most natural health practitioners recommend one version or another, but the main constituents are the following vegetables, generally any vegetable of choice can be added to this base.

Ingredients

* 2 lb potatoes
* 1 lb carrots
* 1/2 lb peas
* bones for stock, or a vegetable bouillon cube
* 4 oz cracked wheat or pearl barley

First, in a stainless steel pan, boil the stock bones, if using them. After about one hour, add the remaining ingredients and continue to simmer in plenty of water for about another hour. It is preferable to use the potatoes and carrots well scrubbed, but with their skins on, as this retains valuable nutrients. Keep any unused soup in the refrigerator.

Potassium Supplements

Potassium supplements come in either tablet or liquid form, and anything over 390 mg needs a prescription in the United States. Enteric coated tablets have been known to cause ulcers, as they do not dissolve until they reach the intestines and may prove too concentrated for the undefended intestinal wall. To be on the safe side, supplements should be taken with a glass of juice. Slow-release enteric-coated supplements are now available, which decrease the danger of ulcers. Potassium gluconate is the ideal supplement, as it more closely resembles the potassium found in plants. Small divided doses should be taken, as opposed to one large dose, when treating a potassium deficiency. Athletic drinks are an electrolyte replacement and as such contain potassium. Potassium supplements should be kept in a cool, dry place, out of direct light. They should not be frozen and should not be kept in the bathroom medicine cabinet as heat and moisture may reduce effectiveness.

Precautions

In general, the multitude of nutrients that humans require in order to stay healthy are synergistic, which means they are interdependent. If depleted of one, it is highly likely that there are deficiencies in others. Many nutrients, for example, require the presence of either calcium or vitamin C for efficient use by the body, and if suffering from a deficiency of any of the B vitamins, there is almost certainly a deficiency in the B vitamins in general, as they occur together in nature. With this in mind, it is very unwise to take large amounts of any one nutrient without making sure that the full spectrum of nutrients is plentifully available for the body to make use of. This can best be achieved by making sure that a large proportion of the daily diet is in the form of raw fruit and vegetables, whole grains, and unroasted nuts.

Of all the essential nutrients that are commonly taken as supplements, potassium is perhaps the most dangerous. Only 14 grams of potassium can cause death under certain circumstances, particularly when intake is low at other times, as it has been found that when potassium intake is restricted, somehow the mechanism for utilizing it is altered, so that large amounts cannot be processed.

Just the right amount of potassium is essential. Too much or too little can cause muscle spasms and cramps if a calcium deficiency also exists. With this in mind, it is important to ensure adequate intake of calcium and vitamin D, which will promote the uptake of calcium in the body.

Many sufferers of degenerative diseases such as tuberculosis, cancer, and arthritis, suffer from high serum potassium levels. This is not because they have too much serum, but because the disease affects body functions in such a way that it throws off this valuable nutrient instead of using it. In such cases, natural sources of potassium, such as fresh fruit or vegetable juice, can be more effective than supplements.

Potassium and Heart Disease

Potassium has been implicated in the treatment of heart disease since the 1930s, but some heart disease that is due to malnutrition does not respond to potassium. Indeed, because of the impaired ability of the body to take up potassium, it can be dangerous. Most heart disease patients of the Western world, however, can benefit from an increase in potassium levels.

Potassium and Arthritis

For many, when they begin to eat a well balanced selection of fresh vegetables and fruits, and eliminate a large proportion of processed, denatured foods, they begin to feel amazingly well very quickly, as the potassium/sodium balance in the body is restored. Tiredness and other symptoms, such as arthritis, are soon replaced with renewed energy and vigor, and the body is able to replenish itself and finds new strength. However, potassium is only partially successful at treating osteoarthritis.

Side Effects

Those who are taking potassium-sparing diuretics, such as spironolactone, triamterene, or amiloride should not take potassium supplements. Anyone allergic to potassium supplements or those who have kidney disease should not take them either. Those suffering from Addison's disease, heart disease, intestinal blockage, stomach ulcers, those using medication for heart disease, or taking diuretics, or who are above the age of 55, should consult a doctor before taking potassium supplements. There are no contradictions for pregnant or breast feeding women, although they should not take mega-doses.

ECG and kidney function tests can be affected by potassium supplementation, the doctor should be informed if potassium supplements are being taken. However, supplementation will not affect blood tests, unless they are to measure serum-potassium levels.

Symptoms of Potassium Overdose

Overdose symptoms of potassium include listlessness, mental confusion, tingling of limbs, weakness, pallid complexion, low blood pressure, and an irregular or fast heartbeat. These symptoms can progress to a drop in blood pressure, convulsion, coma, and eventually cardiac arrest, and can also be triggered by any kind of shock to the system. If any of the above symptoms occur, or in cases of bloody stool (may appear black and tarry), or difficulty in breathing or nausea, medical help should be sought immediately. High serum-potassium is the major problem with shock and is the major cause of death in cases of shock or injury. This is a life-threatening situation, and self treatment is not appropriate.

If such an emergency occurs and medical help is not available, a glass of water containing half a teaspoon of salt, a quarter of a teaspoon of bicarbonate soda and a little honey will help. Potassium supplements should be taken with extreme care in cases of dehydration, as this can be fatal. Adequate liquids, particularly juice, should always accompany the supplement.

Interactions

Care should be taken when taking potassium supplements in conjunction with diuretics. A practitioner should be consulted. A doctor should be informed when a patient is taking potassium supplements. In addition, the following are known to react with potassium:

* Amilorid: causes a dangerous rise in blood potassium.
* Atropine: increases the possibility of intestinal ulcers, which may be caused by potassium supplements.
* Belladonna: increases possibility of intestinal ulcers.
* Calcium: increases likelihood of heartbeat irregularities.
* Captopril: increases likelihood of potassium overdose.
* Digitalis preparations: may cause irregular heartbeat.
* Enalapril: increases chance of overdose.
* Laxatives: may decrease effectiveness of potassium (due to the fact that they leach potassium from the body).
* Spironolactone: increases blood potassium.
* Triamterene: increases blood potassium.
* Vitamin B12: slow release supplements may decrease the absorption of vitamin B12, increasing requirements.

Resources

Books

Gerson, Max. A Cancer Therapy. California, Totality books: 1977.

Other

Weber, Charles. "Roles of Potassium in the Body." http://www.members.tripod.com/~charles_W/arthritis4.html.

[Article by: Patricia Skinner]

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