| Potassium | |||||
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- Why potassium is good for you
- Important potassium facts
- Groups at risk of potassium deficiency
- Symptoms of potassium deficiency
- Potassium and health
- Potassium in foods
- Potassium recommended daily intake (RDI)
- Potassium works best with
- Overdosage, toxicity and cautions for potassium
Potassium, along with sodium and chloride, is an electrolyte. An electrolyte is a mineral that dissolves in water and carries an electrical charge. Since the body is mostly made up of water, electrolytes are found everywhere in the body – inside the cells, in the spaces between cells, in the blood, in lymph glands and everywhere else. Potassium has a positive charge (as does sodium, while chloride has a negative charge). Because electrolytes have electrical charges, they can move easily back and forth through cell membranes. This is important because as they move into a cell, they carry other nutrients in with them and as they move out of it, they carry out waste products and excess water.
To keep body fluid levels in balance, cells need to have a lot of potassium inside them and a lot of sodium in the fluids outside them. To keep the balance, sodium and potassium constantly move back and forth through the cell membranes.
Controlling potassium distribution in the cells is a very high priority for the body because if it is in deficit, it can negatively affect the heart and heartbeart.
All three electrolytes – potassium, sodium and chloride – keep the amount of water in the body in balance, carry impulses along the nerves, help make muscles contract and relax and keep the body from becoming too acidic or alkaline. Electrolytes are also required to carry glucose (blood sugar) and other nutrients into the cells and to carry waste products and extra water out again. Electrolytes also regulate blood pressure and heartbeat.
- Potassium is important in maintaining electrolyte and fluid balance
- Potassium is important for maintaining cell integrity
- Potassium, sodium and chloride work together to keep the amount of water in the cells and around them (ie blood) at the right levels. Sometimes the fluid balance gets a little out of whack – extra hormones might make cause water retention; this often happens to women before and during their periods.
- Anyone with a heart condition might also retain too much water because the heart is not pumping very well
- Potassium's primary role is inside the cells of the body
Groups at risk of potassium deficiency
- People that have been vomiting or have severe diarrhoea – will be eliminating most of the chloride in the body and will need to restore the electrolyte balance. A medical professional will usually prescribe an over-the-counter electrolyte remedy for to take. Fluid loss must be replaced by drinking a lot of water. It is vital for small children and babies to replace the water and electrolytes lost from vomiting and diarrhoea, as it can be a serious problem if they are not
People who wish to take a potassium supplement should talk to a medical professional BEFORE taking it.
Symptoms of potassium deficiency
Deficiency in electrolytes does not normally occur as not much is required to meet RDA and everyone gets plenty from their foods.
The one exception is getting severe diarrhoea or vomiting. In that case, electrolytes are quickly lost(especially potassium) with the fluid. Unless the fluids and electrolytes are replaced quickly, this can be serious, especially in small children.
Signs of potassium deficiency are:
- muscle cramps in the legs (this sometimes happens to athletes who sweat a lot in really hot weather)
- nausea
- weakness and lethargy
- confusion
- in severe cases, the heart could fail, but this happens only in a small percentage of cases, if the fluids are not quickly replaced or if there is an underlying heart condition
- High blood pressure - studies show that people who eat a low potassium, high sodium diet are more likely to have high blood pressure. Studies also show that if a person already has high blood pressure, eating less sodium can help bring it down. Studies also show that eating potassium-rich fruits and vegetables reduce high blood pressure and its complications, such as stroke. Uncontrolled high blood pressure can lead to heart disease, kidney disease and stroke
- Stroke prevention - even for people who do not have high blood pressure, potassium could help protect against having a stroke. If potassium intake is low, the odds of having a stroke go up, no matter what other risk factors exist in an individual. According to one long-term study of older adults, just one daily serving of a potassium-rich food could cut the risk of a stroke by 40%! That equals just one banana, glass of orange juice or baked potato a day. And if more than one serving is eaten in one day, the odds against having a stroke may improve even more
People who wish to take an potassium supplement should talk to a medical professional BEFORE taking it.
| FOOD | AMOUNT | potassium (mg) |
|---|---|---|
Potato, baked with skin |
1 medium | 844 |
Black beans |
1 cup | 801 |
Lentils |
1 cup | 731 |
Kidney beans |
1 cup | 713 |
Prune juice |
1 cup | 706 |
Tomato juice |
1 cup | 658 |
Avocado |
½ medium | 550 |
Cantaloupe |
1 cup | 494 |
Chickpeas |
1 cup | 477 |
Orange juice |
1 cup | 474 |
Banana |
1 medium | 451 |
Spinach, cooked |
½ cup | 419 |
Sweet potato |
1 medium | 397 |
Milk |
1 cup | 381 |
Flounder |
230g | 292 |
Tomato |
1 medium | 273 |
Wheat germ |
¼ cup | 259 |
Okra |
½ cup | 257 |
Kiwi fruit |
1 medium | 252 |
Orange |
1 medium | 250 |
Strawberries |
1 cup | 247 |
Carrot, raw |
1 medium | 233 |
Broccoli, cooked |
½ cup | 228 |
Beef mince |
85g | 205 |
Corn |
½ cup | 204 |
Cauliflower, cooked |
½ cup | 200 |
Chicken |
85g | 195 |
Watermelon |
1 cup | 186 |
Potassium recommended daily intake (RDI)
| RDA | lifestage | age | amount |
|---|---|---|---|
| INFANTS | 0-6mths 7-12mths |
500mg 700mg |
|
| CHILDREN | 1-3yrs 4-8yrs |
1400mg 1600mg |
|
| CHILDREN | 9-18yrs | 2000mg | |
| ADULTS | 19-50yrs | 2000mg | |
| SENIORS | 51+yrs |
2000mg | |
| PREGNANT | 2000mg | ||
| LACTATING | 2000mg | ||
| TOLERABLE UPPER LIMIT | none established | ||
| Toxic Levels | >10000mg (or >10g) | ||
The tolerable upper limits should only be taken for short periods and only under medical supervision.
Overdosage, toxicity and cautions for potassium
Potassium toxicity does not occur through nutritional intake of foods high in potassium - it only happens when supplements high in potassium are taken or through certain diseases or treatments.
Acute (>12gm) toxicity - irregular heartbeat, diarrhoea, fever, kidney death, convulsions.
Chronic toxicity - paralysis of the extremities, mental confusion, tingling, weakness, heart attack, kidney failure, dehydration, adrenal insufficiency, elevated blood potassium levels.
CAUTIONS
- People taking certain medications - should discuss potassium supplementation BEFORE taking it, as it could interfere with medication by increasing or decrease its effects and this could be dangerous
- People with hyperkalaemia - should NOT take potassium supplements as they already have higher than normal levels of potassium
references
- Hermansen K. Diet, blood pressure and hypertension. Br J Nutr. 2000:83(Suppl 1):S113-119
- Krauss RM, Eckel RH, Howard B, et al. AHA dietary guidelines. Revision 2000: A statement for healthcare professionals from the Nutrition Committee of the American Heart Association. Circulation. 2000;102:2284-2299
- Osiecki, H. The Nutrient Bible. Bio-Concepts Publishing QLD, 2002
- Perazella MA. Trimethoprim-induced hyperkalemia: clinical data, mechanism, prevention and management. Drug Saf. 2000;22(3):227-236
- Ray K, Dorman S, Watson R. Severe hyperkalemia due to the concomitant use of salt substitutes and ACE inhibitors in hypertension: a potentially life threatening interaction. J Hum Hypertens. 1999;13(10):717-720
- Whitney EN, Cataldo DB, Rolfes SR. Understanding Normal and Clinical Nutrition, 6th Edition. Wadsworth/Thomson Learning, 2002
- USDA National Nutrient Database - provides nutrient values for foods (accessed 5 January 2005)
