Potassium

Why potassium is good for you

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.

Potassium is required to to enable all the muscles in the body (both skeletal and smooth muscles) to contract efficiently. Many muscles have special channels so that potassium can move either freely or with the assistance of a special pump, in and out of cells to help with the muscle contraction.

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. Anyone with a heart condition might also retain too much water because the heart is not pumping very well

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, as well as the other electrolytes (chloride and sodium), but especially potassium are needed to help regulate the extra fluid that pregnant women experience during pregnancy

Important potassium facts

Potassium:

• is important in maintaining electrolyte and fluid balance
• is important for maintaining cell integrity
• helps to convert glucose into glycogen so it can be stored in the liver and muscles, which will be later released when required.
• works together with sodium and chloride 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.
• is required to enable nerve impulse to relay signals with rapid transmission throughout the body
• primary role is inside the cells of the body, where it helps to control the amount of fluid in the cells and enzyme reactions in the cells
• helps the cells absorb various nutrients through the cell membrane
• enables toxins and waste products to be removed from the cells
• helps to remove excess fluid from inside the cells

Potassium works best with

• Vitamin B6 (pyridoxine)
• Vitamin D
• Calcium
• Chloride
• Magnesium
• Phosphorus
• Zinc
• Insulin

Potassium and health

• 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
• Regular heartbeat – potassium is especially important in ensuring that the heartbeat is regular, through the function that potassium has on muscle contraction by having a beneficial effect on electrical activity in the heart so that it is healthy and the heartbeat is normal
• 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
• Regulates acidity in the body – potassium’s role in regulating the extracellular fluid (the fluid outside the cells and between them), it is also required to help regulate the pH level (acidity) of all body fluids so that they remain at an appropriate and healthy level

People who wish to take a potassium supplement should talk to a medical professional before taking it.

Groups at risk of potassium deficiency

In general, deficiency in any of the electrolytes, including potassium does not normally occur as not much is required to meet RDI and most people get enough potassium from their foods.

The only people who may be at a risk for a potassium deficiency are:

• 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 smoke cigarettes – smoking tobacco cigarettes can cause a potassium deficiency (as well as deficiency in many other vitamins and minerals) and supplementation may be needed

People who wish to take a potassium supplement should talk to a medical professional before taking it.

In general, deficiency in any of the electrolytes, including potassium does not normally occur

Symptoms of potassium deficiency

• 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

People who experience any of the symptoms above should seek the advice of their doctor about potassium supplementation

Potassium in food

Potassium recommended daily intake (RDI)

The tolerable upper limits should only be taken for short periods and only under medical supervision.

Toxicity levels of 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 potassium toxicity

Acute toxicity of potassium from taking too much in potassium supplements – over 12,000mg (12g) – can cause the following symptoms:

• arrhythmia (irregular heartbeat)
• Bloody or black stools (poo)
• Confusion *
• Convulsions *
• Diarrhoea
• Difficulty breathing *
• Fever
• Kidney death
• Vomiting
• Weakness

* People who experience the highlighted symptoms should seek immediate emergency treatment.

Chronic potassium toxicity

Chronic toxicity of potassium from taking higher than the therapeutic dose of potassium supplements (more than 5,000mg) for a long time can cause the following symptoms:

• Confusion
• Elevated potassium levels
• Heart attack
• Kidney failure
• Lethargy and fatigue
• Nausea
• Paralysis, numbness or heaviness of legs or arms
• Tingling in hands or feet

People experiencing any of the above toxicity symptoms should discontinue their potassium supplements and seek medical advice. Overdosage and toxicity is more likely to occur from taking too many supplements, whereas dietary intake of potassium is highly unlikely to cause overdosage.

Precautions

Certain people should not take potassium supplements as they could cause severe and toxic effects:

• People with kidney or liver disease
• People taking potassium-sparing diuretics
• People with hyperkalaemia (high potassium blood levels)

Other people should seek medical advice before taking potassium supplements:

• People with Addison’s disease
• People with heart disease
• People taking heart medications
• People with diabetes
• People taking heart medication
• People taking diuretics
• People with gastrointestinal disorders
• People with chronic diarrhoea or taking laxatives for diarrhoea
• People using low-sodium salt substitutes

Potassium interactions with medications and supplements

The following are the medications and supplements that are more likely to cause a reaction with potassium supplements:

• ACE inhibitors (Captopril, Enalapril, Llisinopril
  ACE inhibitors such as captopril, enalapril, and lisinopril (used for people with high blood pressure and heart failure) taken together with potassium supplements, can elevate blood potassium levels.
• Amiloride
  Amiloride, a medication used for reducing blood pressure and fluid retention can cause potassium levels to be highly elevated so taking potassium supplements with this medication is not advised, as it can result in a condition called hyperkalaemia (high blood potassium levels), which has serious and adverse health implications.
• Atropine or Belladonna
  If potassium supplements are taken at the same time as Atropine (which is derived from Belladonna), a medication use to control diarrhoea, could cause an exacerbation of the side effects of this medication, which are: gastrointestinal problems, including ulcers and vomiting.
• Beta-blockers (Metoprolol and Propranolol)
  Beta-blockers such as metoprolol and propranolol (used to treat people with high blood pressure and arrhythmias) taken at the same time as potassium supplements can decrease the uptake of potassium from the blood into the cells, causing an excess of potassium in the blood, which is a potentially dangerous condition – hyperkalaemia
• Calcium
  If potassium supplements are taken at the same time as calcium supplements, the combination can increase the risk of having irregular heartbeat.
• Cortisone
  Cortisone (use to treat inflammatory disorders such as arthritis) can cause low blood levels of potassium as a side effect and if taken with potassium, may inactivate the potassium and decrease the effect of the supplement.
• Cyclosporine
  Cyclosporine (used after organ transplant to prevent rejection of the new organ) can cause high blood potassium levels (Hyperkalaemia) as a side effect, so if it is taken at the same time as potassium supplements may cause dangerously high blood levels of potassium. Potassium supplements should not be taken with Cyclosporine.
• Digitalis preparations
  Digitalis preparations (used to treat heart disease) can cause interfere with potassium absorption by either increasing or decreasing it and if this medications is taken with potassium supplements, can cause an irregular heartbeat (arrhythmia). Potassium supplements should not be taken with digitalis preparations.
• Diuretics
  Diuretics such as Spironolactone, Tramterene, Thiazide and Loop diuretics (used to lower blood pressure and for heart failure) can cause low blood levels of potassium as a side effect and if taken with potassium, may inactivate the potassium and decrease the effect of the supplement.
• Heparin
  Heparin (used to break up blood clots in arteries) may increase risk of elevation of potassium levels (hyperkalaemia) when taken with a potassium supplement.
• Laxatives
  Laxatives (used to empty the bowels) may increase elimination of potassium and cause lowered blood potassium levels.
• Nonsteroidal anti-inflammatory drugs (NSAIDs)
  Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (used to relieve inflammation and pain) may cause an elevated risk of blood potassium levels (hyperkalaemia). Potassium supplements should not be taken with NSAIDs.
• Theophylline
  Theophylline (used to treat COPD and asthma) may increase elimination of potassium and cause lowered blood potassium levels.
• Tramterene
  Triamterene is a potassium-sparing diuretic (water pill) that prevents your body from absorbing too much salt, if taken at the same time as potassium supplements may cause an elevated risk of blood potassium levels (hyperkalaemia). Potassium supplements should not be taken with Tramterene
• Trimethoprim
  Trimethoprim (an antibiotic used for bacterial infections), if taken at the same time as potassium supplements may cause an elevated risk of blood potassium levels (hyperkalaemia). Potassium supplements should not be taken with Trimethoprim.
• Vitamin B12
  Vitamin B12 (cobalamin), if taken together with potassium supplements, especially if the vitamin B12 (cobalamin) supplements are extended-release tablets, can reduce absorption of vitamin B12 (cobalamin).

Other interactions with selenium

There are none reported.

Selenium’s effect on lab tests

There are none reported.

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)

Last updated: 6 May 2024