Potassium in diet

Alternative names 
Diet - potassium

Definition
Potassium is a mineral that is involved in both electrical and cellular functions in the body. (In the body it is classified as an electrolyte).

Function

Potassium is a very important mineral to the human body. It has various roles in metabolism and body functions:

     
  • It assists in the regulation of the acid-base balance and water balance in the blood and the body tissues.  
  • It assists in protein synthesis from amino acids and in carbohydrate metabolism.  
  • It is necessary for the building of muscle and for normal body growth.  
  • It is needed for the proper functioning of nerve cells, in the brain and throughout the body.

Food Sources

Fish such as salmon, cod, flounder, and sardines are good sources of potassium. Various other meats also contain potassium.

Vegetables including broccoli, peas, lima beans, tomatoes, potatoes (especially their skins), and leafy green vegetables such as spinach, lettuce, and parsley contain potassium.

Fruits that contain significant sources of potassium are citrus fruits, apples, bananas, and apricots. Dried apricots contain more potassium than fresh apricots.

Side Effects

A deficiency of potassium (hypokalemia) can occur in people with chronic disease or as a result of the aging process. The most common problems associated with reduced potassium levels are hypertension, congestive heart failure, cardiac arrhythmias, depression, and fatigue.

A variety of conditions can cause the loss of potassium from the body. The most common of these conditions are vomiting, diarrhea, and other gastrointestinal problems.

Hypokalemia can also be caused when too much water is taken in too quickly in conjunction with heavy perspiration - for example, in an overzealous attempt to prevent dehydration during sports. This can affect marathon runners and other serious athletes.

Kidney disease (such as acute renal failure) and diabetes, depending on the stage of either, can also cause fluctuations in the levels of potassium. Additionally, many medications can cause depletion of potassium. Examples include diuretics, cortisone, prolonged use of aspirin, and laxatives.

The most common symptom of potassium depletion is fatigue. Other symptoms of potassium deficiency include slow reflexes, muscle weakness, and dry skin. A quick loss of potassium could lead to cardiac arrhythmias.

Severe potassium deficiency symptoms include decreased heart rate, extreme muscle weakness, bone fragility and, if untreated, death. A low level of potassium can be determined with a blood test and can be treated with potassium supplements.

Increased levels of potassium in the blood is known as hyperkalemia. Some common causes of this are reduced renal (kidney) function, an abnormal breakdown of protein, and severe infection. If there is no pathological cause for increased potassium levels, the kidneys are able to handle a large amount of potassium, and prevent the blood levels from increasing.

Recommendations

There is no recommended daily allowance for potassium, although experts recommend approximately 2 to 2.5 grams per day. The average American diet provides 2 to 6 grams of potassium per day.

Over-the-counter potassium supplements provide 99 milligrams of potassium per tablet. Potassium supplementation should never be taken without the approval of a health care provider.

Johns Hopkins patient information

Last revised: December 4, 2012
by Janet G. Derge, M.D.

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