Potassium
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Potassium is a mineral and an electrolyte. Electrolytes are compounds that are able to conduct an electrical current.

Functions
Potassium's functions:
  • Helps regulate fluids and mineral balance in and out of body cells
  • Helps maintain your normal blood pressure
  • Helps transmit nerve impulses
  • Helps your muscles contract

Recommended Intake
Most people should aim to get close to 5,000 milligrams (mg) of potassium per day.

Age Estimated Minimum Requirement of Potassium (mg) 9-13 years4,500> 13 years4,700
Potassium Deficiency
Severe potassium deficiency leads to a low blood potassium level in the blood, called hypokalemia. But a potassium deficiency is rare in healthy people. However, certain conditions can cause the body to lose significant amounts of potassium. These conditions include the following:
  • Excessive diarrhea, or laxative use
  • Kidney problems
  • Use of certain blood pressure medications:
    • Thiazide diuretics (such as hydrochlorothiazide)
    • Loop diuretics (such as furosemide)
  • Continuous poor food intake which may occur due to the following:

Signs of a severe potassium deficiency include the following:
  • Weakness
  • Appetite loss
  • Nausea
  • Fatigue
  • Confusion
  • Apathy
  • Constipation

If hypokalemia persists, it can lead to irregular heartbeat. This can dangerously decrease the heart's ability to pump blood. People who are on medication for high blood pressure should ask their physician about the need for a potassium supplement.

Potassium Toxicity
Potassium is rarely toxic because excess amounts are usually excreted in the urine. However, people with kidney problems may be unable to properly excrete potassium, allowing it to build up in the bloodstream. A high level of potassium in the bloodstream is called hyperkalemia. Hyperkalemia can cause slowed heartbeats and may eventually cause the heart to stop beating. Therefore, people with kidney problems need to closely monitor their potassium intake.

Major Food Sources
Potassium is found in many foods, especially fruits and vegetables. Less processed foods tend to have more potassium.

Food (amount)Serving Size Potassium Content (mg) Dried figs10 figs1331White beans, canned1 cup1189Avocado, raw, California1 medium1097Potato, baked with skin1 medium844Navy beans, canned1 cup755Raisins, seedless2/3 cup751Lentils, boiled1 cup731Clams, canned and drained3 ounces534Yogurt, low fat, plain1 cup531Lima beans, canned1 cup530Banana1 medium420Orange1 medium233Dried apricots10 halves482Cantaloupe1 cup pieces494Tuna, yellowfin, cooked by dry heat3 ounces484Swiss chard, boiled½ cup483Orange juice, from frozen concentrate8 fluid ounces473Honeydew melon1 cup pieces461Winter squash½ cup cubes446Snapper, cooked by dry heat3 ounces444Cod, Pacific, cooked by dry heat3 ounces440Spinach, boiled½ cup419Sweet potato, baked with skin1 medium397Bell pepper, yellow, raw1 large394Bass, freshwater, cooked by dry heat3 ounces388Milk, fat-free8 fluid ounces380Kidney Beans, cooked½ cup360Pineapple, canned in juice1 cup pieces305Tomato, red, stewed, canned½ cup305
Health Implications
Blood Pressure
Potassium is believed to play an important role in the regulation of blood pressure. According to a review of 33 studies in the Journal of the American Medical Association , increasing potassium intake can produce a slight but definite drop in blood pressure levels. This effect, however, is unlikely to be strong enough to allow a reduction in blood pressure medication.

Tips for Increasing Your Potassium Intake
To help increase your intake of potassium:
  • Eat legumes, such as black beans, lentils, and chickpeas, three times per week. Combine them with rice and vegetables and wrap in a warm tortilla.
  • Make garden salads with half green lettuce and half fresh spinach.
  • Eat fish as your entrée a few times per week.
  • Snack on raisins and other dried fruits for a sweet fix.
  • Use avocado on sandwiches or bagels in place of mayonnaise or cream cheese.
  • Eat two brightly colored fruits and vegetables each day; these include sweet potato, Swiss chard, cantaloupe, honeydew melon, tomato, spinach, and yellow bell pepper, among others.




RESOURCES:
American Dietetic Association

Dietary Guidelines for Americans
United States Department of Agriculture

CANADIAN RESOURCES:
Canadian Council on Food and Nutrition

Dietitians of Canada

References
Duyff RL. The American Dietetic Association's Complete Food & Nutrition Guide . 3rd ed. Hoboken, NJ: John Wiley and Sons, Inc; 2006.

Hypertension. DynaMed website. Available at: http://dynaweb.ebscohost.com/Detail.aspx?id=115345&sid=cdbf687a-f131-4b48-9503-549caa563192@sessionmgr3 . Accessed February 15, 2008.

The Nutrition Desk Reference. Keats Publishing; 1995.

Perspectives in Nutrition . 2nd ed. Mosby Year Book, Inc.; 1993.

Whelton PK, He J, Cutler JA, et al. Effects of oral potassium on blood pressure. Meta-analysis of randomized controlled clinical trials. JAMA . 1997;277:1624–1632.

Last Reviewed Review in Progress