Potassium
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Potassium

Potassium is a mineral and an electrolyte. Electrolytes are compounds that are able to conduct an electrical current. In addition to potassium they include sodium and chloride.

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. Adequate Intake (AI) levels for potassium have been established for people aged 9 and older.

Age Estimated minimum requirement of potassium
(mg)
9-13 years4,500
> 13 yearss4,700
Pregnancy4,500
Breast-feeding women 5,100

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 vomiting, 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:
    • Alcoholism
    • Anorexia nervosa or bulimia
    • Very low calorie diets

Signs of a severe potassium deficiency include the following:

  • Weakness
  • Appetite loss
  • Nausea
  • Fatigue
  • Muscle cramps
  • 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 figs1331
White beans, canned1 cup1189
Avocado, raw, California1 medium1097
Potato, baked with skin1 medium844
Navy beans, canned1 cup755
Raisins, seedless2/3 cup751
Lentils, boiled1 cup731
Clams, canned and drained3 oz534
Yogurt, low fat, plain1 cup531
Lima beans, canned1 cup530
Banana1 medium420
Orange1 medium233
Dried apricots10 halves482
Cantaloupe1 cup pieces494
Tuna, yellowfin, cooked by dry heat3 oz484
Swiss chard, boiled½ cup483
Orange juice, from frozen concentrate8 fluid oz473
Honeydew melon1 cup pieces461
Winter squash½ cup cubes446
Snapper, cooked by dry heat3 oz444
Cod, Pacific, cooked by dry heat3 oz440
Spinach, boiled½ cup419
Sweet potato, baked with skin1 medium397
Bell pepper, yellow, raw1 large394
Bass, freshwater, cooked by dry heat3 oz388
Milk, fat-free8 fluid oz380
Kidney Beans, cooked½ cup360
Pineapple, canned in juice1 cup pieces305
Tomato, 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
http://www.eatright.org

USDA— Dietary Guidelines for Americans
http://www.health.gov/dietaryguidelines/

CANADIAN RESOURCES:

Canadian Council on Food and Nutrition
www.ccfn.ca

Dietitians of Canada
http://www.dietitians.ca/

References

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

The Nutrition Desk Reference. Keats Publishing; 1995.

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

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

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 February 2008 by Maria Adams, MS, MPH, RD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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