potassium

What can high-potassium foods do for you?

• Help your muscles and nerves function properly
• Maintain the proper electrolyte and acid-base balance in your body
• Help lower your risk of high blood pressure

What events can indicate a need for more high-potassium foods?

• Muscle weakness
• Confusion
• Irritability
• Fatigue
• Heart problems
• Chronic diarrhea
• Regular, intense exercise
• Use of certain diuretics

Potassium is found abundantly in many foods, and is especially easy to obtain in fruits and vegetables. Excellent sources of potassium include chard, crimini mushrooms, and spinach.

For serving size for specific foods, see Nutrient Rating Chart below at the bottom of this page.

Description Function Deficiency Symptoms Toxicity Symptoms Cooking, storage and processing Factors that affect function

Drug-nutrient interaction Nutrient interaction Health conditions Supplements Food Sources Public Recommendations References

Description

What is potassium?

Potassium, sodium and chloride comprise the electrolyte family of minerals. Called electrolytes because they conduct electricity when dissolved in water, these minerals work together closely. About 95% of the potassium in the body is stored within cells, while sodium and chloride are predominantly located outside the cell.

Potassium is especially important in regulating the activity of muscles and nerves. The frequency and degree to which our muscles contract, and the degree to which our nerves become excitable, both depend heavily on the presence of potassium in the right amount.

How it Functions

What is the function of potassium?

Muscle contraction and nerve transmission

Potassium plays an important role in muscle contraction and nerve transmission. Many of our muscle and nerve cells have specialized channels for moving potassium in and out of the cell. Sometimes potassium moves freely in and out, and sometimes a special energy-driven pump is required. When the movement of potassium is blocked, or when potassium is deficient in the diet, activity of both muscles and nerves can become compromised.

Other roles for potassium

Potassium is involved in the storage of carbohydrates for use by muscles as fuel. It is also important in maintaining the body's proper electrolyte and acid-base (pH) balance. Potassium may also counteract the increased urinary calcium loss caused by the high-salt diets typical of most Americans, thus helping to prevent bones from thinning out at a fast rate.

Deficiency Symptoms

What are deficiency symptoms for potassium?

Potassium occurs naturally in a wide variety of foods. As a result, dietary deficiency of potassium is uncommon. However, if you experience excessive fluid loss, through vomiting, diarrhea or sweating, or if you take certain medications (see section on Drug-Nutrient Interactions below), you may be at risk for potassium deficiency.

In addition, a diet that is high in sodium and low in potassium can negatively impact potassium status. While the typical American diet, which is high in sodium-containing processed foods and low in fruits and vegetables, contains about two times more sodium than potassium, many health experts recommend taking in at least five times more potassium than sodium.

The symptoms of potassium deficiency include muscle weakness, confusion, irritability, fatigue, and heart disturbances. Athletes with low potassium stores may tire more easily during exercise, as potassium deficiency causes a decrease in glycogen (the fuel used by exercising muscles) storage.

Toxicity Symptoms

What are toxicity symptoms for potassium?

Elevated blood levels of potassium can be toxic, and may cause an irregular heartbeat or even heart attack. Under most circumstances, the body maintains blood levels of potassium within a tight range, so it is not usually possible to produce symptoms of toxicity through intake of potassium-containing foods and/or supplements.However, high intakes of potassium salts (potassium chloride and potassium bicarbonate) may cause nausea, vomiting, diarrhea, and/or ulcers.

In addition, the kidneys play an important role in eliminating excess potassium from the body, so if you suffer from kidney disease, you must severely limit your intake of potassium. To date, the National Academy of Sciences has not established a Tolerable Upper Intake Level (UL) for potassium.

Impact of Cooking, Storage and Processing

How do cooking, storage, or processing affect potassium?

Potassium losses from cooking of high-potassium foods can be significant. In the case of spinach for example, potassium levels have been shown to drop from 6.9 to 3.0 grams in 3 and 1/2 ounces of spinach after blanching for several minutes (a loss of about 56%).

Sometimes this passage of potassium out of foods can be nutritionally beneficial. For example, parsley tea often contains significant amounts of potassium because this mineral is leached out of the parsley leaves and into the hot tea water.

Factors that Affect Function

What factors might contribute to a deficiency of potassium?

In addition to poor dietary intake, overuse of muscles, as might occur in excessive physical activity, is a factor that can increase a person's need for potassium. Any events that draw excessive fluid out of the body - including excessive sweating, diarrhea, overuse of diuretics (including caffeine-containing beverages), poor water intake, or adherence to a ketogenic diet - can increase the need for potassium.

Since potassium functions in close cooperation with sodium, imbalanced intake of salt (sodium chloride) can also increase a person's need for potassium. Higher amounts of potassium are also needed by persons with high blood pressure.

Drug-Nutrient Interactions

What medications affect potassium?

The following medications may cause an increase in blood levels of potassium:

• Angiotensin-converting enzyme (ACE) inhibitors, such as quinapril, ramipril, enalapril, captopril, are used to treat high blood pressure. These medications may increase potassium levels, especially when taken by individuals with kidney disease.
• Non-steroidal anti-inflammatory medications, such as ibuprofen (Advil) and indomethacin, may cause an increase in blood levels of potassium by damaging the kidneys.
• Heparin, an anticoagulant prescription medication used to prevent blood clots after surgery, may increase potassium levels.
• Sulfonamide antibiotics may increase potassium levels, especially when taken by individuals with kidney disease.

The following medications may cause a decrease in blood levels of potassium:

• Prolonged use of stimulant laxatives, such as those that contain senna, can cause excessive loss of potassium.
• Cisplatin, a chemotherapy medication, may cause excessive loss of potassium.
• Steroidal anti-inflammatory medications, including prednisone and cortisone, increase the loss of potassium in the urine.
• Neomycin, an antibacterial drug, decreases blood levels of potassium by reducing the absorption of dietary potassium and/or increasing urinary excretion of potassium.
• Theopylline and aminopylline, medications used in the treatment of asthma, may promote potassium deficiency.
• Tobramycin, an antibiotic that is administered intravenously, can cause potassium depletion.
• Diuretics, or "water pills", can work to lower blood pressure by increasing urinary excretion of water and therefore lowering the amount of water found in blood. While certain diuretics can "spare" potassium, including amiloride, spironolactone, and triamterene, others diuretics decrease potassium levels. The potassium-decreasing diuretics include the thiazide diuretics like hydrochlorothiazides, and the loop diuretics like furosemide - including the widely know brand name Lasix (TM). Because potassium is essential for many aspects of healthy heart function, risk of heart arrhythmia can be increased by chronic use of these thiazide and loop diuretics, and blood pressure itself may become more difficult to regulate in the long run due to the important role of potassium in blood pressure regulation.

Nutrient Interactions

How do other nutrients interact with potassium?

Through a mechanism known as the "sodium-potassium" pump, sodium and potassium work together closely to initiate muscle contraction and nerve transmission, and to maintain the body's normal distribution of fluid. Most of the potassium in your body is stored inside of your cells, while most of the sodium in your body is stored in the fluid that surrounds your cells.

During muscle contraction and nerve transmission, potassium leaves the cell and sodium enters the cell via the "sodium-potassium pump." This transfer causes a change in electrical charge within the cell, which initiates the muscle contraction or the nerve impulse. Because sodium attracts water, once the muscle contraction or nerve impulse is initiated, the sodium is immediately pumped out of the cell to prevent water from entering the cell and causing the cell to swell or burst, and potassium is pumped back into the cell.

Potassium is known to decrease the excretion of calcium. As a result, increasing the amount of potassium-containing foods in your diet may be helpful in maintaining the density and strength of your bones.

Health Conditions

What health conditions require special emphasis on potassium?

Potassium may play a role in the prevention and/or treatment of the following health conditions:

• Atherosclerosis
• Cataracts
• Dehydration
• Diabetes
• Hepatitis
• High blood pressure
• Inflammatory bowel disease
• Osteoporosis
• Potassium depletion due to excessive fluid loss from diarrhea, vomiting, or sweating

Form in Dietary Supplements

What forms of potassium are found in dietary supplements?

Potassium is found in dietary supplements as potassium salts (potassium chloride and potassium bicarbonate) and potassium chelates (potassium citrate and potassium aspartate). It is also available in food-based supplements. In an attempt to prevent the health problems (see Toxicity Symptoms above) associated with high intakes of potassium salts, the United States Food and Drug Administration restricts the amount of potassium in non-food based supplements to 99 mg per serving.

Food Sources

What foods provide potassium?

Potassium is found in abundance in many foods, and is especially easy to obtain in fruits and vegetables. Excellent sources of potassium include chard, crimini mushrooms, and spinach.

Very good sources of potassium include fennel, kale, mustard greens, Brussel sprouts, broccoli, winter squash, blackstrap molasses, eggplant, cantaloupe, and tomatoes.

Good sources of potassium include parsley, cucumber, bell pepper, turmeric, apricots, ginger root, strawberries, avocado, banana, tuna, halibut, cauliflower and cabbage.

 

Introduction to Nutrient Rating System Chart

In order to better help you identify foods that feature a high concentration of nutrients for the calories they contain, we created a Food Rating System. This system allows us to highlight the foods that are especially rich in particular nutrients. The following chart shows the World's Healthiest Foods that are either an excellent, very good, or good source of potassium. Next to each food name, you'll find the serving size we used to calculate the food's nutrient composition, the calories contained in the serving, the amount of potassium contained in one serving size of the food, the percent Daily Value (DV%) that this amount represents, the nutrient density that we calculated for this food and nutrient, and the rating we established in our rating system. For most of our nutrient ratings, we adopted the government standards for food labeling that are found in the U.S. Food and Drug Administration's "Reference Values for Nutrition Labeling." Read more background information and details of our rating system.

World's Healthiest Foods ranked as quality sources of: potassium
Food	Serving Size	Cals	Amount (mg)	DV (%)	Nutrient Density	World's Healthiest Foods Rating
Swiss chard, boiled	1 cup	35.0	960.75	27.4	14.1	excellent
Romaine lettuce	2 cup	15.7	324.80	9.3	10.7	very good
Crimini mushrooms, raw	5 oz-wt	31.2	635.04	18.1	10.5	excellent
Spinach, boiled	1 cup	41.4	838.80	24.0	10.4	excellent
Celery, raw	1 cup	19.2	344.40	9.8	9.2	very good
Basil, dried, ground	2 tsp	7.5	103.00	2.9	7.0	good
Mustard greens, boiled	1 cup	21.0	282.80	8.1	6.9	very good
Fennel, raw, sliced	1 cup	27.0	360.18	10.3	6.9	very good
Broccoli, steamed	1 cup	43.7	505.44	14.4	6.0	very good
Winter squash, baked, cubes	1 cup	80.0	895.85	25.6	5.8	very good
Cucumbers, slices, with peel	1 cup	13.5	149.76	4.3	5.7	good
Blackstrap molasses	2 tsp	32.1	340.57	9.7	5.5	very good
Tomato, ripe	1 cup	37.8	399.60	11.4	5.4	very good
Turnip greens, cooked	1 cup	28.8	292.32	8.4	5.2	very good
Collard greens, boiled	1 cup	49.4	494.00	14.1	5.1	very good
Summer squash, cooked, slices	1 cup	36.0	345.60	9.9	4.9	very good
Eggplant, cooked, cubes	1 cup	27.7	245.52	7.0	4.6	very good
Cantaloupe, cubes	1 cup	56.0	494.40	14.1	4.5	very good
Green beans, boiled	1 cup	43.8	373.75	10.7	4.4	very good
Kale, boiled	1 cup	36.4	296.40	8.5	4.2	very good
Brussel sprouts, boiled	1 cup	60.8	494.52	14.1	4.2	very good
Carrots, raw	1 cup	52.5	394.06	11.3	3.9	very good
Turmeric, powder	2 tsp	16.0	114.48	3.3	3.7	good
Beets, Boiled	1 cup	74.8	518.50	14.8	3.6	very good
Asparagus, boiled	1 cup	43.2	288.00	8.2	3.4	very good
Papaya	1 each	118.6	781.28	22.3	3.4	very good
Bell peppers, red, raw, slices	1 cup	24.8	162.84	4.7	3.4	good
Cauliflower, boiled	1 cup	28.5	176.08	5.0	3.2	good
Apricots	1 each	16.8	103.60	3.0	3.2	good
Ginger root	1 oz-wt	19.6	117.65	3.4	3.1	good
Yam (Dioscorea species), cubed, cooked	1 cup	157.8	911.20	26.0	3.0	good
Strawberries	1 cup	43.2	239.04	6.8	2.8	good
Kiwifruit	1 each	46.4	252.32	7.2	2.8	good
Chili pepper, dried	2 tsp	25.5	126.00	3.6	2.5	good
Cod, baked/broiled	4 oz-wt	119.1	586.28	16.8	2.5	good
Lima beans, cooked	1 cup	216.2	955.04	27.3	2.3	good
Cabbage, shredded, boiled	1 cup	33.0	145.50	4.2	2.3	good
Banana	1 each	108.6	467.28	13.4	2.2	good
Grapefruit	0.50 each	36.9	158.67	4.5	2.2	good
Onions, raw	1 cup	60.8	251.20	7.2	2.1	good
Halibut, baked/broiled	4 oz-wt	158.8	653.18	18.7	2.1	good
Tuna, yellowfin, baked/broiled	4 oz-wt	157.6	645.25	18.4	2.1	good
Snapper, baked/broiled	4 oz-wt	145.2	591.95	16.9	2.1	good
Oranges	1 each	61.6	237.11	6.8	2.0	good
Potato, baked, with skin	1 cup	133.0	509.96	14.6	2.0	good
Avocado, slices	1 cup	235.1	874.54	25.0	1.9	good
Yogurt, low-fat	1 cup	155.1	572.81	16.4	1.9	good
Watermelon, diced	1 cup	48.6	176.32	5.0	1.9	good
Pinto beans, cooked	1 cup	234.3	800.28	22.9	1.8	good
Green peas, boiled	1 cup	134.4	433.60	12.4	1.7	good
Sweet potato, baked, with skin	1 each	95.4	306.05	8.7	1.7	good
Lentils, cooked	1 cup	229.7	730.62	20.9	1.6	good
Kidney beans, cooked	1 cup	224.8	713.31	20.4	1.6	good
Figs, fresh	8 oz-wt	167.8	526.18	15.0	1.6	good
Plum	1 each	36.3	113.52	3.2	1.6	good
Prunes	0.25 cup	101.6	316.63	9.0	1.6	good
Cow's milk, 2%	1 cup	121.2	376.74	10.8	1.6	good
Raspberries	1 cup	60.3	186.96	5.3	1.6	good
Split peas, cooked	1 cup	231.3	709.52	20.3	1.6	good
Soybeans, cooked	1 cup	297.6	885.80	25.3	1.5	good
Goat's milk	1 cup	167.9	498.74	14.2	1.5	good
Scallops, baked/broiled	4 oz-wt	151.7	444.46	12.7	1.5	good
Grapes	1 cup	61.6	175.72	5.0	1.5	good

World's Healthiest Foods Rating	Rule
excellent	DV>=75%	OR	Density>=7.6	AND	DV>=10%
very good	DV>=50%	OR	Density>=3.4	AND	DV>=5%
good	DV>=25%	OR	Density>=1.5	AND	DV>=2.5%

Public Health Recommendations

What are current public health recommendations for potassium?

In 2004, the Institute of Medicine at the National Academy of Sciences issued new Adequate Intake (AI) levels for potassium. The recommendations are as follows:

• 0-6 months: 400 mg
• 6-12 months: 700 mg
• 1-3 years: 3.5 g
• 4-8 years: 3.8 g
• 9-13 years: 4.5 g
• 14-18 years: 4.5 g
• 19-30 years: 4.7 g
• 31-50 years: 4.7 g
• 51+ years: 4.7 g
• Pregnant women: 4.7 g
• Lactating women: 5.1 g

References

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• Fedida D, Hesketh JC. Gating of voltage-dependent potassium channels. Prog Biophys Mol Biol 2001;75(3):165-99 2001. PMID:15870.
• Griffith LC. Potassium channels: the importance of transport signals. Curr Biol 2001 Mar 20;11(6):R226-8 2001. PMID:15880.
• Groff JL, Gropper SS, Hunt SM. Advanced Nutrition and Human Metabolism. West Publishing Company, New York, 1995 1995.
• He FJ, MacGregor GA. Fortnightly review: Beneficial effects of potassium. BMJ 2001 Sep 1;323(7311):497-501 2001. PMID:15850.
• Lininger SW, et al. A-Z guide to drug-herb-vitamin interactions. Prima Health, Rocklin, CA, 2000 2000.
• Sellmeyer DE, Schloetter DE, Schloetter M et al. Potassium citrate prevents urine calcium excretion and bone resorption induced by a high sodium chloride diet. J Clin Endo Metab 2002;87(5):2008-12 2002.
• Sigworth FJ. Potassium channel mechanics. Neuron 2001 Nov 20;32(4):555-6 2001. PMID:15840.
• Sobey CG. Potassium channel function in vascular disease. Arterioscler Thromb Vasc Biol 2001 Jan;21(1):28-38 2001. PMID:15890.

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