Potassium (Kalium)

Recommended Daily Intake

Recommended Dietary Allowance (RDA) for potassium has not been set yet due to lack of scientific evidence.

Adequate intake (AI) for potassium for adults–the intake probably sufficient for most healthy adults–has been set at 4.7 g/day. In some studies, this or higher intakes were associated with a lower risk of blood pressure and kidney stones ^[1,4].

Chart 1. Adequate Intake (AI) for potassium
AGE	AI (g/day)
Infants 0-6 months	0.4*
Infants 7-12 months	0.7
1-3 years	3
4-8 years	3.8
9-13 years	4.5
14+ years, including pregnant women	4.7
Breastfeeding women	5.1

Chart 1 source: Institute of Medicine (IOM) in the U.S. ^[4]  *Breast milk of healthy mothers should provide enough potassium for exclusively breastfed infants 0-6 months of age ^[4,5]. 

Foods High in Potassium

The major potassium sources are fruits and vegetables. Common foods rich in potassium include potatoes, kiwifruits, avocados, bananas, green leafy vegetables, beans, beef, pork, fish, milk and “low-sodium” products.

Picture 1. Examples of potassium-rich foods

Chart 2. List of Foods High in Potassium (>200 mg/serving)
PLANT FOODS	POTASSIUM (mg)
Fruits
Dried fruits: apricots, peaches, prunes (1/2 cup, ~60 g)	650-750
Avocado, jackfruit, pomegranate (1 medium fruit); guava (1 cup)	700
Fruit juice: carrot, prune juice (1 cup, 237 mL)	650-700
Dates, medjool (4 pieces, 100 g)	650
Kiwi fruit (1 cup sliced, 180 g)	550
Banana (8 inch, 140 g), figs, dried (1/2 cup, 75 g)	500
Fruit juices: grape, grapefruit, orange, pineapple; vegetable juices (1 cup, 237 mL)	350-500
Cantaloupe (1/2 cup, 160 g)	450
Fruits: grape, grapefruit, orange, nectarine, papaya, peach, pear, persimmon, pineapple, watermelon (1 medium fruit or 1 cup)	300-400
Vegetables, Beans, Nuts
Chestnut, Japanese, dried (1 cup, 155 g)	1,200
Potato, with skin, baked, sweet potato, yam (2-3″ dia, 170 g)	900-950
Tamarind (1 cup)	700-750
Potato, without skin (2-3″ dia, 170 g); cassava, raw (1 cup, 200 g)	550
Beet greens (1/2 cup, 72 g)	650
White beans, adzuki beans, canned; soybeans (1/2 cup, ~120 g) (canned beans can contain >300 mg sodium)	500-600
Coconut water or milk (1 cup, 237 mL)	500-600
Squash, winter; spinach, Swiss chard (1/2 cup, 100 g), tomatoes, red (1 cup, 180 g)	400-500
Legumes: beans (black, lima, kidney, navy, northern, pink, pinto, split); lentils (1/2 cup, ~100 g) (canned beans can contain >300 mg sodium)	350-400
Artichokes (globe/French/Jerusalem), beets, broccoli, bok choy, Brussel’s sprouts, cabbage, celery, kohlrabi, parsnips (1/2 cup), dandelion (raw, 1 cup); Mushrooms, white (1/2 cup, 80 g)	200-300
Other
Dark chocolate (1 bar, 2.6 oz, 75 g)	350
Cereals, ready-to-eat (1 cup, ~30 g prepared with water)	20-350
Quinoa (1 cup, 185 g)	300
Blackstrap molasses (1 tbsp, 20 g)	300
Snacks: seeds, dried kernels: pumpkin, squash, sunflower; pistachios; peanut butter; raisins (1 oz, 28 g), granola bar (2 oz, 57 g)	250-300
ANIMAL FOODS
Salmon, red, smoked (3 oz, 85 g) (canned salmon can contain >500 mg sodium)	800
Fish: cod, halibut, pollock, salmon (Atlantic, wild); sardines, tuna (yellowfin, skipjack) (3 oz, 85 g); clams; oysters  (canned fish can contain >300 mg sodium)	400-500
Soup, beef (1 cup,237 mL)  (can contain >450 mg sodium)	400
Yogurt, plain (1 container, 6 oz, 170 g)	400
Meat: beef, bison, goat, pork (3 oz, 85 g)  (beef can contain > 9 g saturated fat)	300-400
Milk, whole (1 cup, 237 mL)  (5 g saturated fat)	350
Seafood: haddock, mackerel, perch, salmon, [chum, pink, sockeye], tuna [white, canned; bluefin]; crab/blue; mussels, shrimps, squid (3 oz, 85 g)  (canned fish can contain >300 mg sodium)	200-300

Chart 2. source: U.S. Department of Agriculture (USDA.gov) ^[5] NOTE: All foods listed are ready to eat.

Potassium Chloride as a Salt Substitute

Potassium chloride is often used as a sodium-free substitute for table salt. It is also used in “low-sodium” and “no sodium” foods, as a food additive in commercial foods and as a potassium supplement. 1 gram of potassium chloride contains about 500 mg (0.5 g) of potassium.

Taking potassium chloride instead of table salt to increase potassium and decrease sodium intake is generally not recommended; you should rather limit sodium intake and eat foods high in potassium.

Can potassium chloride be dangerous?

Large amounts of potassium chloride can cause stomach or intestinal ulcers and bleeding; taking more than 10 grams (2 teaspoons) at once can cause hyperkalemia ^[1,24].

Absorption and Excretion

From the ingested potassium, about 90% is absorbed, mainly in the small intestine. Most of the excessive potassium is excreted through the urine and only small amounts via feces and sweat ^[24,32].

Potassium and Coronary Heart Disease

In the abovementioned review performed by researchers from WHO, high potassium intake was not associated with decreased risk of coronary heart disease ^[12].

Can high-potassium diet be bad for you?

The Tolerable Upper Intake Level (UL) for potassium–the maximal amount unlikely to cause side effects in healthy people–has not been set, because no adverse effects from high dietary potassium intake have not been reported ^[1]. Individuals with chronic kidney disease, Addison’s disease and those who take potassium-sparing diuretics (amiloride, spironolactone, triamterene) may need to limit potassium intake, though.

A Low-Potassium Diet in Chronic Kidney Disease

If you have a chronic kidney disease, especially if you are on hemodialysis, a doctor may prescribe you a low potassium diet with less than 1.5-2.7 grams of potassium per day, along with a low-phosphorus (800-1,000 mg/day) and low sodium (<2.4 g/day) diet ^[6].

Chart 3. List of foods low in potassium (<200 mg/serving), phosphorus (<100 mg/serving) and sodium (<500 mg/serving)
PLANT FOODS	POTASSIUM (mg)
Cereals
Cornmeal, degermed, cooked (1 cup, 160 g)	200
Oatmeal, buckwheat groats, barley (pearled), bulgur (1 cup, prepared with water)	150
Corn flakes, corn grits, couscous, farina, rice crisps (1 cup, cooked with water)	20-100
Bread: French, Italian, pumpernickel, raisin, white, whole-grain (2 slices, 60 g)	60-90
Cookies, pretzels, cakes and pastries without nuts or chocolate (3 oz, 85 g)	50-150
Peas, green, boiled (1/2 cup, 80 g)	200
Pasta: macaroni, noodles, spaghetti (1 cup, 140 g)	30-60
Rice (white), tapioca (pearl, dry), arrowroot flour (1 cup, 152 g)	20
Fruits
Apple, blackberries, blueberries, boysenberries, cherries, clementine, currants, gooseberries, grapes (American type), kumquat, lemon, litchis, mango, pear, pineapple, plums, raspberries, strawberries, tangerine (mandarin orange), watermelon (1 fruit or 1/2 cup)	100-200
Cranberries, lime (1 fruit or 1/2 cup)	50-90
Vegetables, Beans, Nuts
Asparagus, cabbage, carrots, chayote, collards, kale, mustard greens, okra, onions, radish, rhubarb, squash (summer, zucchini), turnips, turnip greens, watercress (1/2 cup cooked)	100-200
Alfalfa, bamboo, shoots, cauliflower, corn (canned), cucumbers (raw, pickled), eggplant, leeks, lettuce, peppers, water chestnut, mushrooms, watercress (1/2 cup)	20-100
Nuts: acorns, almonds, Brazil nuts, cashews, coconut, hazelnuts, macadamia, peanuts, pecans, pili nuts, pine, walnuts (1 oz, 28 g)	100-200
Other
Wine (1 glass, 5 oz, 150 mL)	100-200
Beans, garbanzo (chickpeas), snap, green/yellow (1/2 cup, 60 g)	80-150
Coffee, black tea (1 cup, 8 oz, 237 mL)–limit to 1 cup/day	100
Malt syrup (1 tbsp, 21 g)	70
Spices: anise, chili, coriander, cumin, curry, dill, fennel, garlic, ginger, mustard, nutmeg, onion, paprika, pepper, turmeric (1 tsp)	20-50
Syrups: cane, corn, grenadine, maple (1 tbsp, 20 g)	10-40
Municipal water, herbal tea, carbonated beverages (club soda, ginger ale, lemon-lime, mineral water, orange, tonic water, root beer) (1 cup, 237 mL), table sugar, white/brown (1 tsp, 3 g), candies, hard, jellybeans, toffee (1 oz, 28 g), vinegar, vegetable oils, all types, margarine, butter, jam (1 tbsp, 15 g)	0-20
ANIMAL FOODS
Chicken, turkey; tuna, light (canned in oil) (3 oz, 85 g)	100-200
Cheese: cream, cottage, ricotta (2 tbsp, 30 g)	30-100
Salad dressing: caesar, Italian, mayonnaise, French, Russian; cream, liquid, half and half; sour cream (2 tbsp, 30 g)	20-50
Honey (1 tbsp, 20 g)	10

Chart 3. source: U.S. Department of Agriculture (USDA) ^[5]

Tips to lower potassium in your diet:

• Peel vegetables, cut them to thin slices, put them into a large amount of water and bring the water to a boil. Discard the water and boil again in fresh water until cooked (double boiling). This way more potassium will leak into the water than with single boiling. Dry heating (baking, roasting, microwaving) and steaming (cooking in vapor) does not significantly reduce the amount of potassium in foods ^[7].
• Leaching for 2 hours or overnight in a large amount of warm water before cooking can also pull some potassium out of vegetables ^[6].
• Do not drink liquids from canned foods or cooked meat (beef soup).
• Avoid foods that list potassium additives on nutrition labels.

Normal Blood Potassium Levels Range

Normal blood potassium levels range from 3.5 to 5.1 mmol/liter (the upper limit may differ from 5.0 to 5.5 among laboratories) ^[19].

Regulation of Blood Potassium Levels

• High blood potassium levels stimulate the adrenal gland to release the hormone aldosterone, which stimulates potassium excretion into the urine.
• A drop of blood pH (acidosis) stimulates potassium retention, and a raise of blood pH (alkalosis) stimulates its excretion into the urine.
• Reference: ³⁴

Potassium Supplements

Potassium supplements are available only by prescription. In the U.S., potassium may be found in certain over-the-counter (OTC) multivitamin/mineral supplements but only in doses up to 99 mg per tablet, which is usually not enough to treat hypokalemia.

Available oral forms:

Potassium chloride is available in the form of tablets, effervescent tablets or granules, capsules and liquids.

• Potassium liquid and powder for solution are intended for those who have problem with swallowing tablets.
• Potassium chloride extended release (KCl Er) tablets and capsules are slow-release supplements that were designed to minimize the risk of gastrointestinal damage. Wax matrix and microencapsulated formulations are available but the differences in their effectiveness are not yet clear ^[25].
• Enteric-coated (EC KCl) tablets are no longer commercially available in the U.S. because of possible severe gastrointestinal side effects.

Alkalizing supplements–potassium bicarbonate, citrate and gluconate–are used to treat hypokalemia associated with acidosis (low blood pH) or to prevent calcium-oxalate kidney stones ^[25,30].

Magnesium potassium aspartate is used as a magnesium and potassium supplement.

Potassium orotate has been occasionally used to treat anxiety ^[18].

Potassium chelate is a general term for over-the-counter supplements in which potassium is bound to larger molecules, such as amino acids. One tablet usually contains 99 mg potassium.

Intravenous injection:

Potassium chloride, acetate or gluconate are used to treat severe hypokalemia ^[21,25].

Dosage

The amount of potassium listed on the supplement packages is expressed either in milliequivalents (meq)–which is the same as millimoles (mmol)–or in milligrams (mg). To convert meq or mmol to mg, multiply meq or mmol by 39.1. The usual doses of oral supplements for adults are 15-30 meq (587-1,173 mg), 2 times per day or up to total 100 meq (3,900 mg) per day but it is your doctor who can prescribe the dose appropriate for you ^[17].

Potassium supplements are NOT EFFECTIVE for prevention of high blood pressure, neither alone or in combination with calcium or magnesium ^[9,10,16].

There is INSUFFICIENT EVIDENCE about potassium supplements effectiveness in prevention or treatment of acne, alcoholism, allergies, Alzheimer’s disease, bloating, blurred vision, cancer, chronic fatigue syndrome (CFS), colitis, constipation, dermatitis, fever, gout, headaches, heart attack, insomnia, infectious mononucleosis, insulin resistance, irritability, Menière’s disease (a type of dizziness), mood swings in menopause, muscle weakness, muscular dystrophy, myasthenia gravis, rheumatoid arthritis, stress, stroke and thallium poisoning ^[16].

Which supplement is the best?

• The percent of absorption and bioavailability of various potassium supplements is probably about the same ^[31].
• Potassium chloride is usually used to treat potassium deficiency, and alkaline supplements (potassium citrate, bicarbonate, gluconate or acetate) to treat acidosis (low blood pH) or to prevent kidney stones.

Supplements Safety: Side Effects, Dangers, Toxicity

Side effects of oral potassium supplements may include nausea, vomiting, abdominal discomfort, diarrhea and, rarely, intestinal ulcers with blood in the stool or even perforation of the intestine ^[16,24]. Intravenous potassium chloride can irritate the veins and cause local pain.

During Pregnancy

According to the U.S. Food and Drug Administration (FDA), potassium is pregnancy category drug C, which means, harmful effects for the babies have not been confirmed but can not be excluded due to lack of human trials ^[17]. According to Natural Medicines Comprehensive Database, potassium in doses up to 80 meq per day is likely safe to use during pregnancy and breastfeeding ^[16].

Overdose

5.5 grams of potassium in a single dose can cause hyperkalemia and 18 grams or more can result in severe hyperkalemia, which may result in abnormal heart rhythm (arrhythmia), nervousness, confusion, lethargy, numbness and tingling in hands and around the lips, difficulty breathing, delirium, heart attack or even death ^[17,24,29].

Allergy

Certain potassium supplements contain tartrazine, which can trigger allergic reaction in sensitive individuals ^[16].

Who should avoid potassium supplements?

Individuals who have hyperkalemia, kidney disease with potassium retention, Addison’s disease or those who take potassium-sparing diuretics should avoid potassium supplements. Anyone with swallowing problems or impaired intestinal motility should avoid solid potassium forms (tablets, capsules).

Other Potassium Uses

• Potassium phosphate is used as a phosphorus supplement.
• Acesulfame-K is a potassium containing non-caloric sweetener.
• Various potassium compounds are used as food additives.

Potassium Water Softeners

Potassium chloride pellets are used as water softeners. The potassium in water treated with softeners does not likely affect blood potassium levels in healthy individuals but can cause hyperkalemia in individuals with kidney disease or in those taking potassium-sparing diuretics (amiloride, spironolactone, triamterene). According to Health Canada, water with hardness 100 treated by potassium chloride can contain about 80 mg of potassium per liter and water with hardness 500 about 400 mg of potassium per liter ^[29].

Frequently Asked Questions

1. Can you get too much potassium by eating bananas?

Eating a lot of bananas or other high-potassium foods should not cause any potassium-related side effects in healthy people, but it could raise blood potassium levels in individuals with chronic kidney disease or in those taking certain diuretics (amiloride, spironolactone, triamterene).

2. Do I need potassium supplements if I am on a low-carb diet?

Probably not. In the first days of a low-carb diet, about 500 grams of glycogen and about 9 grams of potassium bound to it is lost ^[11]. You can simply replace this amount of potassium by eating potassium-rich foods.

3. Do I need to replace potassium during marathon running?

No. In one small study, marathoners, after running 20 miles, did not have decreased blood potassium levels ^[35,p.226]. The potassium loss with sweat can be as high as 500 mg per liter of sweat, but can decrease considerably after several days of heat acclimation ^[35,p.226]. Runners can easily replace the lost potassium by eating common foods after the race, so they do not need potassium supplements or sport drinks during the race.

4. Do I need to follow a low-potassium diet if I have a sensitive bladder (interstitial cystitis)?

Some doctors recommend avoiding high-potassium and acidic foods (tomatoes, citrus fruit juices, etc.) to individuals with interstitial cystitis, but not a low-potassium diet because of the risk of potassium deficiency ^[40].

5. Does hypokalemia cause eye twitching?

Eyelid twitching might be a symptom of hypokalemia, but fatigue, stress and caffeine overdose are much more likely causes.

6. Is potassium a diuretic and can it be used to treat water retention?

Potassium acts as a mild diuretic, but potassium supplements are not used to treat water retention. For individuals with mild congestive heart failure or other cause of water retention, doctors usually prescribe a high-potassium, low-sodium and fluid-restricted diet ^[37]. For more severe water retention, doctors can prescribe diuretics along with potassium, but in this case, potassium is used to prevent hypokalemia caused by diuretics and not specifically to treat water retention.

7. Is potassium alkalizing or acidifying?

Potassium naturally present in foods is usually in the form of potassium citrate, which alkalizes the urine, which may help prevent calcium-oxalate kidney stones.

8. Does vitamin K contain potassium?

No. The name vitamin K comes from the German word “Koagulationsvitamin,” and the potassium symbol K from the Latin “kalium.” The two “Ks” have nothing in common.