Potassium is one of the major minerals that your body needs in large amounts in order to continue functioning properly. It’s widely available in a diverse array of foods. But despite its abundance, statistics show that less than 3 percent of the U.S. population is actually getting the recommended daily intake for potassium.
The widespread deficiency in potassium even prompted the Dietary Guidelines Advisory Committee to declare it as a nutrient of public health concern in 2015.1,2 Read on to learn why potassium is such an important mineral and how can you avoid being deficient in it.
What Is Potassium?
Sometimes referred to as the “good salt,” potassium is a mineral that helps support a variety of essential body functions, including the contraction of muscles, regulation of body fluids, transmission of nerve impulses, and maintenance of normal blood pressure and blood sugar levels. It also helps balance your body’s chemical and electrical processes, since it’s an electrolyte.
Since your body does not have the ability to produce potassium naturally, one of the ways for you to maintain optimum levels of it is to eat potassium-rich foods, such as beet greens, wild salmon, dried apricots and plain yogurt, to name a few.3 Unfortunately, today’s standard American diet, which commonly consists of unhealthy processed foods, doesn’t really provide much of this nutrient.
Ideally, an adult with healthy kidneys should consume 4,700 milligrams (mg) of potassium daily. Since there is insufficient data on what the Recommended Daily Allowance (RDA) for potassium should be, a panel convened by the National Institutes of Health in 2005 determined that 4,700 mg is an Adequate Intake (AI) for U.S. adults.
The panel said they based their recommendation on studies that show potassium obtained from your diet may help “lower blood pressure levels, reduce the adverse effects of sodium chloride intake on blood pressure, reduce the risk of kidney stones and possibly decrease bone loss.”4 The panel added:
"Overall, because of the concern for hyperkalemia and resultant arrhythmias that might be life-threatening, the proposed AI should not be applied to individuals with chronic kidney disease, heart failure or type 1 diabetes, especially those who concomitantly use ACE inhibitor therapy."
Aside from cautioning not to go over 4,700 mg of potassium a day if you have kidney disease or take ACE inhibitors, the panel did not specify an AI for you. However, according to the National Kidney Foundation, if you have renal disease you should limit your potassium to about 2,000 mg a day.5
The panel advised that, preferably, you should get your potassium from dietary sources, such as vegetables, fruits and root vegetables. Spinach, cantaloupe, dry roasted almonds, Brussels sprouts and mushrooms are just a sample of the foods that have high amounts of potassium. Consult the graph later on in this article for more high-potassium foods.6
Running low on potassium may cause heart palpitations and make you feel nauseous and weak,7 so if you can’t obtain enough potassium from your diet, you may also opt to take potassium supplements. But before you do so, I suggest that you consult your physician first, since excessive intake of this mineral may compromise your health too.8
A Closer Look at the Different Potassium Levels
The normal amount of potassium in the blood ranges from 3.5 to 5.2 millimoles per liter (mmol/L).9 If your body’s potassium levels go below or above this range, then you may experience the following conditions:
• Hypokalemia: Characterized by potassium levels that fall below 3.5 mmol/L, hypokalemia may be caused by a low-potassium diet. It may also be a side effect of other underlying health problems, such as dehydration, diarrhea and excessive sweating (hyperhidrosis).10
• Hyperkalemia: A condition wherein the potassium levels exceed 5.2 mmol/L, hyperkalemia is usually caused by a high-potassium diet or excessive intake of potassium supplements. People with kidney disorders, Addison's disease and diabetes may also be at a higher risk of developing this condition.11
The symptoms of low or high potassium levels are usually mild and nonspecific, making them hard to diagnose. To make a proper diagnosis, your physician may conduct a blood test and a complete physical checkup.12,13
Look Out for the Telltale Signs of Potassium Deficiency
According to a study published in the American Family Physician Journal, 21 percent of hospitalized patients have hypokalemia.14 You can avoid becoming another statistic by watching out for the following warning signs of low potassium levels:15,16
Seek immediate medical attention if you experience any of the symptoms mentioned above, as a delay in treatment may cause severe potassium deficiency. Potassium levels lower than 2.5 mmol/L are considered life-threatening and may cause paralysis, respiratory failure, breakdown of muscle tissue and ileus (also known as lazy bowel).17 Severely low levels of potassium may also increase your risk of heart attack and stroke.18
Get Your Daily Fill of Potassium From These Sources
When it comes to increasing your potassium levels through diet, one of the first foods that may come to mind are bananas — one medium banana contains 422 mg of potassium. However, bananas are far from being your only source of potassium, since you can also obtain this nutrient from the following foods:19
Beet greens: Provides 654 mg of potassium per half-cup.
Swiss chard: Contains 962 mg of potassium per cup.
Acorn squash: Provides 996 mg of potassium per cup.
Avocado: Contains 364 mg of potassium per half-cup.
Spinach: Contains 740 to 838 mg of potassium per cup.
Baked potato, flesh and skin: Contains 941 mg in one medium potato.
Wild-caught Alaskan salmon: Provides 534 mg of potassium per 3-ounce serving.
Plain yogurt: Contains 579 mg of potassium per cup.
Potential Health Benefits That You Can Get From Potassium
• Improved cardiovascular health: Aside from stimulating regular heart contractions, potassium may also help counteract the negative effects of a high sodium diet to your heart, thereby lowering your risk of high blood pressure, stroke and other cardiovascular diseases.
• Healthier bones and muscles: Potassium helps maintain an alkaline environment in the body, which plays a role in promoting bone health and preserving lean muscle mass, efficiently reducing your risk of muscle wasting and loss of bone mineral density.
• Improved kidney and adrenal functions: Low potassium intake has been linked to kidney and adrenal disorders, such as kidney stones and Addison’s disease, so increasing your body’s levels of this mineral may help sustain normal kidney and adrenal function. (If you have renal disease or kidney failure, however, your doctor may advise you to limit your potassium intake.)
Numerous Studies Underscore Potassium’s Benefits
There have been numerous studies regarding the health benefits of potassium, most of which are focused on its ability to help promote cardiovascular health. For instance, a population study conducted in 1982 suggested that higher potassium intake may reduce systolic blood pressure levels by 2 to 3 mmHg,24 which may help lower the coronary heart disease and stroke mortality rate by 4 percent and 6 percent, respectively.25,26
A more recent study published in the Journal of the American College of Cardiology also confirmed that higher dietary potassium intake is indeed associated with a reduced incidence of stroke, coronary heart disease and cardiovascular disease.27 Research also suggests that potassium may play a role in glucose control, as mounting epidemiological evidence from the last decades shows that low dietary potassium intake is related to an increased risk for insulin resistance and/or diabetes.28
What’s the Right Dosage of Potassium for Your Needs?
As mentioned above, healthy adults should limit their potassium intake to 4,700 mg daily. If you’re planning to replenish your body’s potassium levels by taking a dietary supplement, then make sure that you consult your physician first.
Dietary supplements usually contain less than 100 mg of potassium, and the usual dosage for adults is 40 to 80 milliequivalents (mEq) daily, divided into smaller doses throughout the day.29 Keep in mind that the dosage may also vary depending on your health condition, the strength of the supplement and the time between each dose.30
Make sure that you take a potassium supplement only as directed by your doctor. Taking too high a dose may put you at risk of hyperkalemia.31
Possible Side Effects That You May Encounter When Taking a Potassium Supplement
Allergic reactions, like rashes and itching
Potassium may also interact with other medications, particularly nonsteroidal anti-inflammatory drugs (NSAIDs) and angiotensin converting enzyme (ACE) inhibitors, so it’s best to steer clear of these medicines or, if you must take them, consult with your physician about how much potassium you should be consuming.
Moreover, people with kidney disease, heart problems, diabetes, Addison’s disease or stomach ulcers should consult a doctor before taking potassium supplements or increasing their dietary potassium intake.35
Why It’s Best to Get Your Daily Dose of Potassium From Foods
There are many reasons why you should get potassium from foods. First, dietary sources provide higher amounts of potassium than supplements, so you’re likely to get more of this mineral from a cup of beet greens than a dose of potassium supplement.36 The dietary forms of potassium, such as potassium citrate or potassium malate, are also more beneficial than that found in supplemental potassium, since they help your body produce alkali, which leads to better bone health and muscle mass.
Getting potassium from foods also helps you balance other nutrient levels, which may further improve your overall well-being. That said, I suggest that you incorporate more fruits and vegetables into your diet to replenish your body’s potassium levels naturally. Potassium supplements may be considered if you have an underlying health condition that keeps your body from absorbing nutrients or prevents you from consuming potassium-rich foods.37
Frequently Asked Questions (FAQs) About Potassium
Q: What are the foods that contain high amounts of potassium?
A: Aside from bananas, some of the best potassium-rich foods that you should include into your diet are beet greens, Swiss chard and spinach. Other excellent sources of potassium include avocados, wild-caught Alaskan salmon, carrots, broccoli and Brussels sprouts, among others.
Q: How much potassium is in a banana?
A: One medium banana contains 422 mg of potassium.
Q: What does potassium do?
A: Potassium is an electrolyte, which helps balance the chemical and electrical processes in your body. It may also be used for improving your cardiovascular health, since it helps reduce blood pressure levels and support regular heart contractions. Potassium is also good for maintaining optimal bone and muscle mass.
Q: What causes low potassium levels?
A: Low potassium or hypokalemia is usually caused by a low-potassium diet, use of diuretics or laxatives, diarrhea and/or vomiting. It may also be caused by other health problems, such as kidney diseases and eating disorders.38
Q: What causes high potassium levels?
A: High potassium or hyperkalemia may be caused by excessive intake of potassium supplement or a high-potassium diet. It may also be caused by kidney dysfunction and diseases of the adrenal gland.39
Q: Is potassium a metal?
A: Yes, potassium belongs to the alkali group of metals.40