Potassium 101: What is its Role in The Body?

Potassium is an essential mineral for healthy bodily functioning. Potassium has been deemed a “nutrient of public health concern" due to its overall low consumption in the United States and its important role in physiology. This article will discuss what potassium is, its role in the body, how to test for it, and how to ensure proper levels in your body.

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What is Potassium?

The seventh most abundant mineral in the earth's crust, potassium has been historically used in gunpowder, soap making, and as a dye. Minerals containing potassium are found in rocks and are sources of potassium salts as well as clay and wood ash. Today, potassium is most commonly used for fertilizers, although other uses include the making of glass, pharmaceutical drugs, detergents, and liquid soaps.

What is Potassium's Role in The Body?

Potassium works closely with sodium in a mechanism referred to as the sodium-potassium pump. Potassium is the primary ion inside the cells, while sodium is the primary ion outside the cells. The sodium-potassium pump exchanges sodium and potassium, and the difference in levels outside and inside the cell creates an electrochemical gradient, which plays an essential role in how cells talk to each other and thus can affect a wide array of physiological processes in the body, especially kidney filtering, male fertility, brain and heart functioning.

Kidneys

In the cells of the kidneys, there are 50 million sodium-potassium pumps per cell. These pumps are essential for properly filtering waste products and reabsorbing blood sugar and amino acids into the blood. These pumps are also important for electrolyte and pH balance.

Male Fertility

Sodium potassium pumps are required for sperm production and function. These pumps can affect the movement of sperm and also the ability of sperm to penetrate an egg.

Brain Functioning

Sodium potassium pumps are necessary for neurons, or brain cells, to communicate properly. Additionally, these pumps can affect the number of neurotransmitters.

Heart Functioning

The sodium-potassium pump in cardiac cells can affect the contractility, or pumping action, of the heart.

Parathyroid Hormone

Sodium potassium pumps may also play a role in the progression of hyperparathyroidism. Hyperparathyroidism is a condition of the parathyroid glands releasing too much parathyroid hormone (PTH), leading to increased calcium release from the bones and teeth enamel. This elevation in calcium in the blood can then be detrimental to the heart and other organs. Excessive PTH can cause an increase in the number of sodium-potassium pumps, which may result in excessive sweating and heat intolerance, and increased weight loss. The excessive amount of pumps will also increase the basal metabolic rate (BMR), resulting in increased body temperature, respiratory rate, energy production, and oxygen consumption.

Cofactor for Enzymes

A limited number of enzymes require the presence of potassium for their activity, including pyruvate kinase, an important enzyme in carbohydrate metabolism.

How to Test Potassium Levels

Potassium levels can be checked in the blood and urine. In the blood, potassium can be assessed in the serum or inside the red blood cell. Serum testing, such as the test by Access Medical Laboratories, assesses potassium levels in the fluid of the blood or the serum. Potassium levels in serum testing should be between 3.70 to 5.20 millimoles per L (mm/L). Vibrant America offers a potassium RBC test that assesses intracellular levels of potassium, where most potassium is stored.

Potassium levels may be a part of micronutrient tests such as the Micronutrients panel by Vibrant America. Additionally, potassium can be found in Comprehensive Metabolic Panels (CMPs). CMPs, such as Access Medical Laboratories CMP, assess blood sugar, kidney, and liver markers, as well as electrolytes. Basic Metabolic Profiles (BMPs), like the BMP offered by Vibrant America, are similar to a CMP, except it does not include liver function markers, but it does also include potassium. Lastly, an electrolyte panel, such as the test offered by Boston Heart Diagnostics, evaluates electrolyte levels, including potassium.

Access Medical Laboratories offers a random potassium urine test, where potassium levels should be below 20 milliequivalents per liter (mEq/L), and a 24-hour potassium urine collection test with a range of 25 to 125 mEq per day.

Low potassium levels can increase the risk of kidney stones and change the reactivity to salt, leading to increased sensitivity to the blood pressure response of salt. Additionally, lower potassium levels can cause bone turnover, calcium excretion in the urine, and increased blood pressure.

What is Hypokalemia?

Hypokalemia is the term for potassium deficiency, defined as a serum potassium level of less than 3.6 mmol/L. People with inflammatory bowel disease, pica, and those who take certain medications are at a greater risk for hypokalemia. Hypokalemia can be the result of diarrhea, vomiting, diuretics, laxatives, dialysis, intense sweating, and eating clay. Because of the physiological activities of potassium, specifically its movement into the cell, hypokalemia can result from refeeding after a period of starvation, putting those with distorted eating patterns also at risk. 21% of hospitalizations will lead to hypokalemia due to the use of various medications. Symptoms of mild hypokalemia are constipation, fatigue and malaise, and muscle weakness. Moderate to severe hypokalemia can cause blood sugar intolerance, excessive urine output, muscle paralysis, breathing dysfunction, and cardiac arrhythmias. Those with existing kidney disease may also experience encephalopathy. More than 50% of those with hypokalemia may also have low magnesium levels, making matters worse. Low levels of magnesium may exacerbate hypokalemia as low magnesium will cause increased potassium excretion in the urine. Concurrent low magnesium and low potassium create an even greater increased risk for cardiac arrhythmias.

What is Hyperkalemia?

Hyperkalemia is the term given to high potassium levels. It is thought that dietary potassium cannot cause hyperkalemia in healthy individuals due to the tightly controlled physiological maintenance of potassium levels: excess potassium will always get excreted by the kidneys in the urine. Most of the time, this principle also applies to potassium supplementation; however, hyperkalemia can occur in healthy individuals in the presence of chronically high potassium supplement intake. Hyperkalemia is achievable even with dietary potassium intakes below normal levels in people with kidney conditions and those taking certain blood pressure medications. Type 1 diabetics, people with liver disease, adrenal insufficiency, and congestive heart failure are also at risk for hyperkalemia. Hyperkalemia can present symptomless. However, severe hyperkalemia can manifest as heart palpitations, muscle weakness, and burning and prickling sensations in the arms and legs. Severe hyperkalemia can also lead to cardiac arrhythmias and death.

How to Make Sure You Are Getting Enough Potassium in Your Diet

The National Academies of Sciences, Engineering, and Medicine formed a Food and Nutrition Board, which created Dietary Reference Intakes (DRIs) in relation to vitamins and minerals. One DRI is the Recommended Dietary Allowance (RDA), a value equating to the average daily amount of a vitamin or mineral that would meet the nutritional requirements of most healthy people. However, if there is a lack of evidence for formulating RDAs, Adequate Intake (AI) levels are formed, which are described as the levels assumed to reach nutritional requirements.

Potassium AIs

Recommendations for pregnant and lactating women are often different. The AI for pregnant women aged 14 to 18 years old is 2,600 mg and 2,900 mg for women 19 to 50 years old. The AI for lactating women aged 14 to 18 years old is 2,500mg and 2,800 mg for 19 to 50 year olds.

Potassium sources include food and supplements.

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Top 10 Potassium-Containing Foods

Additionally, salt replacement products usually replace sodium with potassium. These products can serve as a large source of potassium. Those at higher risk for hyperkalemia are suggested to consult with their physician prior to consumption of these products.

Supplements

Potassium is included as stand-alone supplements as well as parts of some multivitamins. Potassium chloride is the most common form of potassium found in supplements; however, other types, such as potassium citrate, phosphate, aspartate, bicarbonate, and gluconate, can be found. The amount of potassium in any given supplement usually does not exceed 99 mg, as the Federal Drug Administration (FDA) has deemed this dosage unsafe due to an association with small bowel lesions. Potassium-containing supplements may cause gastrointestinal distress.

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Summary

Potassium is an essential nutrient necessary for life. The potassium-dependent physiological processes in the body are of utmost importance and signify why potassium levels in the body must be maintained. As potassium intake has been deemed low in the United States, potassium testing can prove useful to assess levels and formulate dietary and possibly supplement recommendations.