Deficiency in this key nutrient puts your overall health at risk

Humans have evolved to retain sodium and excrete potassium in response to diets that were low in sodium and high in potassium. Agriculture and industrialization, however, have led to big drops in the potassium available in foods, as well as increases in dietary sodium intake. Consequently, experts have labeled potassium a “nutrient of public health concern.”

Adequate intake of potassium

In 2019, a National Academies of Sciences, Engineering, and Medicine (NASEM) committee updated the daily recommended intakes for potassium. The committee found insufficient data to establish an estimated average requirement (EAR) for potassium, but they did recommend adequate intakes (AIs) for all ages derived from the highest median potassium intakes in healthy children and adults.

Age	Male	Female
Birth to 6 months	400 mg	400 mg
7–12 months	860 mg	860 mg
1–3 years	2,000 mg	2,000 mg
4–8 years	2,300 mg	2,300 mg
9–13 years	2,500 mg	2,300 mg
14–18 years	3,000 mg	2,300 mg
19–50 years	3,400 mg	2,600 mg
51+ years	3,400 mg	2,600 mg

Of note, EAR is defined as the intake estimated to meet the requirements of half of healthy individuals; and is used to plan nutritional diets for groups of people based on nutrient intakes. AI refers to the level of potassium needed to ensure nutritional adequacy; it is employed when evidence is insufficient to develop a recommended dietary allowance.

What are the dangers of low potassium?

The potassium ion (K+) is the primary intracellular cation, and plays an integral role in maintaining normal cell function, such as with the sodium-potassium pump. Additionally, intracellular K+ plays a principal role in acid–base regulation via extracellular hydrogen ions (H+) exchange and by affecting the rate of renal ammonium production.

In mild-to-moderate hypokalemia, muscular weakness, fatigue, and cramps are common. When the gut is involved, constipation or ileus may occur. Severe hypokalemia may result in flaccid paralysis, hyporeflexia, hypercapnia, tetany, and rhabdomyolysis.

The immediate dangers of hypokalemia are its effects on cardiac conduction and muscle strength. Indeed, in patients with cardiovascular disease, hypokalemia is associated with an increased risk of arrhythmia, all-cause mortality, cardiovascular mortality, and heart failure mortality. Very low potassium levels of less than 2.5 mmol/L can be life-threatening, and require urgent medical attention.

Potassium-rich foods

The body absorbs between 85% and 90% of dietary potassium. Potassium can be found bananas, cantaloupe, potatoes, broccoli, eggplant, zucchini, peas, cucumber, spinach, peas, and leafy greens, milk, coffee, tea, some meats, and yogurt. Potassium from fruits and vegetables takes the form of various compounds, including potassium phosphate, sulfate, and citrate. Potassium in food, however, does not take the form of potassium chloride, which can be found in potassium supplements.

Potassium in dietary supplements

In dietary supplements, potassium usually takes the form of potassium chloride, but potassium citrate, phosphate, aspartate, bicarbonate, and gluconate are also utilized. Importantly, the “Supplement Facts” panel on a dietary supplement label denotes the amount of elemental potassium present and not the weight of the compound used.

Although not all multivitamin supplements contain potassium, the ones that do typically offer about 80 mg of potassium. Moreover, supplements that contain only potassium are available and offer up to 99 mg of potassium.

A small number of studies have examined how the human body absorbs potassium derived from supplements. One study found that humans absorb about 94% of potassium gluconate in supplements, which is akin to the absorption rate from potatoes.

How many people are affected by low potassium levels?

In the community-dwelling population, mild hypokalemia is common—affecting almost 14% of outpatients. The prevalence is even higher among hospitalized patients, where as many as 20% are affected, with 4% to 5% being symptomatic.

Hypokalemia is defined as serum potassium concentrations below a normal range of 3.5–5.0 mEq/L. Severe/life-threatening hypokalemia occurs when potassium levels in the blood drop below 2.5 mEq/L.

In certain patient populations, the prevalence of hypokalemia is high. For instance, many patients with systemic diseases and about 80% of patients receiving diuretics may develop hypokalemia. Severe hypokalemia, however, is relatively uncommon. The prevalence of hypokalemia is the same in both men and women.

Benefits of potassium

According to the results of a meta-analysis involving 22 randomized-controlled trials, potassium intake decreased systolic blood pressure by 3.49 mm Hg and diastolic blood pressure by 1.96 mm Hg in adults, with hypertension. Furthermore, at higher levels of potassium intake, systolic blood pressure was reduced by 7.16 mm Hg. Increased potassium intake was also linked to a 24% lower risk of stroke. These findings suggest that increased potassium intake may serve as a preventive measure vs. hypertension and stroke.

The accompanying anions in dietary potassium compounds have been hypothesized to serve as an alkaline source that neutralizes acid load and decreasing calcium loss from the bone. Indeed, results of a Korean study involving 3135 men aged > 50 years and 4052 postmenopausal women demonstrated that the highest levels of dietary potassium intake were positively correlated with bone mineral density in both groups of participants. These results support the importance of potassium in bone health

On a final note, the effects of low potassium can last a lifetime, a fact which further bolsters the value of adequate potassium intake. Low potassium intake has been linked to chronic diseases including hypertension, cardiovascular disease, osteoporosis, and nephrolithiasis.