13.4: Potassium

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Potassium is the major intracellular cation. Good sources of potassium include beans, potatoes (with skin), milk products, orange juice, tomato juice, and bananas1 ,2. Potassium, like sodium and chloride, is well absorbed. Greater than 85% of consumed potassium is absorbed. Potassium is primarily excreted in urine (~90%)3. As you will learn in a later section, this is an electrolyte that we should try to consume more of rather than limiting like sodium and chloride.

One way to increase intake is through potassium chloride salt, which is an alternative to sodium chloride salt as described in the article below that FDA is proposing changing its name.

Web Link

FDA proposes changing name of healthier alternative to sodium

Potassium is important for:

Fluid Balance
Nerve transmission and muscle contraction

Increased potassium intake results in decreased calcium excretion. This is the opposite effect of increased sodium intake, which increases calcium excretion1.

Potassium deficiency is rare but can be fatal. Symptoms include:

Weakness
Fatigue
Constipation
slow reflexes
Irregular heartbeat (can be fatal)

Deficiency can occur in individuals that are on diuretics, drugs that increase urine production, and individuals with eating disorders1.

Toxicity is also extremely rare, only occurring if there is a problem with kidney function that prevents it from being excreted normally. Symptoms of toxicity are irregular heartbeat and even cardiac arrest (likely need to be potassium provided into circulation rather than consumed in some way)1.

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References

Byrd-Bredbenner C, Moe G, Beshgetoor D, Berning J. (2009) Wardlaw's perspectives in nutrition. New York, NY: McGraw-Hill.
Whitney E, Rolfes SR. (2011) Understanding nutrition. Belmont, CA: Wadsworth Cengage Learning.
Gropper SS, Smith JL, Groff JL. (2008) Advanced nutrition and human metabolism. Belmont, CA: Wadsworth Publishing.