Potassium is a key component in every living cell. It is found naturally in all plants and animals but is more common in plants, especially fruits and vegetables. It is most prevalent in orange juice, potatoes, bananas, tomatoes, avocados, cantaloupes and broccoli. Eating more fruits and vegetables has been shown to increase the potassium levels in humans.¹

The main function of potassium in the body is to keep fluids from becoming too concentrated or too dilute, a process known as osmo-regulation. The proper balance of potassium and sodium ions must be maintained in every cell. This balance is kept through the sodium-potassium pump system, which is the body’s way of keeping the appropriate ion concentration in each part of the body. This is the reason why potassium is a key component of sports drinks and recovery drinks. The electrolytes in the drinks help the body to maintain proper balance after exercise when sodium and potassium have been excreted through perspiration. For a similar reason, medications that contain potassium are used to lower blood pressure. They work because increasing potassium levels can decrease the sodium concentration in the blood, which leads to lower blood pressure levels.²

Potassium is best known as an electrolyte necessary for hydration, but like calcium and magnesium, it has a variety of roles in heart, muscle and kidney function. Potassium also functions to inhibit involuntary muscle contractions and is important for optimal brain and nerve function.

Correct levels of potassium in the body have also been linked to a reduced risk for cardiovascular disease.³ People who follow a diet comprised of high quantities of vegetables have been shown to have fewer heart attacks and strokes. A low potassium intake increases the chance of having a stroke or dying from cardiovascular disease.⁴

Studies have also linked potassium to increased bone strength and decreased risk of osteoporosis. One study showed a significant association between potassium intake and bone mineral density (BMD), which suggests that diets high in potassium will directly affect BMD, reducing the risk of developing osteoporosis.⁵

There also is a link between potassium intake and the ability of the pancreas to release insulin.⁶ A 1960s study showed this using patients who were at least 170% overweight. They were divided into two groups; one that was given potassium supplementation during a two week fast and another that was not given the supplement during the two week fast. The group receiving the potassium while fasting maintained a higher glucose tolerance, suggesting that the presence of potassium caused the pancreas to work more efficiently.⁷ This shows that from as early as the 1960s it was known that a healthy potassium intake can prevent diabetes.

As if its role in preventing high blood pressure, heart attacks, strokes, diabetes and osteoporosis isn’t enough, potassium can also prevent cancer. High dietary potassium is linked to a low risk of colorectal cancer.⁸ And that’s just what has been proven so far. It may prevent other types of cancer too. Let’s take a look at two more macrominerals and see what other shocking information is out there.

References

¹ Tuekpe MK, Todoriki H, Sasaki S, Zheng KC, Ariizumi M. Potassium excretion in healthy Japanese women was increased by a dietary intervention utilizing home-parcel delivery of Okinawan vegetables. Hypertens Res. 2006 Jun;29(6):389-96.

² Whelton PK, He J. Potassium in preventing and treating high blood pressure. Semin Nephrol. 1999 Sep;19(5):494-9.

³ Umesawa M, Iso H, Date C, Yamamoto A, Toyoshima H, Watanabe Y, Kikuchi S, Koizumi A, Kondo T, Inaba Y, Tanabe N, Tamakoshi A; JACC Study Group. Relations between dietary sodium and potassium intakes and mortality from cardiovascular disease: the Japan Collaborative Cohort Study for Evaluation of Cancer Risks. Am J Clin Nutr. 2008 Jul;88(1):195-202.

⁴ Iso H, Stampfer MJ, Manson JE, Rexrode K, Hennekens CH, Colditz GA, Speizer FE, Willett WC. Prospective study of calcium, potassium, and magnesium intake and risk of stroke in women. Stroke. 1999 Sep;30(9):1772-9.

⁵ Tucker KL, Hannan MT, Chen H, Cupples LA, Wilson PW, Kiel DP. Potassium, magnesium, and fruit and vegetable intakes are associated with greater bone mineral density in elderly men and women. Am J Clin Nutr. 1999 Apr;69(4):727-36.

⁶ Grodsky GM, Bennett LL. Cation requirements for insulin secretion in the isolated perfused pancreas. Diabetes. 1966 Dec;15(12):910-3.

7 Anderson JW, Herman RH, Newcomer KL. Improvement in glucose tolerance of fasting obese patients given oral potassium. Am J Clin Nutr. 1969 Dec;22(12):1589-96. 

⁸ Kune GA, Kune S, Watson LF. Dietary sodium and potassium intake and colorectal cancer risk. Nutr Cancer. 1989;12(4):351-9.

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