How much do we need and how much are we getting?

The recommended daily value for potassium is 4,700 mg. Nearly all fresh fruits and vegetables are excellent sources of potassium, while nuts, seeds, legumes, and dairy products are the next highest sources. Yet, despite its wide abundance in food, most Americans don’t get enough. In fact, because of low intakes, the 2015-2020 Dietary Guidelines for Americans upgraded potassium to a “nutrient of public health concern,” as its underconsumption can lead to adverse health outcomes. In an effort to raise awareness of potassium intake, manufacturers must now display the amount of potassium in packaged foods on the Nutrition Facts label.

A severe deficiency of potassium is rarely due to insufficient intake alone, but usually a combination of insufficient intake and increased excretion due to things like anorexia nervosa, crash diets, alcoholism, conditions that cause intestinal malabsorption, excessive sweating, laxative abuse, use of diuretics, or prolonged diarrhea or vomiting.^{2 3}  You don’t have to have an outright deficiency to suffer the effects of inadequate potassium intake, though. Insufficiency of potassium may increase blood pressure, kidney stone risk, bone turnover, urinary calcium excretion, and salt sensitivity.⁴

Potassium’s Relationship to Sodium

Potassium and sodium have a strong relationship. As mentioned, they are both involved in cell signaling. They also work together to maintain and balance fluid distribution throughout the body. Our paleolithic ancestors ate a lot of potassium and not much sodium. Their sodium to potassium intake is estimated to have been somewhere between 1:5 and 1:10. Unfortunately, due to processed foods and a low fruit and vegetable intake, the average Western diet is the opposite: high in sodium but low in potassium, a ratio of 1:1 or worse.⁵  This chronic imbalance leads to many concerns and a chronic state of acidosis, which has its own health implications. While there is a lot of focus on reducing sodium intake, the sodium to potassium ratio might be even more important. In one study, people with the highest sodium to potassium ratio in their diets had significantly greater risk of cardiovascular disease and death from all causes.⁶ The bottom line is that we evolved to eat an abundance of potassium in relation to sodium and can’t achieve our best health when the ratio of sodium to potassium is imbalanced.

Potassium and Heart Health

Perhaps the most researched benefit of potassium is on heart health. High blood pressure (aka hypertension) is a major risk factor for heart disease and stroke and can also increase the risk of developing heart failure, kidney disease, pregnancy complications, and cognitive decline later in life.⁷ Higher levels of potassium intake are strongly associated with lowered blood pressure in those with hypertension but not in those with normal blood pressure, and the effects appear to be greatest in those on a high sodium diet.^{8 9 10} A higher potassium intake, and improved sodium to potassium ratio, also appears to protect children from rising blood pressure, both in childhood and into adulthood.^{11 12} There is also some evidence suggesting higher potassium may reduce the risk of stroke.^{13 14}

Potassium and Bone Health

The typical Western diet, high in refined sugars and grains and low in fruits and veggies, contributes to bone loss. Potassium from potassium-rich foods (but also supplements) may help to counter the negative effects this diet can have on the bones. Several studies have found an association between higher potassium levels and higher bone mineral density (a measure of the amount of minerals in the bones that is used to determine the strength of the bones).^{15 16}  Not many clinical trials have explored the effects of increasing potassium on bone outcomes and the results thus far have been mixed. However, there are some studies that have found an improvement in markers of bone mineral density and/or a decrease in calcium excretion when potassium supplements are added.^{17 18 19}

Potassium and Blood Sugar

Potassium is necessary for the secretion of insulin; without insulin cells can’t take in and use the sugar (aka glucose) from our diets, leading to elevated blood sugar levels. An association between lower potassium intake and an increased risk of developing type II diabetes or metabolic syndrome has been seen in large population studies.^{20 21} In the lab, inducing potassium deficiency in humans leads to a decrease in the amount of glucose they are able to metabolize.²² In one small study, African Americans with prediabetes were given 750 mg of potassium chloride twice a day for three months. Compared to baseline, potassium supplementation led to stable or improved fasting glucose, while those taking the placebo had increased fasting glucose.²³ 

Potassium and Kidney Stones

A higher potassium diet appears to be protective against the formation of kidney stones in the general population.²⁴ For those with a history of kidney stones, potassium citrate is often prescribed, although it appears to be most appropriate for those with calcium stones and low or relatively low urinary citrate levels, so working with a doctor is paramount.²⁵

How to Get Enough Potassium

The first step is to increase your dietary intake through whole, real foods, especially fresh fruits and vegetables. Not only will these foods supply lots of potassium, they should help to crowd out other less healthful foods that contain little to no potassium. You can also add a supplement to your routine. Potassium supplements are well absorbed and have very few side effects, with minor GI upset being the most common. Supplementation is safe for healthy people with normal kidney function, however, anyone with chronic kidney disease or anyone using angiotensin converting enzyme (ACE) inhibitors or potassium sparing diuretics should talk with their doctor before increasing potassium intakes.²⁶ It can be helpful to increase potassium through supplementation slowly to allow the body time to adjust.

Potassium in Food

While most all fresh fruits and vegetables and many whole, real foods are high in potassium, the list below includes some superstars.

Why 99mg?

Despite the importance of potassium and the high amounts needed for optimal function, potassium capsules and tablets are only available in 99 mg. This stems from a statement issued by the FDA in 1975 over concerns of small bowel lesions, related to drugs containing over 100 mg of potassium. The Council for Responsible Nutrition (CRN) has called for new clarification on this statement, pointing out that clinical trials using supplemental potassium and population research examining fruit and vegetable intake suggest potassium is exceptionally safe, even in higher quantities. The CRN suggests an upper limit for supplements of 1,500 mg per day divided into 500 mg doses.²⁷ Potassium supplements that will be diluted prior to ingestion (such as powders) are not limited to 99 mg and may be the most effective way to achieve meaningful potassium amounts.

References

1. Office of Dietary Supplements – Potassium. (2020, June 03). Retrieved July 07, 2020 from https://ods.od.nih.gov/factsheets/Potassium-HealthProfessional/
2. Palmer, B.F., Clegg, D.J. (2016). Physiology and pathophysiology of potassium homeostasis. Adv Physiol Educ, 40(4), 480-490. DOI: 10.1152/advan.00121.2016
3. Office of Dietary Supplements – Potassium. (2020, June 03). Retrieved July 07, 2020 from https://ods.od.nih.gov/factsheets/Potassium-HealthProfessional/
4. Office of Dietary Supplements – Potassium. (2020, June 03). Retrieved July 07, 2020 from https://ods.od.nih.gov/factsheets/Potassium-HealthProfessional/
5. Smith, M.J. (2020, Apr 23). The sodium/potassium ratio and its implications in human health. Thepaleodiet.com. Retrieved from: https://thepaleodiet.com/the-sodiumpotassium-ratio-and-its-importance-in-human-health/
6. Yang, Q., Lui, T., Kuklina, E.V., Flanders, D., Hong, Y., Gillespie, C., Change, M-H., Gwinn, M., Dowling, N., Khoury, M.J., Hu, F.B. (2011). Sodium and potassium intake and mortality among US adults: prospective data from the third National Health and Nutrition Examination survey. Arch Intern Med, 171(13), 1183-1191.   doi:10.1001/archinternmed.2011.257
7. Substance Abuse and Mental Health Services Administration (US); Office of the Surgeon General (US). The Surgeon General’s Call to Action to Control Hypertension [Internet]. Washington (DC): US Department of Health and Human Services; 2020. Available from: https://www.ncbi.nlm.nih.gov/books/NBK567645/
8. Filippini, T., Naska, A., Kasdagli, M. I., Torres, D., Lopes, C., Carvalho, C., Moreira, P., Malavolti, M., Orsini, N., Whelton, P. K., & Vinceti, M. (2020). Potassium Intake and Blood Pressure: A Dose-Response Meta-Analysis of Randomized Controlled Trials. Journal of the American Heart Association, 9(12), e015719. https://doi.org/10.1161/JAHA.119.015719
9. Aburto, N. J., Hanson, S., Gutierrez, H., Hooper, L., Elliott, P., & Cappuccio, F. P. (2013). Effect of increased potassium intake on cardiovascular risk factors and disease: systematic review and meta-analyses. BMJ (Clinical research ed.), 346, f1378. https://doi.org/10.1136/bmj.f1378
10. Mente, A., O'Donnell, M. J., Rangarajan, S., McQueen, M. J., Poirier, P., Wielgosz, A., Morrison, H., Li, W., Wang, X., Di, C., Mony, P., Devanath, A., Rosengren, A., Oguz, A., Zatonska, K., Yusufali, A. H., Lopez-Jaramillo, P., Avezum, A., Ismail, N., Lanas, F., … PURE Investigators (2014). Association of urinary sodium and potassium excretion with blood pressure. The New England journal of medicine, 371(7), 601–611. https://doi.org/10.1056/NEJMoa1311989
11. Geleijnse, J.M., Grobbee, D.E., Hofman, A. (1990). Sodium and potassium intake and blood pressure change in childhood. BMJ, 300(6729, 899-902.  doi: 10.1136/bmj.300.6729.899
12. Buendia, J. R., Bradlee, M. L., Daniels, S. R., Singer, M. R., & Moore, L. L. (2015). Longitudinal effects of dietary sodium and potassium on blood pressure in adolescent girls. JAMA pediatrics, 169(6), 560–568. https://doi.org/10.1001/jamapediatrics.2015.0411
13. Larsson, S. C., Orsini, N., & Wolk, A. (2011). Dietary potassium intake and risk of stroke: a dose-response meta-analysis of prospective studies. Stroke, 42(10), 2746–2750. https://doi.org/10.1161/STROKEAHA.111.622142
14. D’Elia, L., Barba, G., Cappuccio, F.P., Strazzullo, P. (2011). Potassium intake, stroke, and cardiovascular disease: a meta-analysis of prospective studies. J Am Col Cardiol, 57(10), 1210-1219.  https://doi.org/10.1016/j.jacc.2010.09.070
15. Kong, S. H., Kim, J. H., Hong, A. R., Lee, J. H., Kim, S. W., & Shin, C. S. (2017). Dietary potassium intake is beneficial to bone health in a low calcium intake population: the Korean National Health and Nutrition Examination Survey (KNHANES) (2008-2011). Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA, 28(5), 1577–1585. https://doi.org/10.1007/s00198-017-3908-4
16. Tucker, K. L., Hannan, M. T., Chen, H., Cupples, L. A., Wilson, P. W., & Kiel, D. P. (1999). Potassium, magnesium, and fruit and vegetable intakes are associated with greater bone mineral density in elderly men and women. The American journal of clinical nutrition, 69(4), 727–736. https://doi.org/10.1093/ajcn/69.4.727
17. Moseley, K. F., Weaver, C. M., Appel, L., Sebastian, A., & Sellmeyer, D. E. (2013). Potassium citrate supplementation results in sustained improvement in calcium balance in older men and women. Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research, 28(3), 497–504. https://doi.org/10.1002/jbmr.1764
18. Marangella, M., Di Stefano, M., Casalis, S., Berutti, S., D'Amelio, P., & Isaia, G. C. (2004). Effects of potassium citrate supplementation on bone metabolism. Calcified tissue international, 74(4), 330–335. https://doi.org/10.1007/s00223-003-0091-8
19. Sebastian, A., Harris, S. T., Ottaway, J. H., Todd, K. M., & Morris, R. C., Jr (1994). Improved mineral balance and skeletal metabolism in postmenopausal women treated with potassium bicarbonate. The New England journal of medicine, 330(25), 1776–1781. https://doi.org/10.1056/NEJM199406233302502
20. Colditz, G. A., Manson, J. E., Stampfer, M. J., Rosner, B., Willett, W. C., & Speizer, F. E. (1992). Diet and risk of clinical diabetes in women. The American journal of clinical nutrition, 55(5), 1018–1023. https://doi.org/10.1093/ajcn/55.5.1018
21. Shin, D., Joh, H. K., Kim, K. H., & Park, S. M. (2013). Benefits of potassium intake on metabolic syndrome: The fourth Korean National Health and Nutrition Examination Survey (KNHANES IV). Atherosclerosis, 230(1), 80–85. https://doi.org/10.1016/j.atherosclerosis.2013.06.025
22. Rowe, J.W., Tobin, J.D., Rosa, R.M., Andres, R. (1980). Effect of experimental potassium deficiency on glucose and insulin metabolism. Metabolism, 29(6),498-502. DOI:https://doi.org/10.1016/0026-0495(80)90074-8
23. Chatterjee, R., Slentz, C., Davenport, C. A., Johnson, J., Lin, P. H., Muehlbauer, M., D'Alessio, D., Svetkey, L. P., & Edelman, D. (2017). Effects of potassium supplements on glucose metabolism in African Americans with prediabetes: a pilot trial. The American journal of clinical nutrition, 106(6), 1431–1438. https://doi.org/10.3945/ajcn.117.161570
24. Ferraro, P.M., Mandel, E. I., Curhan, G.C., Gambaro, G., Taylor, E.N. (2016). Dietary protein and potassium, diet-dependent net acid load, and risk of incident kidney stones. Clin J Am Soc Nephrol, 11(10), 1834-1844.  doi: 10.2215/CJN.01520216
25. Suarez, M., Youssef, R.F. (2015. Potassium citrate: treatment and prevention of recurrent calcium nephrolithiasis. J Clin Neprhol Res, 2(1), 1015. Retrieved from: https://www.jscimedcentral.com/Nephrology/nephrology-2-1015.pdf  
26. Office of Dietary Supplements - Potassium. (2020, June 03). Retrieved July 07, 2020, from https://ods.od.nih.gov/factsheets/Potassium-HealthProfessional/
27. Hathcock, J.N., Griffiths, J.C. (2014). Vitamin and mineral safety (3^rd edition) (MacKay, D., Wong, A., Nguyen H., Eds). Council for Responsible Nutrition. Available at https://www.crnusa.org/resources/vitamin-mineral-safety