Potassium is one of the major minerals that you need to get from the foods you eat. It's an electrolyte, so it works with sodium and potassium to regulate your body's fluid levels. Getting a sufficient amount of potassium can blunt the impact of excessive sodium intake on blood pressure. It's also essential for bone health.
Potassium is found in a wide variety of foods -- especially foods of plant origin, including fruits, vegetables, legumes, mushrooms and nuts. Animal-based foods that contain potassium include unprocessed meat and dairy products. Some salt substitutes are made with potassium instead of sodium.
Even though potassium is abundant in whole foods, most people don't get enough. Probably because the average diet is low in fruits and vegetables and high in heavily processed foods that are low in potassium.
A full-blown potassium deficiency is as not common as dietary insufficiency and is usually due to excessive fluid loss from severe diarrhea, strenuous exercise, or use of diuretics.
The Institute of Medicine of the National Academies sets the dietary reference intakes (DRIs) for vitamins and minerals. The DRIs for potassium are based on age and women who are breastfeeding need a bit more. These DRIs are determined to be sufficient for a person of good health -- if you have any medical conditions, you should talk to your health care provider about your dietary needs, including potassium intake.
Dietary Reference Intakes (Adequate Intakes)
1 to 3 years: 3 grams per day
4 to 8 years: 3.8 grams per day
9 to 13 years: 4.5 grams per day
14+ years: 4.7 grams per day
Women who are pregnant: 4.7 grams per day
Women who are breastfeeding: 5.1 grams per day
The Institute of Medicine has not determined tolerable upper limits for potassium -- there aren't any reports of potassium toxicity from foods. But, it's possible to take too much potassium in the form of dietary supplements or salt substitutes. Excessive intake can result in hyperkalemia, which is a condition in which your blood has elevated levels of potassium.
Symptoms of hyperkalemia include muscle weakness, stomach pain, or irregular heartbeat -- and it can be life-threatening for people with kidney disease or diabetes.
The best way to ensure an adequate intake of potassium is to increase your consumption of potassium-rich foods. Potassium supplements can be dangerous for people with some medical conditions or who are taking certain medications. Always speak to your health care provider before taking dietary supplements.
Consuming potassium-rich foods may help reduce the risk of kidney stones, but people with kidney diseases may need to watch their potassium intake -- even from foods.
Learn More About Major Minerals
These are the minerals your body needs in larger amounts -- they're all essential for good health.
Colorado State University Extension. "Potassium and the diet." Accessed July 9, 2014. http://www.ext.colostate.edu/pubs/foodnut/09355.html.
Institute of Medicine of the National Academies. "Dietary Reference Intakes: Electrolytes and Water." Accessed July 9, 2014. http://www.iom.edu/~/media/Files/Activity%20Files/Nutrition/DRIs/DRI_Electrolytes_Water.pdf.
MedlinePlus Medical Encyclopedia. "Potassium in the diet." Accessed July 9, 2014. http://www.nlm.nih.gov/medlineplus/ency/article/002413.htm.
Otten JJ, Hellwig JP, Meyers LD. "Dietary Reference Intakes: The Essential Guide to Nutrient Requirements." Institute of Medicine, 2006.