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Publication #FCS8805

Facts about Potassium1

R. Elaine Turner and Linda B. Bobroff2

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Why do we need potassium?

Potassium is a mineral found inside body cells. It is one of several minerals known as electrolytes. These minerals (potassium, sodium, and chloride) are found in the fluids inside and outside of body cells.

Potassium is important because it helps:

  • regulate fluid and electrolyte balance

  • maintain normal blood pressure

  • transmit nerve impulses

  • control muscle contraction, including the heart

  • maintain healthy bones.

What happens if we don't get enough potassium?

Potassium deficiency is rare. People with kidney problems, excessive diarrhea or vomiting, and those who use laxatives could have low potassium levels. Symptoms of low potassium in the body include weakness, poor appetite, nausea, and fatigue. Low potassium intake has been linked to hypertension and osteoporosis.

How much potassium do we need?

The following table lists recommended daily intakes of potassium.

Table 1. 

Life Stage

Potassium (mg/day)*

Men, ages 19+


Women, ages, 19+






*mg = milligrams

What does potassium have to do with high blood pressure?

Studies show that eating the recommended level of potassium can help maintain normal blood pressure. The best results occur when sodium intake is kept low.

Eating enough potassium can also reduce risk for stroke, and may reduce bone loss. A potassium-rich diet also can reduce the risk for kidney stones.

How can we get enough potassium?

Potassium is readily available in our food supply, especially in unprocessed foods.

Fruits and vegetables are the best dietary sources. Legumes (dried or canned) such as kidney, pinto, black, or red beans and lentils, are all good sources of potassium, as are peas, nuts, and seeds.

Here are some foods and the amount of potassium they contain:

Table 2. 


Potassium (mg/serving)*

Potato, baked with skin, 1 medium


Spinach, cooked, 1 cup


Pinto beans, cooked, 1 cup


Plantain, cooked, 1 cup


Prunes, dried, 10


Banana, 1 large


Orange juice, 1 cup


Cantaloupe, pieces, 1 cup


Lowfat (1%) milk, 1 cup


Papaya, pieces, 1 cup


Tuna (canned, in water), 3 ounces


Apple, with skin, 1 medium


Hummus, 1/3 cup


Walnuts, halves, ¼ cup


*mg = milligram

What about supplements?

Because potassium is widely available in foods, supplements aren't usually needed. Some people who take diuretic medication for blood pressure control may need to get more potassium but this is not true for all types of diuretics. Check with your doctor before taking a potassium supplement or using a salt substitute that contains potassium chloride.

How much is too much?

People who take diuretic medications or who have kidney disease should check with their doctor about proper potassium intake. Consuming more than five times the suggested amount of potassium can lead to hyperkalemia—high levels of potassium in the blood. Hyperkalemia can cause a heart attack and be fatal.

Where can I get more information?

The Family and Consumer Sciences (FCS) agent at your county Extension office may have more written information and nutrition classes for you to attend. Also, a registered dietitian (RD) can provide reliable information to you.

Reliable nutrition information may be found on the Internet at the following sites:



This document is FCS8805, one of a series of the Department of Family, Youth, and Community Sciences, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. First published: November 2006. Revised: March 2010. Please visit the EDIS website at


R. Elaine Turner, PhD, RD, associate dean, College of Agricultural and Life Sciences, and Linda B. Bobroff, professor, Department of Family, Youth, and Community Sciences, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611.

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.