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Publication #FCS8805

Facts about Potassium1

R. Elaine Turner and Linda B. Bobroff2

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 of body cells (intracellular) and outside the cells (extracellular).

Potassium is important because it helps:

• regulate fluid and electrolyte balance;

• maintain normal blood pressure;

• transmit nerve impulses;

• control muscle contraction, including the heart; and

• maintain healthy bones.

Figure 1. 

Legumes are excellent sources of potassium. Whether you start with the dried form or use convenient canned beans (low sodium is best), you will get a rich source of potassium.


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What happens if we don't get enough potassium?

Potassium deficiency is rare. People with kidney problems, excessive diarrhea, or vomiting, and those who regularly 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 (high blood pressure) and osteoporosis.

How much potassium do we need?

The following table lists daily intake levels of potassium that are expected to be adequate for children and have positive effects on blood pressure and possibly decrease bone loss in adults.

Table 1. 

Recommended daily intakes of potassium (adequate intake)

Life Stage

Potassium (mg/day)*

Children, ages 1–3 years

3,100

Children, ages 4–8 years

3,800

Children, ages 9–13 years

4,500

Youth, ages 14–18 years

4,700

Adults, ages, 19+

4,700

Pregnancy

4,700

Breastfeeding

5,100

*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 (less than 1,500 mg/day for adults at high risk for hypertension).

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

How can we get enough potassium?

Potassium is readily available in our food supply.

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 nuts and seeds.

The following table provides potassium values for several foods that are good to excellent sources of this mineral.

Table 2. 

Food Sources of Potassium.

Food

Potassium (mg/serving)*

Potato, baked with skin, 1 medium

950

Plantain, cooked, mashed, 1 cup

930

Pinto beans, cooked, 1 cup

750

Prunes, dried, 10

700

Orange juice, 1 cup

500

Banana, 1 large

490

Cantaloupe, cubes, 1 cup

430

Spinach, cooked, ½ cup

420

Low-fat (1%) milk, 1 cup

365

Papaya, pieces, 1 cup

265

Apple, with skin, 1 medium

195

Hummus, ⅓ cup

185

Tuna, light (canned, in water), 3 ounces

175

Walnuts, English, halves, ¼ cup

110

*mg = milligrams

Source: USDA National Nutrient Database for Standard Reference (http://ndb.nal.usda.gov/ndb/foods [accessed June 24, 2014])

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 death.

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:

http://solutionsforyourlife.ufl.edu

http://www.nutrition.gov

http://www.nlm.nih.gov/medlineplus/ency/article/002413.htm

http://healthyeating.nhlbi.nih.gov/ (heart-healthy recipes from NIH)

Footnotes

1.

This document is FCS8805, one of a series of the Department of Family, Youth, and Community Sciences, UF/IFAS Extension. Original publication date December 2006. Revised September 2014. Visit the EDIS website at http://edis.ifas.ufl.edu.

2.

R. Elaine Turner, PhD, RD, dean, College of Agricultural and Life Sciences; and Linda B. Bobroff, professor, Department of Family, Youth, and Community Sciences; UF/IFAS Extension, 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.