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Potassium (K)
What is it?
Potassium is a trace mineral essential for growth and good health.
What does it do?
Potassium in the human body helps to:
- keep normal water balance between the cells and body fluids
- maintain normal blood pressure
- transmit nerve impulses
- enable the contraction of muscles
- ensure proper functioning of cellular enzymes
Where do you get it?
Potassium is found in a variety of types of foods, including fruits and vegetables, dairy products, meat and legumes.
Potassium Content of Foods
|
Very Good Sources |
About 400 milligrams or more |
|
Banana |
1 medium banana |
|
Cantaloupe |
8 oz. (1 cup) |
|
Orange juice |
8 oz. (1 cup) |
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Baked potato |
1 medium potato |
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Tomato juice |
8 oz. (1 cup) |
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Honeydew melon |
8 oz. (1 cup) |
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Nectarine |
1 large nectarine |
|
Dates |
4 oz. (1/2 cup) |
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Dried beans |
8 oz. (1 cup) cooked |
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Winter squash |
4 oz. (1/2 cup) cooked |
|
Good Sources |
Approximately 200-400 milligrams |
|
Collard greens |
4 oz. (1/2 cup) |
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Milk |
8 oz. (1 cup) |
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Spinach |
4 oz. (1/2 cup), frozen or boiled |
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Broccoli |
4 oz. (1/2 cup) |
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Raw tomato |
1 medium tomato |
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Cooked tomatoes |
4 oz. (1/2 cup) |
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Avocado |
1/2 avocado |
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Prunes |
4 prunes |
By eating five to nine servings of fruits and vegetables per day, you can get enough potassium to help lower your blood pressure and decrease your risk of cancer.
How much do we need?
There is no Recommended Dietary Allowance (RDA) for potassium. The minimum amount per day for adults is 2,000 milligrams, although many experts advise that a better minimum level would be around 3,500 milligrams. A low intake is defined as about 2,500 milligrams a day or less, while 4,000 to 4,500 milligrams a day is considered to be high. The typical U.S. diet provides about 2,000 to 3,000 milligrams a day.
Deficiencies of potassium are rare, but they can occur under the following conditions:
- starvation dieting
- prolonged vomiting or diarrhea
- laxative abuse
- severe burns
- kidney problems
Supplementary potassium may be recommended in certain cases:
- If a potassium deficiency occurs due to increased urinary losses (which are often associated with medications for high blood pressure), a supplemental amount of about 2,000 milligrams a day may be recommended.
- For certain medical conditions, medically supervised use of light salt or salt substitute as a source of potassium may be recommended. One teaspoon of light salt contains 1,500 milligrams of potassium, while salt substitute contains about 2,800 milligrams a teaspoon. For someone without kidney problems, however, fruits and vegetables are far better choices to boost potassium intake.
Potassium in amounts of around 2,300 milligrams a day -- whether from food or supplements -- has been shown to lower blood pressure by relaxing the arteries and reducing blood volumes, especially for people who use a lot of salt. In fact, this amount of potassium lowers blood pressure about half as much as drugs, without the expense or side effects. Potassium is especially effective in diets that also include generous servings of dairy products. The recent DASH (Dietary Approaches to Stop Hypertension) diet recommended 4,700 milligrams of potassium a day.
Is it safe?
Daily consumption of 2,000 to 6,000 milligrams of potassium is a safe range for the general population.
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