Potassium

What is potassium?

Potassium is a key mineral for the human body as it counteracts sodium in many physiological processes. High doses of dietary potassium are an effective approach towards reducing hypertension and related chronic heart diseases caused by high sodium intake. A relatively abundant mineral in food resources and in human diets, potassium is generally under consumed by most people due to their high sodium intake.

How do potassium and sodium interact with each other?

The absorption of potassium and sodium is controlled by the same molecule called the Na+/K+ channel that transports potassium and sodium in opposite directions. High sodium intake leads to loss of potassium through urine. Vice versa, high potassium intake leads to sodium excretion through urine.

How is potassium used in the human body?

Potassium functions as one of the major electrolytes (together with sodium, chloride and magnesium) that conducts electricity in the human body. In addition, it plays important roles in maintaining the balance of fluids in the body, nerve impulse transmission and muscle contraction. 

What is the body’s normal potassium level?

The normal potassium level in the human body is 3.5-5.0 mEq/L (136.5-195 μg/ml). Anything lower than 3.5 mEq/L is called hypokalemia which can cause a lack of energy, muscle cramps, stomach disturbances, and irregular heartbeat. Anything over 5 mEq/L can lead to hyperkalemia, a common condition diagnosed in up to 8% of hospitalized patients in the United States and could lead to cardiac arrest and death in severe cases.

Neither hypokalemia nor hyperkalemia has dietary causes.  They are often the result of other underlying diseases (such as kidney failure) or reactions to certain medicines (such as ACE inhibitors).

How much potassium do I need in my diet?

The Institute of Medicine of the National Academies recommends an intake of 4,700mg of potassium (approximately 6-7 small potatoes worth) for the average adult. Currently, few Americans consume an adequate amount of potassium. In fact, the typical American consumes only 56% this amount. Therefore, most of us need to increase our intake of dietary potassium. For individuals with kidney disease and those who take certain medications, specific guidance for potassium intake from their health care provider is advised.

Is it possible to consume too much potassium from diet?

Diet alone cannot lead to overconsumption of potassium.  If you are diagnosed with hyperkalemia, it could be the result of another disease, a medication, or simply too much supplemented potassium. Seek your health care provider’s advice regarding hyperkalemia.

Should I take potassium supplements?

You should not take potassium supplements unless you are advised to by your doctor. Potassium supplements may not be safe for people with certain diseases and overdoses can cause confusion, tingling sensations in the limbs, low blood pressure, irregular heartbeat, weakness, and comas.

Why is eating sufficient potassium more important for people carrying certain gene variants?

People with certain genetic variants, including a genetic variant of the ACE gene and three genetic variants of the NOS3 gene, are more sensitive to sodium levels. Increasing potassium while limiting sodium is a more effective method to prevent hypertension and related cardiovascular diseases than limiting sodium alone for carriers of these variants.  Over 50% of Africans and Caucasians and about 40% of Asians carry the ACE gene variant. People carrying one of the three NOS3 gene variants range in frequency from 20% to 50% in different ethnic populations.

Which foods contain high levels of potassium?

Dietary potassium is found in all food groups, but vegetables, fruits, milk, and fish are generally considered potassium-rich foods. (Table 1).

Table 1. Common potassium-rich foods.

Tomato, paste Per 100 g (mg) 1014 Per Serving (mg) 664 Serving Size 1/4 cup (65.5 g)	Tomato, puree Per 100 g (mg) 370-760 Per Serving (mg) 370-650 Serving Size 1 cup	Beans Beans, Lima beans Per 100 g (mg) 460-620 Per Serving (mg) 360-480 Serving Size 1/2 cup
Meats Beef, round Per 100 g (mg) 430-440 Per Serving (mg) 360-370 Serving Size 3 oz (85 g)	Pork, loin Per 100 g (mg) 430-440 Per Serving (mg) 360-370 Serving Size 3 oz (85 g)	Fish, cod Per 100 g (mg) 450-620 Per Serving (mg) 380-530 Serving Size 3 oz (85 g)
Fish, halibut Per 100 g (mg) 450-620 Per Serving (mg) 380-530 Serving Size 3 oz (85 g)	Vegetables Potato, baked Per 100 g (mg) 400-540 Per Serving (mg) 550-740 Serving Size 1 small-medium (138 g)	String Beans Per 100 g (mg) 370-760 Per Serving (mg) 370-650 Serving Size 1 cup
Squash, winter Per 100 g (mg) 370-760 Per Serving (mg) 370-650 Serving Size 1 cup	Spinach Per 100 g (mg) 370-760 Per Serving (mg) 370-650 Serving Size 1 cup	Beet green Per 100 g (mg) 370-760 Per Serving (mg) 370-650 Serving Size 1 cup
Fruits Honeydew Per 100 g (mg) 230-270 Per Serving (mg) 360-420 Serving Size 1 cup (156 g)	Cantaloupe Per 100 g (mg) 230-270 Per Serving (mg) 360-420 Serving Size 1 cup (156 g)	Bananas Per 100 g (mg) 230-270 Per Serving (mg) 360-420 Serving Size 1 cup (156 g)
Juices Juice, carrot Per 100 g (mg) 200-270 Per Serving (mg) 500-700 Serving Size 1 cup (256 g)	Juice, orange Per 100 g (mg) 200-270 Per Serving (mg) 500-700 Serving Size 1 cup (256 g)	Milk Milk Per 100 g (mg) 150-160 Per Serving (mg) 370-380 Serving Size 1 cup (245 g)

How do I ensure I am getting enough potassium in my diet?

We recommend the use the GB Food Calorie and Nutrition Calculator to get the most accurate estimate of your current potassium intake.

To increase potassium intake, eat potassium-rich foods such as those shown in table 1. Many canned foods (such as tomato paste) also contain very high levels of potassium.

Read the Nutrition Facts while grocery shopping to choose foods with high potassium content (250 mg or more per serving) and to avoid those with low potassium (150 mg or less per serving).

Meanwhile, due to the counteractions between potassium and sodium, limiting dietary sodium also helps retain potassium in your body.

Coffee and alcohol also deplete potassium in human body.  Avoiding excess consumption of these two drinks will also help maintain an appropriate potassium level.