What causes potassium deficiency and how to get enough potassium

Bananas aren’t the best source of potassium. Tetiana Tychynska/Shutterstock
  • Medications, like diuretics, and medical conditions, like vomiting and diarrhoea, are common causes of potassium deficiency.
  • A diet low in potassium and high in sodium can lead to an increased risk of heart disease, hypertension, and stroke.
  • It’s possible to get enough potassium by eating potassium-rich foods like kidney beans and dried apricots.
  • This article was medically reviewed by Samantha Cassetty, MS, RD, nutrition and wellness expert with a private practice based in New York City.
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Potassium is vital for long-term health. Multiple studies have shown that a diet high in potassium and low in sodium can reduce the risk of heart disease, hypertension, and stroke. For example, a 2016 meta-analysis of 16 studies found that consuming around 3500 mg a day correlated with the lowest risk of stroke.

On the flip side, if you have abnormally low levels of potassium in the blood – a condition called hypokalemia – you’re at an increased risk of these conditions and others. For example, low potassium can cause kidney stones because it impairs the kidney’s ability to reabsorb calcium, which can lead to a build-up that forms kidney stones.

Depending on how severe your potassium deficiency is, you may also suffer from symptoms like tiredness and fatigue, achy or weak muscles, constipation, and in more severe cases, cardiac arrhythmias, according to Mayo Clinic.

For the average healthy person, severe potassium deficiencies are rare. However, it’s important to get enough potassium in your diet. Here’s what you need to know about what can cause potassium deficiency and how to prevent it.

How much potassium you need each day

This chart, from the National Institutes of Health, shows how much potassium you should be getting based on your age and sex:

AgeMaleFemalePregnantLactatingBirth to 6 months 400 mg 400 mg 7-12 months 860 mg 860 mg 1-3 years 2,000 mg 2,000 mg 4-8 years 2,300 mg 2,300 mg 9-13 years 2,500 mg 2,300 mg 14-18 years 3,000 mg 2,300 mg 2,600 mg 2,500 mg 19-50 years 3,400 mg 2,600 mg 2,900 mg 2,800 mg 51+ years 3,400 mg 2,600 mg

Some medications cause potassium deficiency

You lose about 195 mg of potassium each day through urine, which is why medications that may cause you to lose more fluids – like diuretics, corticosteroids, laxatives, and enemas – are some of the most common causes of potassium deficiencies.

“Diuretics affect the part of the kidney that increase sodium levels in the distal tubules where urine is excreted,” says Laurena Law, MD. “This stimulates a sodium pump to reabsorb sodium in exchange for potassium resulting in increased loss of potassium from the blood.” So, you end up losing more potassium in your urine, than you otherwise would.

Law notes that antacids, aspirin, some antibiotics, and gout medicines can also cause potassium deficiency, as well as some supplements such as licorice. If you’re on any of these medications or supplements and suspect you’re suffering from symptoms of potassium deficiency, it may be time to consult a doctor who can give you advice on how to increase potassium in your diet.

Americans don’t consume enough potassium

Potassium is found predominantly in fruits and vegetables, so it’s perhaps unsurprising that most of us don’t get enough. In fact, only one in 10 Americans actually hits their recommended fruits and vegetable targets, according to the CDC. This can help explain why potassium deficiency was highlighted as a public health concern in the 2015-2020 Dietary Guidelines for Americans.

While the potassium-rich poster child, the banana, contains around 400 mg, there are other foods that pack a more potassium-rich punch including a cup of orange juice (496 mg), a cup of kidney beans (607 mg), the flesh of a medium baked potato (610 mg), and a half-cup of dried apricots (1,101 mg).

According to nutritionist Michelle Lau, founder and principal dietitian of Nutrilicious: “Consuming fresh fruits and vegetables such as bananas, prunes, oranges, strawberries, kiwi, avocados, apricots, leafy greens, mushrooms, peas, beets, and tomatoes, and as well as meat sources such as beef, fish, and turkey, can help meet the requirement.” Potassium is also a key part of the popular DASH (Dietary Approaches to Stop Hypertension) diet.

Medical conditions or operations can lead to potassium deficiency

Vomiting, diarrhoea, and other symptoms can cause the body to lose fluids and electrolytes, including potassium. If excessive or prolonged, this could lead to hypokalemia.

“Potassium deficiency is also present in some patients who have an ileostomy (stoma) or have had bowel surgery since stool excretion can contain significant amounts of potassium,” says Lau.

And sometimes it doesn’t matter how much potassium you consume, you may still be at risk of hypokalemia. This can happen in rare cases when you have kidney issues – like Fanconi Syndrome and Renal Tubular Acidosis – that impair your kidney’s ability to regulate potassium levels in the blood.

Potassium is also absorbed in the small intestine, so inflammatory bowel disease (IBD), including Crohn’s disease and ulcerative colitis, can cause potassium deficiency as IBD reduces electrolyte absorption and increases potassium secretion through diarrhoea.

If you think you may be at risk for low potassium, check with your doctor to determine the root of the problem and how to ensure you’re meeting your needs.