Bananas are a common food many people don’t think about before eating.
But if you are taking losartan medication and have kidney problems, foods that are high in potassium, including bananas, may be unsafe.
In this article, we’ll discuss how losartan works, why potassium may be a problem for some people on losartan medication, and how to make sure you stay safe.
What is Losartan?
Losartan is an angiotensin II receptor blocker (ARB), a common class of drugs used for hypertension.
This class of medications is sometimes prescribed to people with high blood pressure who are also at risk of kidney problems.
High blood pressure affects 116 million Americans, and only 25% have it well-controlled.
When blood pressure problems are not properly managed, it can result in some serious health consequences, like:
- Loss of vision
- Heart disease, heart attack, or heart failure
- Kidney failure and other kidney problems
Blood pressure can be well-managed with medications, physical activity, and a healthy diet.
Losartan, for some, is an essential part of that blood pressure management plan.
Losartan is also approved by the U.S. Food and Drug Administration (FDA) for the treatment of:
- Diabetic nephropathy (kidney damage from type 2 diabetes)
- Kidney protection in people who have type 2 diabetes
How does losartan work?
Angiotensin II receptor blockers (ARBs) like losartan work by blocking the binding of angiotensin II, a hormone, with its receptors.
Angiotensin II works to constrict blood vessels, increasing blood pressure levels.
When the activity of angiotensin II is blocked, blood vessels remain relaxed, which keeps blood pressure lower.
When the blood vessels are more dilated, the heart does not have to work as hard to pump blood throughout the body, resulting in lower overall blood pressure.
Losartan and ARBs also increase the body’s urine output. This leads to less water retention and sodium.
When body fluids are lower, the heart does not have to work quite as hard, which can also decrease blood pressure.
This mechanism also protects the kidneys in people with diabetes.
Losartan starts working within 6 hours of taking it.
Should You Avoid Bananas While Taking Losartan?
Losartan and other medications may have side effects that lead to higher levels of potassium in the body.
Potassium is a mineral electrolyte that is necessary for proper fluid balance. But if you end up with too much or too little, it can lead to serious problems.
Because losartan helps remove extra fluids from the body, potassium levels can become higher.
This may not be a problem for someone with healthy kidneys or who eats a low potassium diet.
For people with kidney complications from type 2 diabetes, or at high risk for developing them, it is important to follow your medical provider’s instructions about maintaining low potassium, heart healthy, and kidney healthy diet.
What the research says
Whether or not you need to follow a low-potassium diet that would limit bananas and other potassium-rich foods depends on how healthy your kidneys are, your medical history, and what other medications and supplements you take.
Discuss your medications and other risk factors with your doctor.
Patients who already have kidney problems, such as chronic kidney disease or type 2 diabetes, are at higher risk for developing high potassium levels.
This is known as hyperkalemia.
Symptoms can range from mild to severe. In extreme cases, hyperkalemia can be fatal.
Certain medications can increase the risk for hyperkalemia when you take losartan:
- Potassium-sparing diuretics
- NSAIDs (nonsteroidal anti-inflammatory drugs) like ibuprofen, aspirin, and naproxen
The research on how significantly high-potassium foods influence the risk of hyperkalemia is not definitive.
Overall, it depends on how much dietary potassium you consume, along with any potassium you get from dietary supplements, including multivitamins.
Salt substitutes often contain potassium, too.
Patients who already have kidney-related risk factors may need to be careful if they are getting potassium from many sources or if they take multiple medications that help the body retain potassium.
According to the available research, most hyperkalemia cases occur in patients with kidney impairment.
They may take medication that retains potassium or get too much from dietary sources.
But hyperkalemia is extremely rare in patients with normal kidney function, even if they eat a diet that contains a lot of potassium.
In patients who have high blood pressure, but normal kidney function, losartan and a normal dietary intake of potassium are not likely to lead to hyperkalemia.
What is Hyperkalemia?
Hyperkalemia is the medical term for high levels of potassium in the blood.
Normal potassium levels are between 3.6 to 5.2 mmol/L. When the level goes above 5.2 mmol/L, it can indicate hyperkalemia.
Levels above 6.0 mmol/L may be life-threatening and require immediate medical treatment.
Who is at risk of hyperkalemia?
People who have the following conditions may be at higher risk of developing hyperkalemia:
- Acute kidney failure
- Chronic kidney disease (CKD)
- Type 2 diabetes with diabetic nephropathy
- Type 1 diabetes
- Addison’s disease
- Excessive use of potassium supplements
- Severe dehydration
- Red blood cell destruction from serious injury or burns
- Taking one or more medications that increase potassium in the body (angiotensin II receptor blockers, ACE inhibitors, beta-blockers, and potassium-sparing diuretics)
Symptoms of hyperkalemia
Symptoms of hyperkalemia can range from mild to severe:
- Tingling or numbness
- Decreased reflexes
- Muscle weakness
- Leg swelling
- Gas and bloating
- Lower heart rate
- Heart palpitations
- Generalized weakness
- Chest pain
- Trouble breathing
If you develop new symptoms for any reason, see a medical provider.
If you are at high risk for hyperkalemia based on your health history or medications and you notice new or worsening symptoms, get immediate medical help.
Dieting for Hyperkalemia
Most adults need between 3500-4500 mg of potassium each day.
If you are at risk for hyperkalemia, a healthcare provider will likely recommend a low-potassium diet.
This means keeping your intake around 2000 mg of potassium per day.
A diet for hyperkalemia mostly means avoiding foods high in potassium.
Foods to add
There are plenty of low-potassium foods that you can eat.
Some of these include:
- Chicken or turkey
- Green beans
- Bell peppers
- Apples and applesauce
- Cottage cheese and hard cheese
Foods to avoid
Foods that are high in potassium and may need to be limited or avoided include:
- Dried apricots
- Cooked lentils
- Acorn squash
- Baked potatoes
- Kidney beans
- Orange juice
- Salt substitutes
When to See a Medical Provider
If you have kidney problems and are not sure whether you should follow a low-potassium diet, ask a healthcare provider.
They can give you specific medical advice.
If you are being treated with losartan for high blood pressure or diabetes and are unsure about your potassium levels, ask a medical provider.
They may already know that your potassium levels are fine or can order a simple blood test to check.
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Frequently Asked Questions
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Adequate intake of potassium does not cause hyperkalemia in hypertensive individuals taking medications that antagonize the renin angiotensin aldosterone system. (2016).
Angiotensin II receptor blockers. (2022).
Cozaar (losartan potassium tablets). (2013).
Facts about hypertension. (2021).
Hyperkalemia: pathophysiology, risk factors, and consequences. (2019).