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Ernährungspotassium

In dieser Serie:Kaliumsparende Diuretika

Potassium is a mineral found naturally in many foods. It is needed in the body for the normal functioning of the heart, nerves and muscles. High potassium levels can lead to dangerous heart rhythms. Low potassium levels can cause muscle weakness and problems with the heart rhythm too. Long-term low levels of potassium has been linked to Bluthochdruck, Herzerkrankungen, and Schlaganfall. Low potassium is particularly likely to raise your blood pressure if you have a high intake of salt (sodium chloride).

Potassium relaxes the walls of the blood vessels, lowering blood pressure. It also protects against muscle cramping.

At a glance

  • Potassium is a mineral found in many foods, especially fruit and vegetables.

  • Low potassium can be caused by fluid loss, some medicines, and eating too much liquorice.

  • Symptoms of low potassium include tiredness, feeling sick, and high blood pressure.

  • High potassium is often caused by kidney problems or certain medications, such as ACE inhibitors.

  • Adults should aim for at least 3510 mg of potassium daily.

  • If you have severe symptoms of high or low potassium, seek medical advice.

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What are normal levels of potassium?

What can cause low potassium levels?

Having low levels of potassium in the blood is known as Hypokaliämie. It can be caused by the following risk factors:

  • If you lose a lot of fluid in Durchfall and through being sick (Erbrechen).

  • With excessive sweating - for example, in very hot countries.

  • Wenn Sie anorexia nervosa (this is due to a combination of being sick and taking too many laxatives, resulting in loss of fluids).

  • After eating too much liquorice, or if high doses of liquorice-containing herbal medicines are taken.

  • As a side-effect of medication, especially 'water' tablets (diuretics). This is the most common cause of low potassium.

A diuretic is a medicine which increases the amount of urine you pass out from your kidneys. There are different types of diuretic tablets and some, particularly loop diuretics and thiazide diuretics, can cause too much potassium to be lost with the extra urine passing out of the body. This can make the potassium levels very low, which can be quite dangerous. Kaliumsparende Diuretika can prevent this from happening.

What are the symptoms of low potassium?

Low levels of potassium can make you feel tired and sick (nauseous) and can cause high blood pressure. Very low levels can result in muscle weakness, swelling (Ödem) and dangerous heart rhythms.

What can cause high potassium levels?

High potassium in the blood is known as hyperkalaemia. It can be caused by the following risk factors:

If you need to follow a low-potassium diet because of kidney problems (such as kidney stones), you should be referred to a specialist dietician who will be able to advise you.

But for most people, eating potassium-rich foods is important to maintain a healthy diet. A reasonably high potassium intake helps to reduce blood pressure, which in turn reduces the risk of Schlaganfälle und Herzinfarkte.

The World Health Organization recommends that adults should eat at least 3510 mg of potassium daily. However, studies looking at potassium intake and stroke risk have found that very few people meet that target.

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Potassium is present in many different foods, particularly in fruit and vegetables. Therefore, making sure that you have at least five portions of fruit and vegetables daily is very important.

Processed foods tend to contain lower levels of potassium. For example, wholemeal bread and brown rice have higher levels or potassium than their white equivalents.

Salt substitutes, such as potassium chloride, are made from potassium, and using these instead of salt will increase your potassium intake. However, it is probably healthier to get used to food tasting less salty than to replace salt with this alternative.

Vegetables

Some vegetables which contain high levels of potassium are:

  • Medium baked potato (skin on) 925 mg.

  • Medium baked sweet potato (skin on) 450 mg.

  • Medium raw tomato 290 mg.

  • Half an avocado 490 mg.

Dark green leafy vegetables are also rich in potassium.

Fruits

Fruits which contain high levels of potassium include:

  • Medium banana 425 mg.

  • ¼ cup of raisins 270 mg.

  • Small orange 240 mg.

  • Medium pear 200 mg.

Other tropical fruits that are also rich in potassium include mango, papaya, kiwi and melon.

Proteins

Protein foods which contain high levels of potassium include:

  • Salmon (80 g portion) 534 mg.

  • ½ cup of lentils 365 mg.

  • Turkey (80 g portion) 250 mg.

  • 2 tablespoons of peanut butter 210 mg.

Other pulses and beans are also good sources of potassium.

Dairy

Dairy foods rich in potassium:

  • Small pot of yoghurt 350 mg.

  • 1 cup of milk 360 mg.

These are just examples of potassium-rich foods but most fresh foods contain quite high levels of potassium. So a normal healthy diet containing a variety of fruit and vegetables will provide enough potassium for most people. However, you should seek medical advice if you are experiencing severe symptoms from high or low potassium intake.

  • As a side-effect of medication, especially 'water' tablets (diuretics).

Häufig gestellte Fragen

What is the difference between different types of diuretics and their effect on potassium?

Diuretics are medications that increase the amount of urine your kidneys produce. Some types, specifically loop diuretics and thiazide diuretics, can lead to a significant loss of potassium in the urine, potentially causing very low potassium levels. However, other types called potassium-sparing diuretics are designed to prevent this potassium loss.

If I am on medication for high blood pressure, do I need to be careful about my potassium intake?

Some medications for high blood pressure, particularly ACE inhibitors, can cause high potassium levels. Additionally, 'water tablets' (diuretics), which are also used for high blood pressure, are a common cause of low potassium. If you are taking medication for high blood pressure, it's important to be aware of how these might affect your potassium levels.

Are there any risks associated with salt substitutes?

Salt substitutes, like potassium chloride, are made from potassium and can increase your potassium intake. While they can be used to replace salt, the article suggests it's generally healthier to get used to food tasting less salty rather than relying on these alternatives.

Can processed foods contribute to my daily potassium intake?

Processed foods generally contain lower levels of potassium compared to fresh, whole foods. For example, wholemeal bread and brown rice have higher potassium levels than their white equivalents. To ensure adequate potassium, focusing on fresh fruits and vegetables is more effective.

How can I tell if my potassium levels are too high or too low?

Low potassium levels can make you feel tired and nauseous and can lead to high blood pressure. Very low levels can cause muscle weakness, swelling, and dangerous heart rhythms. The article does not list specific symptoms for high potassium levels, but both conditions can be serious. If you experience severe symptoms, you should seek medical advice.

What role does potassium play in preventing serious health conditions?

A reasonably high intake of potassium is important for maintaining a healthy diet. It helps to reduce blood pressure, which in turn significantly lowers the risk of strokes and heart attacks.

Are there specific types of fruits and vegetables that are particularly good sources of potassium?

Yes, many fruits and vegetables are rich in potassium. Examples include baked potatoes and sweet potatoes (with skin), tomatoes, avocados, bananas, raisins, oranges, pears, mangoes, papayas, kiwis, and melons. Dark green leafy vegetables are also excellent sources.

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About the authorView full bio

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Dr Surangi Mendis, MRCGP

Consultant and Medical Author

MBBS, BSc (1st), MRCGP (2014), DFSRH, PGcert otology and audiology

Surangi Mendis is a consultant in Audiovestibular Medicine and Neuro-otology at The Royal National ENT and Eastman Dental Hospitals, UCLH.

About the reviewerView full bio

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Dr Hayley Willacy, FRCGP

Allgemeinmediziner, Medizinischer Autor

MBChB (1992), DRCOG, DFFP, MRCOG (Part 1) MRCGP (2007), DFSRH (2013), MSc - medical education (2020)

Dr Hayley Willacy was an NHS GP working in northwest England, who retired from clinical practice in 2022 after 30 years. 

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