8 clues your body is low in potassium

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Qualified Nutritionist (BSc, MSc, RNutr)
Ask Emma

09 July 2019

How do you know if you are low in potassium?

Potassium is known as an electrolyte and it works in a delicate balance with other electrolytes to carry out important bodily functions, including managing fluid balance.

It is recommended that men get 3,400mg (3.4g) of potassium a day whilst women should aim for 2,600mg (2.6g). If we fail to get this recommended amount then a number of symptoms can arise, including:

  • Muscle weakness
  • Fatigue
  • Constipation
  • High blood pressure
  • Polyuria
  • Muscle paralysis
  • Breathing problems
  • Irregular heart beat

In this piece I will explain why these problems are linked to low potassium. Towards the end of the article I also include some advice on how to include more potassium in your diet, so read on to find out more about that as well.

1. Fatigue

Potassium is an essential nutrient that is present in all of the body's cells and tissues. The effects of low potassium levels can, therefore, extend to a wide range of bodily functions. One of the noticeable effects of this is low energy levels, which can be accompanied by physical and mental fatigue too.

2. Muscle weakness and cramp

One of potassium's key roles is muscle contraction - it helps to keep the skeletal muscles working optimally. In addition, it has a role in transmitting signals along the nerve fibres. If a potassium deficiency develops then general muscle weakness and cramping can also develop. This can affect the arms and legs, as well as other muscles in the body.

The problem can also be made worse if there is a magnesium deficiency. This mineral also plays an important role in muscle contraction so, if we don't get enough through our diet, cramps and spasms can worsen.

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3. Constipation and bloating

As well as influencing the skeletal muscles, potassium also ensures that the internal muscles that line the digestive tract are able to work properly. Low potassium can, therefore, affect the muscles in the intestines meaning food and waste pass through at a slower pace than usual. This may lead to uncomfortable symptoms such as bloating and constipation.

4. Muscle paralysis

As potassium is so important for the muscles, those with severe potassium deficiency (a problem known as hypokalaemia) can experience muscle paralysis.

Although this may be a more extreme symptom, muscle stiffness or limited movement are some warning signs to be aware of.

When potassium levels are very low, the muscles are unable to contract properly and in severe cases may eventually stop working altogether.

Hypokalaemia is a potentially life-threatening condition where potassium levels are less than 2.5millimoles per litre. This means any more extreme symptoms that could signify a severe potassium deficiency should be assessed by a doctor immediately.

5. High blood pressure

Another important role of potassium is to help keep the blood vessels relaxed. This helps to sustain low blood pressure. Should a deficiency in potassium develop, this could explain an increase in blood pressure.

This is particularly the case in people with high sodium or salt intake as this contributes to high blood pressure further. Interestingly, salt is found in excess in excess in processed foods, whilst quantities of potassium are limited. Instead it is more commonly found in fresh foods.

Potassium helps to balance sodium levels so doctors often recommend that people with high blood pressure lower their sodium intake and increase their potassium intake which can easily be achieved with some simple dietary changes. 

6. Polyuria

The kidneys are responsible for removing waste and regulating fluid levels. They also look after the balance of electrolytes such as sodium and potassium and regulate the body's acid/alkaline balance. In order to do this effectively, waste and excess electrolytes are passed out through urine.

A severe potassium deficiency can interfere with the kidney's ability to balance fluid and electrolytes. This can lead to frequent urination, a problem known as polyuria.

7. Breathing problems

Breathing problems are another serious side effect of hypokalaemia. This too can be linked to the fact that potassium has an essential role to play in muscle contraction, as breathing requires the use of several muscles, particularly the diaphragm.

If potassium levels become too low, the muscles aren't able to operate properly and shortness of breath or difficulty breathing may develop. If you notice any of these symptoms, you should always seek medical advice immediately.

8. Irregular heart beat

As well as working to keep the skeletal muscles functioning optimally, potassium is also important for keeping the heart muscles working.

Very low levels of potassium may, therefore, cause an irregular heart rhythm. This includes problems such as sinus bradycardia, ventricular tachycardia and ventricular fibrillation.

If treatment is not sought immediately, an irregular heartbeat can be life-threating so, in this instance, it is essential you seek medical attention straight away. Doctors can easily detect an irregular heart rhythm using an electrocardiogram and will also be able to check if your potassium levels are a possible cause.

What causes potassium deficiency?

Now that we've covered the symptoms of low potassium levels, you may be wondering what causes a deficiency in the first place.

High salt intake - Consuming too much salt often contributes to low potassium levels. If high concentrations of sodium flood into our body's cells, water follows it and potassium levels become low in contrast to these other elements. Our kidneys then have to work harder to regain water and maintain the electrolyte balance.

Illness - A stomach bug or a bout of diarrhoea can also lead to potassium deficiency. Prolonged vomiting or diarrhoea upsets the fluid balance in the body and also means that the body struggles to retain essential electrolytes and nutrients.

Medication – Some medications can increase the risk of deficiency. This includes diuretics, steroids, a high dose of insulin and certain antifungals. Some of these can cause the kidneys to excrete excess potassium, thus leading to hypokalaemia.

Excess sweating - Potassium can also be lost through sweat and so some of the problems listed above may develop during exercise or when an individual is in a hot climate.

Diet - Finally, simply failing to get enough potassium through your diet may also lead to the kind of symptoms I've just discussed, such as muscle cramps and fatigue. A reliance on pre-packed, processed foods rather than fresh goods can increase the likelihood of deficiency.

Sources of potassium

Potassium occurs naturally in a wide range of foods and is easily absorbed by the body. In order to increase your potassium intake, I would recommend including more of the following foods in your diet:

Food Quantity of potassium (per cup)
Dried apricots 2202mg
Dried prunes 1398mg
Cooked lentils 731mg
Cooked broccoli 458mg
Banana 422mg (in a medium sized banana)
Spinach 167mg
Cooked brown rice 154mg

Our Balance Mineral Drink is another good source of potassium and is particularly helpful if you are experiencing fatigue and muscle-related issues. Along with magnesium, zinc, calcium and vitamin D, Balance can help support normal muscle function and reduce the symptoms of tiredness and fatigue.

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Pour one sachet of Balance Mineral Drink into a glass containing 150ml of water or milk and then stir well. The drink has a natural strawberry flavour so is both refreshing and tasty!

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When to see your doctor

As explained above, hypokalaemia is a serious condition and so anyone with symptoms should see their doctor.

You should also visit your doctor if you experience these symptoms despite increasing your potassium intake.

A simple blood test will be able to determine whether or not low potassium levels are at the root of your symptoms. If you are on any medications, your doctor may also review these to determine if any could be causing issues.

Additional tests including a urine test can be recommended if the measures listed above prove inconclusive.

A.Vogel Balance Mineral Drink with Vitamin D3, Magnesium, Zinc, Potassium and Calcium.

7 x 5.5g sachets

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An instant strawberry-flavoured drink containing mineral salts, trace elements and l+ lactic acid …
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