Potassium is an essential mineral that performs many important functions in the body. Along with other electrolytes, potassium is necessary to maintain fluid balance, which is one of the pillars of our health. It is essential for muscle contractions and proper functioning of the nervous system alike, and higher intakes can reduce blood pressure and the risk of many diseases. (1) It is a hallmark of our modern diets that processed foods provide us with much more sodium (salt) than we need, but less potassium, which is found in higher amounts in fresh, natural foods. (2) Increasing potassium intake could be an important strategy to return to a healthy diet closer to our evolutionary patterns. Potassium is only available as a supplement in small doses due to regulations, as it can be dangerous to use with certain medications and diseases. Many people are afraid of potassium because of this, even though it is not at all dangerous for healthy individuals and most people could improve their health by increasing their intake of potassium.  

How much potassium do we need? 

The daily recommended intake of potassium has been set by various organizations at 2600-3500 mg for adults, while children need less, proportionate to their body weight. (3,4) In the past, 4700 mg per day was recommended for adults, but most people consume much less than even today's reduced recommendation: less than 3% of people reached the recommended daily intake of potassium in a 2011-12 US survey. (5) 

How to secure the necessary amount? 

The best sources of potassium are natural plant foods such as potatoes, pulses, vegetables, and fruits. Foods of animal origin, such as various meats, fish, or dairy products, also contain potassium, but usually less than plant foods. (3)  

To meet your potassium needs, it is important to eat natural foods that are as unprocessed as possible. In particular, foods made from refined grains and sugars should be replaced with potatoes, vegetables, and fruits. 

Because potassium supplements can only contain 100 mg of potassium per serving due to different regulations, it is not practical to meet our daily needs with them. Salts containing potassium, however, can be useful.    

Why is potassium so important? 

Blood pressure 

Higher intakes of potassium are protective against many diseases. One of its most important properties is that it can significantly reduce blood pressure, especially in the case of hypertension. People with higher dietary intakes of potassium have lower blood pressure, and a popular diet has been developed to take account of this. This is the DASH diet, which has been developed specifically to prevent high blood pressure and also results in a significant reduction in blood pressure. (6,7) An important aspect of the diet is that it contains three times as much potassium as the traditional Western-style diet on account of the copious amounts of fresh vegetables, fruits, and plant foods. 

Of course, these foods also contain many other beneficial substances, such as magnesium, but potassium supplementation on its own has been shown to be effective; several meta-analyses have found that it leads to significant reductions in blood pressure, especially in people with hypertension. Interestingly, replacing conventional table salt with a salt that also contains potassium can in itself lead to a significant reduction in blood pressure. (8,9,10) A study published in 2020 suggests that this strategy could also significantly reduce the risk of hypertension-related stroke, which could prolong the lives of millions of people worldwide. (11) 

Controlling blood sugar levels 

Higher intakes of potassium may also improve blood sugar control, as potassium 

 is needed for insulin production. (12) In an observational study, those with low potassium intake had more than twice the risk of developing type 2 diabetes compared to those with high potassium intake. (13) However, this is probably not solely due to potassium, as those who consume more potassium tend to consume more magnesium and other components that are useful for blood glucose control.  

Bone health 

A lesser-known property of potassium is that it can help keep bones strong, preventing osteoporosis in old age. One hypothesis suggests that one of the causes of osteoporosis may be eating too much acidic food, especially if one does not accompany it with enough alkaline foods or minerals in compensation. (14) Our bodies control the pH of our blood and other tissues quite well, but if one eats a diet rich in meat and grains with minimal vegetables, fruit, dairy, and minerals, they may be forced to use the calcium from their bones to control the pH. This theory is supported by the fact that potassium supplementation has improved bone density in some studies, as has the consumption of foods rich in potassium and magnesium. (15,16,17) 

Kidney stones 

Higher potassium intake also significantly reduces the risk of kidney stones. This is probably because potassium deficiency renders the kidneys unable to reabsorb calcium properly, increasing its excretion. In observational studies, the incidence of kidney stones was 35% lower in people with higher potassium intakes. (18)  

Can it be dangerous? 

Despite many misconceptions, it can be said that potassium consumption is not dangerous for healthy people because the excess is easily filtered out by the kidneys. (19) Most people's problem is rather that they do not consume enough. Potassium supplements aren't the devil's work, either: the use of the potassium-containing salts as mentioned above, or even potassium citrate supplements, may be beneficial for people who do not eat enough potassium-rich foods.  

Indeed, potassium consumption can be dangerous if you suffer from certain health problems or are taking specific medication, as these may prevent the excess from being excreted. Kidney failure, use of certain diuretics, and cardiac drugs can lead to an excess even at normal intake levels, while other diuretic drugs can easily cause potassium deficiency. In these cases, close medical supervision is always important. (19) 

Interesting facts 

Pure potassium is a very reactive substance. In contact with water, for example, it immediately starts to burn with a purple flame. It is no accident that it is found in nature only in combination with other substances. Bananas are renowned as the best source of potassium, but potatoes contain even more potassium than bananas: 2-3 medium-sized potatoes a day provide enough potassium for an adult.  

[The cover photo of the note shows bananas. 100 grams contain 358 mg of potassium, which provides one-tenth of the daily requirement.]