Potassium and Fluid Retention

Potassium is an essential mineral responsible for the proper function of cells, tissues, and organs in the body. It is an electrolyte that is required to maintain a normal water balance in the body. 

Is there a connection between potassium and fluid retention? Let’s find out. 

Lack of enough potassium can cause water retention, which leads to medical conditions such as edema, swelling, and weight gain. 

Potassium is among the 10 most common minerals in the body. It is essential for membrane polarization in the neurons of the nervous system and also for maintaining the osmotic balance between the cells and the interstitial fluids.

While sodium is mostly found in the plasma, potassium is mostly found in the cells. In size, it is a bigger ion than sodium and, therefore, must be pumped out of the cells when needed.

The interchange between sodium and potassium is mediated by the Na+/K+-ATPase pump. This ion pump creates an electrical gradient in cell membranes by pumping out 3 sodium ions out of the cells and 2 potassium ions into them.

The tongue can detect potassium ions. In fact, potassium triggers 3 out of the 5 taste sensations. Low concentrations of potassium salts taste sweet while high concentrations taste alkaline or bitter. Potassium can also taste salty.

The bitter taste of high concentration potassium salt solutions is the reason why they are rarely used in potassium supplementation therapies.

Potassium in the Body

Potassium is essential for muscle contraction and impulse conduction in the nerves. When the potassium level in the body falls, a medical condition known as hypokalemia results.

Symptoms of hypokalemia include vomiting, diarrhea, excessive diuresis, decreased contractility of the muscles, metabolic alkalosis, respiratory paralysis, and arrhythmia.

When the potassium level is too high, it can cause hyperkalemia. Hyperkalemia is just as dangerous as hypokalemia.

Symptoms of hyperkalemia include malaise, muscle weakness, metabolic acidosis, and palpitations. Others include tingling in the hands and feet and arrhythmia.

Unlike sodium which is mostly found in the blood plasma, potassium is the major positive ion in cells. Therefore, it is filtered to a lesser extent in the kidneys.

When the plasma passes through the kidneys, it is filtered by the glomerulus. Most of the sodium and potassium passing through are reabsorbed back into the blood.

As the plasma passes through the kidneys, potassium is secreted twice and reabsorbed three times along the way.

Even then some potassium is still lost to urine every day. Therefore, if equal amounts of potassium are not regained in diet, an electrolyte imbalance will result which could lead to hypokalemia.

Potassium for Fluid Retention 

Edema, also known as water retention, is swelling of the body. It is mainly caused by fluid retention in the spaces between the body's cells or in the circulatory system. 

Edema causes swelling and puffiness in the face, feet, ankles, and abdomen. It also causes sudden changes in mental state, shortness of breath, and muscle ache. According to Acu-Cell Nutrition, edema is also a symptom of potassium deficiency. 

Potassium supplements are sometimes prescribed for edema. You should consult with your doctor or health care practitioner before taking additional potassium for fluid retention, especially if you are taking diuretics.

Potassium and Diuretics

Diuretics are known to promote potassium loss in the kidneys. This is only an unfortunate side effect of flushing out sodium and water from the body.

There are 3 types of diuretics commonly used. These are loop diuretics, thiazide diuretics, and potassium-sparing diuretics. The first two types of diuretics promote potassium loss and can cause hypokalemia.

Loop and thiazide diuretics inhibit the sodium/potassium symporters responsible for reabsorbing sodium and potassium ions in the nephrons of the kidney.

By sharing the same transporter (a symporter is a transporter for multiple ions) with sodium, the reabsorption of potassium is also blocked. Loop diuretics inhibit these transporters at the ascending limb of the loop of Henle while thiazide diuretics do that at the distal convoluted tubules.

Since diuresis is a sign of hypokalemia and diuretics cause diuresis, it might be difficult to determine when hypokalemia results from the use of these diuretics. Therefore, potassium supplements are recommended to be taken alongside.

Lasix, a popular brand of Furosemide which is a loop diuretic, is sometimes combined with a potassium salt as Lasix K to prevent hypokalemia caused by the diuretic.

Potassium-sparing diuretics, on the other hand, do not cause potassium loss in the kidneys. Rather, they prevent the reabsorption of sodium and water by other means.

There are 2 main groups of potassium-sparing diuretics. One group is exemplified by spironolactone which blocks the effect of aldosterone.

Aldosterone is the corticosteroid hormone secreted by the adrenal gland in the last stage of the activation of the renin-angiotensin-aldosterone system. This system is one of the body’s mechanisms for promoting water retention.

The other group is represented by amiloride which blocks sodium pumps in the kidneys.

Because potassium-sparing diuretics spare potassium, they never cause hypokalemia. However, they might cause hyperkalemia, especially in patients already eating potassium-rich foods.

Other Health Conditions 

Low levels of potassium may also cause other health conditions such as weight gain, sweating, and muscle cramps. 

As potassium deficiency is caused due to water retention, it may cause weight gain. High levels of water retention are associated with weight gain. 

Too much sweating and exercise can cause a depletion of potassium, which may lead to edema or water retention. Many athletes use the sauna method to shed weight by excess sweating and exercise. 

Sitting in the sauna for longer hours may cause a reduction of potassium levels through sweating. The potassium is lost through the sweat glands. 

A study published in the "Journal of Applied Physiology" in December 1982 examined athletes during outdoor and indoor exercise; both in warm and cool climates. They also tested the athletes in the sauna and found that potassium is constantly lost in equal amounts in all types of climatic conditions. 

Muscle cramps are abrupt reflex spasms that cause the muscles to contract. They are quite painful but only last a few minutes. They usually occur after exercising or at night. 

According to the National Institutes of Health, muscle cramps may be caused due to a lack of water retention in the body. The loss of water also leads to the reduction of essential minerals in the body, one being potassium. 

How to Consume Enough Potassium for Fluid Retention 

Potassium is available in potassium salts (chloride and bicarbonate). It is also present in various mineral chelates (aspartate, citrate, etc.) and food-based sources. 

Some good food sources of potassium are peas, beans, turkey, fish, salmon, spinach, tomatoes, raisins, greens, beets, greens, mushrooms, and soy products.

Since taking higher doses of potassium salts is risky, it is better to stick to water retention supplements or food sources.  

There are also some popular salt substitutes - NoSalt and Nu-Salt. These are potassium chloride and supply 530 milligrams of potassium per 1/8 teaspoon. 

Are There Any Side Effects? 

When potassium salts are given in higher doses, it may cause side effects such as vomiting, nausea, diarrhea, and ulcers.  

Potassium supplements are not without side effects. Common side effects of these supplements are nausea, vomiting, diarrhea, and stomach upset. These gastrointestinal side effects can be minimized by taking potassium supplements with meals or taking the capsule form of the supplements.

Excessive ingestion of potassium supplements could potentially lead to hyperkalemia. This is because the kidneys cannot remove potassium from the body as fast as it is being added through supplements.

However, hyperkalemia through this means is rare since a high number of potassium supplement pills will be required to produce this cumulative effect.

However, taking it from food sources does not cause any side effects. Thus, it is recommended that you include fresh fruits and vegetables in your diet to maintain good health.