Potassium and diabetes: what is the link?

Potassium is an essential mineral that has some vital functions in the body. It regulates blood pressure, prevents water retention in the body and protects against stroke, osteoporosis and kidney stones. Studies also suggest that low blood potassium levels may increase the risk of diabetes. In this article, we will take a detailed look at the link between diabetes and potassium.

What is diabetes?

Diabetes is a disease that afflicts millions of people around the world, and its treatment costs billions of dollars each year (1).

There are several types of diabetes, and its primary symptom is high blood sugar levels (hyperglycemia).

Type-1 diabetes is an autoimmune disease leading to lack of insulin.

Beta cells of the pancreas are responsible for insulin production and in patients with type-1 diabetes some autoimmune reactions destroy these cells.

Insulin helps move the glucose from the blood into muscles, fatty tissue, and heart muscle (myocardial) cells.

If your pancreas cannot produce enough insulin, the glucose will remain in your blood and symptoms like hyperglycemia, frequent urination and excessive thirst.

Why?

Your brain regulates the internal environment of your body and tries to get rid of the excess of any substance, which may affect pH levels, including glucose, potassium or sodium through urine, stool, breath, perspiration, etc.

Yet, the more you urinate, the more you need to drink to prevent dehydration.

Thirst is a signal that your body does not have enough fluids.

Symptoms of type 2 diabetes are like those of type 1 diabetes, but the cause of the disease is different.

While in type 1 diabetes your pancreas does not produce enough insulin, in type 2 diabetes you may have enough insulin, but your cells fail to respond to it adequately, due to insulin resistance. Thus, glucose (sugar) cannot get into the tissues and remains in the blood, leading to hyperglycemia.

Diabetes is associated with many serious illnesses. In particular, it damages the kidneys, eyes, blood vessels and nerves and may cause dangerous fluctuations in potassium levels.

How does diabetes cause hypokalemia?

Electrolyte imbalance is a common problem for people with diabetes. When you have too much glucose in your blood, your kidneys start to filter the glucose out from the body, through urine, including other ions, such as potassium, phosphates, and magnesium, leading to hypokalemia, hypophosphatemia, and hypomagnesemia (e.g., low levels of these ions).

The most significant loss of potassium and other ions occurs in acute complications of diabetes, such as diabetic ketoacidosis and diabetic hyperosmolar coma (2).

But what is the link between diabetes, insulin and hypokalemia?

The normal blood potassium level is 3.6 to 5.2 millimoles per liter (mmol/L). If your blood potassium level drops below 3.6, you have hypokalaemia.

Diabetes causes hypokalaemia by several different mechanisms.

Administration of insulin leads to the transfer of potassium ions from the blood into the cells, which decreases the blood potassium level (3).

Insulin allows glucose transport into the cells and also activates the H+/K+ pump, which transfers potassium ions from blood to the cells in exchange for hydrogen ions.

Diabetes may also cause digestive issues, such as diarrhea or intestinal bacterial overgrowth, which impairs potassium absorption from food.

The third reason why diabetes may cause hypokalaemia is the loss of potassium ions through the kidneys.

In the early stages of diabetes, you pee a lot, so you are more prone to low potassium. Later, you may become dehydrated, your kidneys stop working, you stop urinating and the potassium level increases (see below).

Many people are potassium deficient.

The symptoms of hypokalaemia include constipation, palpitations, skipped heart beats, fatigue, muscle weakness, tingling and numbness on hands, feet or any other part of the body. Due to the risk of heart rhythm disorders (arrhythmias) and cardiac arrest doctors need to monitor potassium levels in people with diabetes and, if necessary, correct the fluctuations by intravenous or oral potassium.

Sometimes, potassium levels in diabetics may fluctuate even if you get enough potassium from diet or take it as a medicine or dietary supplement. This is due to potassium shift in the body (exchange of potassium between cells and blood).

Should a person with diabetes take potassium supplements?

Despite the fact that hypokalaemia can be dangerous, you should never take any potassium supplements without prior consent or advice of your physician.

Potassium supplements sold on the market may increase potassium levels in the blood and cause hyperkalemia (high blood potassium levels).

This condition is as dangerous as low potassium because it may also lead to heart rhythm changes and cardiac arrest.

How to get enough potassium?

Only 3% of Americans have an adequate potassium intake.

While U.S. health associations recommend a daily potassium intake of 4.7 grams, WHO recommends 3.15 g (4).

The best food sources of potassium for people with diabetes include:

• fat fish such as tuna or salmon
• potatoes
• beans
• yogurt

Some fruits such as bananas or peaches also contain a lot of potassium, but if you have diabetes, you should consume them in moderation.

Watch out for hyperkalemia, too

Unfortunately, the relationship between potassium and blood sugar is not as simple as you may think.

While insulin typically lowers blood potassium levels, people with diabetes may also be at risk of hyperkalemia (high blood potassium level), which is as dangerous as low potassium, because it disturbs the heart rhythm and can cause death.

What is the link between diabetes and high blood potassium levels?

In people with diabetes, potassium levels often fluctuate even without increasing your potassium intake from supplements, foods or otherwise.

Diabetes and related diseases cause potassium ion shift from cells (intracellular compartment) to the blood (extracellular compartment) and vice versa.

Therefore, you may sometimes experience your potassium blood levels go down (hypokalaemia) while at other times they may become dangerously high (shift hyperkalemia).

The most common causes of hyperkalemia in people with diabetes include acidosis, cell lysis, renal insufficiency, and insulin deficiency (4).

Acidosis

The human body regulates the pH level strictly (the normal range is between 7.36 - 7.44), which is necessary for proper coordination of metabolic reactions and functionality of enzymes.

The potassium level in the blood rises by 0.4 mmol/L for each drop in pH by 0.1.

Diabetic ketoacidosis is a common complication of diabetes.

It means that your blood pH level falls below 7.3 and your body starts using ketones as the primary source of energy, instead of the glucose.

Here is a more detailed explanation.

If your body does not produce enough insulin, the glucose transport from blood to cells is impaired.

As glucose is the primary energy source for the majority of cells in the body, including the brain, your body needs to look for other sources of energy and starts to break down fats to make ketones.

These substances are acidic, which leads to pH decrease and diabetic ketoacidosis.

Besides, ketones in the blood increase the H+ ion levels, which makes acidosis even worse. Your body tries to compensate for the ketoacidosis by various mechanisms, and one of them is based on the exchange of H+ ions and K+ ions. The H+ ions get shifted from the blood to cells, and the K+ ions get transferred from the cells to the blood. 

Usually, your kidneys get rid of the excess potassium in the urine (this is why frequent urination is an early symptom of diabetes and diabetic ketoacidosis).

However, people with diabetics produce so much urine that they cannot drink enough water to make up for the loss and become dehydrated.

Dehydration impairs the excretory functions of the kidneys, and potassium begins to accumulate in the blood, resulting in hyperkalemia.

Cell lysis

Potassium is the primary intracellular ion, which means that it is mainly found in the cells.

People with diabetes often get a disease called rhabdomyolysis, which means "death of muscle cells".

When a cell dies, the potassium can freely flow out and cause hyperkalemia.

Renal failure

Dehydration, acute and chronic kidney diseases may impair potassium excretion in the urine, which leads to potassium build up and hyperkalemia.

Drugs

Cardiovascular diseases and hypertension are other frequent complications of diabetes.

Some medicines used to treat these diseases, including ACE inhibitors, beta-blockers, potassium-sparing diuretics, angiotensin II receptor blockers, and renin inhibitors, may increase potassium levels in the blood and cause hyperkalemia.

Metformin and hyperkalemia

Metformin is a medicine used in people with diabetes to increase the sensitivity of cells to insulin and to decrease insulin resistance.

Its use may be associated not only with digestive problems, such as diarrhea or bloating but in rare cases, it may also cause lactic acidosis and hyperkalemia (5).

Lactic acidosis is a life-threatening complication of diabetes.

The risk of hyperkalemia and lactic acidosis is higher in patients with renal impairment as well as in those who drink alcohol.

Therefore, if you are taking metformin, you should not drink any alcohol.

If you are on medication that affects blood potassium levels, your doctor will monitor your potassium levels very carefully.

The takeaway

Diabetes may cause both low and high potassium because it affects not only the metabolism of glucose but also other organs in the human body.

High levels of insulin cause hypokalaemia, while low insulin levels are associated with hyperkalemia.

The blood glucose levels are directly proportional to potassium levels in the blood, which means that the higher blood sugar you have, the higher the potassium concentration is.

Do not take any potassium supplements without prior permission of your doctor.

They will not help you because the potassium level fluctuations in diabetic patients are not related to its intake, but to the transfer of potassium between the blood and the cells (potassium shift).

If you want to decrease the risk of blood potassium level fluctuations, eat and drink regularly, measure your blood glucose frequently and take insulin or other medical drugs as prescribed and directed by your doctor.