Avoid Eating Bananas If You Have This Medical Condition

Bananas really are the jack-of-all-fruits. They blend perfectly into your morning smoothie, add moisture and flavor to your breads and cupcakes, and add sweetness to your cereal bowl. And if you're on the go, they're the ultimate grab-and-go snack.

They're not only convenient and wallet-friendly, but bananas are also packed with nutrients and fiber, so there's a lot to love about them. According to Healthline, they're free from fat and cholesterol and come loaded with vitamins C and B6, phytonutrients, and antioxidants.

But let's not forget, bananas are famously rich in potassium. According to the US Department of Agriculture (USDA), a medium banana packs 422 milligrams of potassium. Healthline notes that potassium is an essential electrolyte, crucial for keeping our body's fluid levels balanced and ensuring our muscles and nerves function optimally.

That being said, bananas can cause problems when eaten in excess, especially for people instructed to limit their potassium intake — particularly those with kidney disease.

One of the kidneys' primary roles is the regulation of potassium levels in the body. Damaged kidneys can't function properly and may cause potassium to build up in the blood, leading to hyperkalemia. According to the National Institutes of Health, hyperkalemia can cause problems like life-threatening cardiac arrhythmias, paralysis, and muscle weakness.

What is kidney disease?

Kidneys are two bean-shaped organs, each about the size of a fist. Kidneys filter excess waste and blood from the blood and produce urine, processing about half a cup of blood every minute, according to the National Institutes of Health.

Kidney disease can be acute or chronic. Acute kidney injury is a temporary condition, often triggered by an illness or injury, which disrupts kidney function. Chronic kidney disease, on the other hand, involves permanent damage to the kidneys and can lead to lasting impairment of kidney function, as noted by Kidney Health Australia.

Examples of short-term kidney injuries are interstitial nephritis, a condition that arises when certain medications impede the kidneys' capabilities, and pyelonephritis, caused by a urinary tract infection that ascended to the kidneys.

Chronic kidney disease includes conditions that progressively impair kidney function. Polycystic kidney disease, a hereditary disorder, causes cysts that disrupt kidney filtration, potentially worsening over time. Lupus nephritis, an autoimmune disease, leads to permanent kidney damage through scarring, as detailed by WebMD.

Kidney disease and potassium

One of the roles of the kidneys is the regulation of potassium homeostasis in the body, or the amount of potassium absorbed and excreted from the body through the blood, according to a 2015 study published in the Clinical Journal of the American Society of Nephrology.

Centers for Disease Control and Prevention (CDC) underscores that chronic kidney disease means that the kidneys are so damaged that they can no longer filter blood as they should. This leads to the accumulation of waste and excess fluid in the body, and additionally, this can lead potassium to build up in the blood, leading to hyperkalemia.

The National Kidney Foundation highlights that hyperkalemia often presents without noticeable symptoms. When symptoms do occur, can start off slow, generally developing gradually over weeks or months. Symptoms can include numbness, tingling, muscle weakness, and nausea, 

However, hyperkalemia can also come abruptly and in a severe manner, which can pose a life-threatening risk. In such cases, individuals may experience acute symptoms including shortness of breath, heart palpitations, nausea, vomiting, and chest pain.

Hyperkalemia, often unnoticed due to symptom absence, can result from diets high in potassium-rich foods, like bananas, in those with kidney damage. Centers for Disease Control and Prevention (CDC) explains that numerous individuals with chronic kidney disease are unaware they have the condition, often due to the absence of symptoms. The only definitive way to diagnose chronic kidney disease is through laboratory tests that evaluate the protein content in urine and creatinine concentrations in the blood.