Overusing watermelon can be dangerous for people suffering from chronic kidney disease. A clinical case study, published in the journal
Annals of Internal Medicine
, details how three patients developed severe hyperkalemia, or high levels of potassium in the blood, after eating too much of this fruit, although it is excellent for health.
High potassium interferes with cells
Made up of 90% water, watermelon is also rich in potassium. A quarter of the fruit contains 320 mg, the study specifies. This mineral contributes in particular to the proper functioning of the nervous system and is essential for muscle contraction. But high levels of potassium in the blood, called hyperkalemia, can also interfere with the functioning of nerve and muscle cells. Especially when it is not properly eliminated by the kidneys and released into the urine.
Severe hyperkalemia manifests itself “primarily by heart rhythm disturbances,” notes the MSD Manual. It can be responsible for muscle weakness, paralysis, cardiac abnormalities or cardiac arrest in the most serious cases. A diet very rich in potassium can be the cause and the risks are increased in the event of kidney problems which prevent the kidneys from eliminating potassium in sufficient quantity.
Reducing watermelon consumption effective
The first clinical case reported in the study concerns a 56-year-old man suffering from renal failure. The patient was admitted to intensive care after losing consciousness for around fifteen seconds. His heart rate notably dropped to 20 beats per minute while the heart generally beats between 60 and 100 times per minute. Analyzes showed a high level of potassium in his blood, which doctors explained by the fact that the patient ate watermelon every night in the two months preceding his hospitalization.
In the second case, the 72-year-old man described drinking two glasses of watermelon juice every day in the month before his admission to hospital, while in the third case of "severe hyperkalemia", a woman 36-year-old reported eating large quantities of watermelons for three weeks.
In all cases, reducing the consumption of watermelon, sometimes associated with taking medication, has helped reduce the level of potassium in the blood. The case study “highlights the importance of dietary advice in patients with advanced chronic kidney disease, including end-stage renal disease,” the study authors point out.