Three litres of cola a day significantly reduced blood potassium levels
British doctors have described a case of a 30-year-old man who has had recurrent episodes of significant drops in blood potassium - hypokalaemia - over the past five years. A study of his diet revealed that he drank 3 to 3.5 litres of cola daily. After a significant reduction in cola intake and the administration of potassium preparations, his blood potassium levels returned to normal. The case is described in BMJ Case Reports.
Hypokalaemia, defined by a serum potassium level of less than 3.5 millimoles per litre, occurs in 20 per cent of hospitalised patients. It may not present with significant clinical symptoms, but can lead to fatal heart rhythm abnormalities and muscle weakness. It usually occurs due to renal dysfunction, medication, vomiting or diarrhoea and endocrine disorders.
Meanwhile, dietary and lifestyle factors can also have a significant impact on blood potassium levels. For example, excessive consumption of watermelon, which is rich in potassium, can lead to dangerously high levels of this element. And recent studies have shown that excessive consumption of certain drinks, especially carbonated drinks, can lead to the development of hypokalaemia. It has been suggested that the hypokalaemia associated with excessive cola consumption is related to its diuretic properties, but there is still no unanimity in recognising the pathogenesis of this disorder.
A team of doctors led by Mohamed Ahmed of Milton Keynes College described a case of hypokalaemia in a 30-year-old British man. The patient was taken to hospital by ambulance after complaining of central chest discomfort with palpitations, muscle spasms and anxiety. At the same time, the patient had been to the emergency department four times with the same complaints. He had a history of brief episodes of confusion, visual and auditory hallucinations.
The patient had experienced similar symptoms a couple of days earlier while abroad and had gone to hospital, where his blood potassium level had been tested at 3 millimoles per litre and he had been prescribed potassium replacement therapy. He is currently taking citalopram (antidepressant), ramipril (angiotensin-converting factor inhibitor), amlodipine (slow calcium channel blocker), pramipexole (dopaminomimetic) and effervescent potassium tablets. There was no history of liquorice ingestion with food. The patient had a history of severe mental health problems including ADHD, autism, learning difficulties, depression and paranoia.
He also had hypertension and recurrent episodes of hypokalaemia since 2018. Physical examination revealed no significant abnormalities, the patient seemed mildly confused and restless. Except for a slightly rapid heart rate (116 beats per minute), vital signs were within normal limits. Laboratory studies showed that the patient had significant hypokalaemia with a potassium level of 2.8 millimoles per litre with no significant changes on electrocardiogram. The patient works in information technology, does not smoke, and denies illicit drug use, but admits to drinking 2-3 cans of beer per day. On further questioning, he admitted to drinking approximately 3-3.5 litres of cola per day, resulting in frequent urination (5-6 times per day).
The patient was prescribed potassium replacement therapy and advised to stop drinking cola. Examination six days later in the emergency department showed normal potassium levels. After conducting a brief review of the literature, the physicians suggested that the hypokalaemia with increased cola consumption may be due in part to exposure to excess caffeine. In addition, the effects of cola components on the aldosterone axis of regulation of blood potassium concentration may be possible.