HIGH COLA CONSUMPTION AND HYPOKALEMIC MYOPATHY

NEW YORK (Reuters Health) Jun 05 - Drinking several liters of cola-containing soft drinks per day can cause chronic hypokalemia leading to muscle weakness and even paralysis, according to a review article in the International Journal of Clinical Practice for June.

While one might argue that "excessive soft drink consumption at this level is so rare that it is not a public health issue," the author of an accompanying editorial writes, "the problem is that we have every reason to think that it is not rare."

In a search of PubMed, Dr. Moses Elisaf and associates at the University of Ioannina, Greece, identified six reports of cola-induced hypokalemia published since 1994. Quantities of cola consumed ranged from 2 to 9 liters/day. Muscle complaints ranged from mild weakness to profound paralysis, and all patients had abnormally low serum potassium levels.

"Fortunately," Dr. Elisaf and colleagues write, "all patients had a rapid and complete recovery after the discontinuation of cola ingestion and the oral or intravenous supplementation of potassium."

The authors suggest that one component with the potential to alter potassium metabolism is high-fructose corn syrup, which can cause chronic osmotic diarrhea and potassium depletion. Glucose -- by inducing osmotic diuresis and hyperinsulinemia - or caffeine - by causing potassium redistribution into cells and/or increased renal potassium excretion - may also be responsible.

Dr. Elisaf's team cautions that "the cola-induced chronic hypokalemia clearly predisposes to the development of potentially fatal complications such as cardiac arrhythmias."

In his editorial, Dr. Clifford D. Packer at the Louis Stokes Cleveland VA Medical Center in Cleveland, Ohio, comments that "with aggressive mass marketing, super-sizing of soft drinks, and the effects of caffeine tolerance and dependence, there is very little doubt that tens of millions of people in industrialized countries drink at least 2-3 L of cola per day."

The resulting drop in serum potassium levels increases the risk of cardiac ischemia, heart failure, or left ventricular hypertrophy. He also notes that sugar-sweetened soft drinks have been linked to osteoporosis, gout, GERD, chronic kidney disease, secondary hyperparathyroidism, esophageal perforation, hematuria, tongue erosions, and gastritis.

Dr. Packer advises physicians to start asking their patients about soft drink consumption, and stresses that "the soft drink industry needs to promote safe and moderate use of its products for all age groups, reduce serving sizes, and pay heed to the rising call for healthier drinks."

Int J Clin Pract 2009;63:833-835,900-902.