Researchers call for greater study of maximum cola intakes

In findings appearing in the International Journal of Clinical Practice, prolonged heavy consumption of cola products, particularly in the case of pregnant women, was linked to affecting potassium homeostasis, creating significant but reversible health problems.

Representatives of soft drink manufactures have hit out at the findings by researchers from the University of Ioannina, Greece, claiming the levels of consumption linked to the onset of conditions were well beyond its own position on recommended intake.

Hypokalaemia​

Hypokalaemia, a term used to describe low blood potassium, has been found to be severely detrimental to the function of cells in the body, according to some findings.

Researchers on the study suggest several case studies where long term consumption, at a rate of between two to nine litres a day, had led to concerns over the sensitivity of pregnant woman to high intakes of cola-drinks.

“In addition to the pregnancy-related cases of cola-induced hypokalaemia, several other reports on non-pregnant individuals emphasise the adverse effects of ​cola over consumption on potassium metabolism,”​ state the researchers. “The most common complaints were muscular in origin and ranged from mild weakness to profound paralysis.”​

Mechanisms​

Looking to clinical studies dating back to 1993, the study identifies three different mechanisms potentially responsible for what it calls ‘cola-induced hypokalaemia’.

These mechanisms included the impact of consuming large amounts of glucose, often found in cola products that it says, in sufficiently large quantities, can lead to osmotic diuresis and inappropriate urinary potassium loses.

In addition to this factor, concerns are also raised over the potential impact of high-fructose corn syrup (HFCS) that can contain a number of corn syrup formed from enzymatic processing, on inducing hypokalaemia. After being mixed with pure corn syrup to become a HFCS, researchers say the ingredient, when not ingested in the form of sucrose, is absorbed in limited amounts.

“Large amounts of unabsorbed fructose pass into the colon where they may result in the development of osmotic diarrhoea,” ​claim the researchers. “Indeed, previously published reports have underscored the role of HFCS in the development of chronic osmotic diarrhoea and potassium depletion.”​

The final possible mechanism highlighted in the study was linked to the levels of caffeine often found to be present in cola drinks.

In light of these potential concerns, researchers called for further study to identify maximum consumption levels of cola-drinks before becoming a risk.

“Although cola discontinuation and potassium supplementation usually lead to an uneventful recovery in the most of the cases, the cola-induced chronic hypokalaemia clearly predisposes to the development of potentially fatal complications such as cardiac arrhythmias,”​ the study concludes.

Drink makers response​

The findings and calls for further study have been criticised by the British Soft Drink Association (BSDA) though, which says that case studies used in the report are based on small sample size and are not therefore sufficient in their findings.

“The examples used in this paper by the IJCP are all very extreme cases of high cola consumption, which are totally unrepresentative of the cola consumption of the vast majority of people in the UK,”​​states the trade group. “Moderate consumption of cola drinks is completely safe and people can continue to enjoy such drinks as part of a balanced diet and active lifestyle.”​

The statement itself did not outline or define intake levels deemed to represent moderate consumption.

Source: International Journal of Clinical Practice​

June 2009, Volume 63, Issue 6, Pages: 900-902

"Cola-induced hypokalaemia: pathophysiological mechanisms and clinical implications"​

Authors: V. Tsimihodimos, V. Kakaidi and M. Elisaf