Drinking Too Much Cola Can Lead To Muscle Paralysis

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Article Date: 19 May 2009 - 8:00 PDT

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Researchers in Greece carrying out a review of cases of patients suffering symptoms ranging from mild weakness to profound muscle paralysis are warning about excessive cola consumption that can lead to hypokalaemia, or low levels of blood potassium.

The research was led by Dr Moses Elisaf from the Department of Internal Medicine at the University of Ioannina, Greece and is to be published in the June issue of International Journal of Clinical Practice, IJCP.

Elisaf said in a prepared statement that:

"We are consuming more soft drinks than ever before and a number of health issues have already been identified including tooth problems, bone demineralisation and the development of metabolic syndrome and diabetes."

But there is mounting evidence that excessive cola consumption also results in low blood potassium or hypokalaemia, which adversely affects vital muscle functions, said Elisaf.

In the cases that Elisaf and colleagues reviewed, the patients fortunately fully recovered after they stopped drinking cola and increased their potassium intake either intravenously or with tablets.

The researchers looked at cases where patients had been drinking between 2 and 9 litres of cola a day.

One case, a 21-year-old pregnant woman, was drinking up to 3 litres of cola a day when admitted to hospital after complaining of feeling fatigued, losing her appetite, and vomiting persistently. Blood tests showed she had low potassium and an electrocardiogram showed she had a blockage in her heart.

Another pregnant woman also had low potassium levels and was complaining of muscle weakness that was getting worse. She had been drinking 7 litres of cola a day for 10 months.

In an accompanying commentary, Dr Clifford Packer from the Louis Stokes Cleveland VA Medical Centre in Ohio said he knew of a case of an Australian ostrich farmer who returned from the outback complaining of muscle weakness. It turned out he had been drinking 4 litres of cola every day for 3 years and this went up to 10 litres a day when he was in the outback.

Packer then related the case of a patient of his who had complained of muscle weakness and drank up to 4 litres of cola a day, which he carried around in the basket of his electric scooter. He refused to give up the cola but did cut his consumption by half, and the symptoms improved.

The global consumption of soft drinks is over 500 billion litres a year, or about 80 litres per person and is set to go up to over 90 within the next 5 years. The Americans are the largest consumers: they drink over 200 litres per person per year.

According to Elisaf, there are three ingredients in cola that lead to low potassium: glucose, fructose and caffeine.

But exactly how each compound causes low potassium is not known, and could be different in different people, he said, except that in the cases they reviewed, it appeared that caffeine was probably the main cause.

"This has been borne out by case studies that focus on other products that contain high levels of caffeine but no glucose or fructose", he explained.

However, fructose can cause diarrhea, and this could also lead to hypokalaemia, he added.

Elisaf and colleagues said that in a world where portion sizes are getting bigger and bigger, too many people are drinking too much cola, and this has real implications for public health.

Although most patients recover when they stop consuming cola, and take potassium supplements, chronic hypokalaemia brought on by excessive cola consumption can leave them susceptible to potentially fatal side effects such as irregular heartbeats, he said.

"In addition, excessive consumption of any kind of cola can lead to a range of health problems including fatigue, loss of productivity and muscular symptoms that vary from mild weakness to profound paralysis," added Elisaf, saying that further studies should now be done to decide what is too much when it comes to cola drinking.

Packer said that doctors should add cola consumption to their checklist when asking patients questions about what could be causing their low potassium.

"And 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," he warned.

Packer said there is reason to believe that low potassium due to excessive cola drinking is not rare.

"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 industrialised countries drink at least 2-3 litres of cola per day," he said.

A spokeswoman from the British Soft Drinks Association told the BBC that the examples Elisaf and colleagues had reviewed were very extreme cases.

"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," she said, adding that her industry was committed to encouraging people to consume its products responsibly.

"Nutrition labelling is included on pack so people can make an informed choice about the products they are drinking," she said.

IJCP

Sources: Wiley Blackwell, BBC News.

Written by: Catharine Paddock, PhD
Copyright: Medical News Today
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