Cola's not always cool

The rising temperature may tempt you to pour litres of chilled cold drinks down your parched throat, but have a care. Recent articles in reputed medical journals have reported a hitherto unknown side effect of glugging huge quantities of cola.

The International Journal of Clinical Practice reported recently that an Australian ostrich farmer who used to drink four to 10 litres of cola a day has developed lung paralysis. In yet another case reported in the journal, a pregnant woman, who had been consuming three litres of cola a day for the last six years, complained of loss of appetite, persistent vomiting and an irregular heart rate. Both patients were suffering from cola-induced hypokalemia or low blood potassium levels, which lead to muscle paralysis, the journal said.

It’s enough to get the medical community worried — especially in the West, where consumption of colas is generally quite high. Of course, it hasn’t been conclusively proved that the consumption of excessive amounts of cola can lead to muscle paralysis. Asserts Arvind Varma, secretary general of the Indian Soft Drinks Manufacturers Association (ISDMA), which represents all leading cola brands marketed in India, “There is no clinical evidence to prove soft drinks can cause such harmful effects. The examples cited are all extreme cases of chronic consumption. Moderate consumption of cola drinks is safe and people can continue to enjoy such drinks as part of a sensible, balanced diet and active lifestyle.”

The ingredients in aerated drinks are primarily carbonated water, phosphoric acid, high fructose corn syrup (sugar), caramel colour, natural flavours and caffeine. A recent study by the University of Ioannina, Greece, suggests that hypokalemia can be caused by excessive consumption of three of the most common ingredients in soft drinks — glucose, fructose and caffeine.

Not everyone agrees. UK-based physician Dr Apurba Chatterjee finds it “very difficult to conclude that colas cause a drop in blood potassium levels”. However, he does concede that “the large glucose load in such drinks can cause increased renal potassium wasting. Such drinks also contain large amounts of high-fructose corn syrup that send largely indigestible fructose into the gastro-intestinal tract, causing potassium wasting via osmotic diarrhoea”. But you would need to consume many gallons of cola on a sustained basis before you can develop hypokalemia or potassium deficiency, adds Dr Chatterjee.

Even if you drink a smaller amount of cola, there can be some side effects. “Though India has one of the lowest per capita consumption of soft drinks, the ill effects among the urban population, particularly children, is quite alarming,” says Calcutta-based physician Dr Kanchan Gurtu. Child obesity is a problem too as colas have a high sugar content and almost no nutritional value, says paediatrician Dr Santanu Ray.

Needless to say, people in the cola industry do not agree. “Today’s kids lead a sedentary life. They watch a lot of television, play video games, and eat junk food. Aren’t these factors contributing more to their obesity than cola consumption,” counters an official at Coca Cola, who refused to be named.

Colas could be harmful for menopausal women too, say experts. “The level of oestrogen, the hormone that controls calcium metabolism, falls in menopausal women. Colas might interfere with the calcium metabolism further, aggravating osteoporosis,” says Pulak Lahiri, former Nilratan Sarkar Professor at Ballygunge Science College, Calcutta. Osteoporosis is caused when calcium is sucked out of the bones, making them brittle. Drinking too many soft drinks may increase phosphate levels in the blood, which can lead to calcium being leached out of the bones.

“Soft drinks can also cause dental decay,” points out Calcutta-based dentist Dr Saon Barman. “They lead to tooth decay and caries when consumed by children on a regular basis since the high sugar content assists the growth of bacteria.”

The caffeine content in most cola drinks can also have certain side effects. “Colas contain caffeine that acts as a stimulant to the central nervous system, leading to insomnia, nervousness, anxiety and irritability,” says Dr Ray.

Varma, however, insists, “All members of the ISDMA follow limits of caffeine content and other ingredients as prescribed by the ministry of health, Government of India.”

Of course, nutritionists feel that the best thing would be to avoid colas altogether. Says Karnika Ghosh Das, dietician at BM Birla Hospital, Calcutta, “Ideally, people should avoid cold drinks and settle for healthier options such as fruit juice, buttermilk or coconut water.”

But if you have to have a fizzy fix, do it in small measures. An over indulgence in colas can lead to all sorts of potential health risks.