Earlier this month, the global drinks giant Coca-Cola dropped out of an annual list of the world's top 10 brands for the very first time; having come third in 2010, the company found itself in 16th place, and the fall, analysts said, was in part fuelled by the fact that consumers are increasingly choosing "healthier drinks" over traditional fizzy pop.
The shift in our drinking habits over the past two decades has been remarkable: the global rate of bottled water consumption quadrupled between 1990 and 2005, and today the industry is worth some £2bn in the UK alone. Over the last few years we have seen an explosion in enhanced waters – not only flavoured waters (Volvic's Touch of Fruit, Britvic's Drench, This Water, Pret a Manger's Pure), but also waters with added vitamins and minerals (Vitaminwater), electrolytes (SmartWater), not to mention waters that promise to aid energy levels, concentration, sleep, sex and relaxation (Neuro drinks). The predicted growth of the market can be judged by Coca-Cola's 2004 buyup of Energy Brands Inc (which makes Vitaminwater), which was the largest purchase in Coca-Cola's 115-year history.
But are these drinks any healthier than, say, lemonade or cola? Certain flavours of This Water (the flavoured water range that shares a parent company with Innocent) contain 42g of sugar per 420ml bottle (a 500ml bottle of Coca-Cola contains 53g of sugar).
"The nutritional information is clearly stated on all our drinks labels," says Sarah Smart, This Water's marketing manager. "This Water drinks are made from pure squeezed juices from real fruits, spring water and sugar. The sugars found in our drinks are made up of the sugars in fruit juice and sucrose, which is needed to ensure that our drinks taste great – without it, they would taste too sharp. Unlike other flavoured water brands, our drinks will never contain concentrates, colourings or preservatives."
The problem with the enhanced water market is in part one of perception – as consumers, we associate the words "vitamins" and "fruit" and even "preservative-free" with a healthy diet, and give little thought to less desirable ingredients.
In January, the Advertising Standards Agency declared an advert that claimed Vitaminwater was nutritious "misleading"; while the drink promises much by way of added vitamins, including 100% of the recommended daily allowance (RDA) of vitamin C, and while it does qualify as a "low-calorie" drink by EU guidelines, each 500ml bottle also contains the equivalent of around five teaspoons of sugar – about a quarter of the consumer's guideline daily amount.
"We have always been completely transparent that the drinks contain 23g of sugar in each 500ml bottle," a spokeswoman said, adding that its flavours and colourings are now "naturally derived" and that the drink "provides a convenient way to help people hydrate and get more of the vitamins and minerals they may require".
Of course a drink that promises extra vitamins, not to mention improved focus, sex or sleep, cannot help but seem alluring. Neuro Bliss, for instance, claims to be "designed to promote happiness and eliminate stress without affecting your energy levels" and states that it "works immediately". It contains L-Theanine, an amino acid found in green tea, to aid relaxation and mental function, phosphatidylserine, which "may help to maintain and improve healthy mental performance" and vitamin D3, which "supports healthy bones; may help support cognitive function and immunity". Should we be sceptical?
"For these claims to appear on a label," explains Bridget Benelan of the British Nutrition Foundation, "they have to either comply with the European Commission approved list, or be going through the process of applying for that approval." But the EC regulation has only been in place since 2007, and since thousands of appeals have been submitted, it is understandably taking a long time to check them all.
"A lot of them haven't got through," Benelan says. "For example, some probiotics, as well as the link between omega 3 and cognitive function. But vitamin D's link to bone health has been proved, and as long as there's more than 15% of the recommended daily amount in the drink, they can make that claim." Neuro Bliss contains 50% of the RDA of vitamin D3.
While such drinks can do no harm as an occasional treat, it is the cumulative effect of drinking them regularly, and in large quantities, that could prove harmful: a 2009 study found that Americans now obtain 25% of their calories from liquids.
"If people are consuming large quantities of things with a high calorie content, then there is reason to worry," says Benelan. "If we want something to drink, it's usually because we're thirsty, not because we need energy – and it's unlikely to mean that later we don't eat something because we've consumed calories from that drink."
• This article was amended on 1 April 2011. The original said a 500ml bottle of Coca-Cola contained 35g of sugar. This has been corrected to 53g. The headline was amended to remove a reference to health drinks containing more sugar than Coke.
