Despite remaining below 2 per cent of total bottled water volume in any country, oxygen enhanced waters have seen fantastic growth since their launch. In a new report Zenith International predicts that global sales will double by 2008, but that companies will need to focus on explaining their products' benefits more clearly.
In Germany, a large part of the growth, is down to the strong performance of Adelholzener's Active O2 brand, said Zenith. The product claims to "assist the body to take in extra oxygen". The brand is now so large that it advertises at a national level and is starting to export to other markets such as Austria and the UK.
Undoubtedly good business, but scientists are a bit dubious about the claim, which seems to be subject to relatively little scrutiny or legislation. Most oxygenated brands state, and some imply, that oxygenated water improves physical performance and fitness.
Scientists do not concur. A research letter published in the Journal of the American Medical Association in November 2003 compared five different brands with well-stirred tap water. It showed that drinking oxygenated water before exercise does not improve performance.
Other studies have also had similar results. None have caused great surprise; the amount of extra oxygen that can be dissolved into a 500ml bottle of water is about the same as one breath of air. Most of this oxygen escapes as soon as the product is opened and the stomach's rate of oxygen absorption is microscopic in comparison to the lungs.
"It's a difficult claim to prove," agreed the report's author Sophie Carkeek. "To move into the bottled water mainstream, research supporting the benefits needs to convince both the industry and consumers." But, success in Germany seems to have been relatively unimpeded without science.
The appeal of the products as being 'pure', as well as their novelty factor, is valuable on its own. Bubbles can be seen rising as the bottle is opened and the concept of the water has given rise to eye-catching design concepts and brand images. For example the brand OGO, which is gradually being released in UK shops, is sold in a round bottle. And, the German producer of Active-O2, Adelholzener Alpenquellen, is owned and run by Bavarian Nuns, who are pictured on the website in the bottling plant.
But, in the United States, something very different is happening. The sector has seen a much more modest growth of 10 per cent (4 million litres) and a significant share of this, according to Zenith, can be attributed to the leading brand, Penta Water. It is not an oxygen enriched water, but a 'clustered water'.
Clustered water is molecularly restructured to create clusters of smaller molecules for more rapid absorption. Unlike many oxygenated water brands, Penta can actually cite scientific studies from peer-reviewed journals to back up its claims: first of all, the water is actually different (it has a different boiling point) and secondly, it has a possible benefit to health (faster and more effective hydration).
As it attempts to grow into new markets outside the US and Germany, it is uncertain whether oxygenated and clustered varieties of enhanced water will show the same level of growth. It is likely, however, that they will be roughly aiming at the same fitness conscious consumer.
Clustered water manufacturers could easily up the stakes scientifically, but to be successful, would still need to combat the strong brand image that products such as Active-02 and OGO are developing. Penta is already available for purchase in the UK.