Along the way, they help us to digest our food, concentrate harder, improve our memory function, delay the ageing process and become more accomplished lovers. At least, that's the theory. No wonder the global market for such beverages now stands at $48.2bn, according to Datamonitor figures for 2010 a 3% increase on the previous year. Over the next four years, the organisation expects further growth of 29%, taking the market value to $62.1bn.
In volume terms, the sector grew by 1.6% last year to reach 13.7bn litres pretty much two litres for every person on the planet. It sounds high, particularly to those who might believe the market begins and ends with Red Bull. But functional drinks already have a massive foothold in Asia, a continent that provides a constant stream of inspiration for producers and marketers in the West.
New product development is widespread, and the health claims that accompany it are less overt. This is partly due to a more zealous approach to policing from the European Food Safety Authority (EFSA), but also because consumers themselves have a natural wariness about functional claims, especially if the effects they advertise aren't immediately apparent.
Ram Chaudhari is chief scientific officer with Fortitech, the New York- based nutrients producer, and well placed to assess recent trends. He highlights relaxation drinks as a particular area of activity.
"Ingredients such as GABA [gamma-aminobutyric acid], melatonin and L-theanine are being incorporated more and more into beverage formulations that are designed to help us unwind," he says.
"Weight management beverages that incorporate protein are another area where we are seeing formulation requests on the uptick. While once geared to athletes interested in muscle growth, protein has been determined to promote satiety as well; and beverages fortified with protein are in demand with mainstream consumers interested in weight management.
"New flavour development and technologies associated with it are helping to make more choices available to create a variety of products that deliver good taste."
Barbara McCarthy, project innovation manager for bars and beverages at Irish functional ingredients producer Carbery, says the category is "thriving" as vitamin-enriched, juice-based and calcium-fortified products attract people who previously fixated on sugary fizz. "Consumers are increasingly aware that ingredients such as whey protein can have specific health benefits ... in the weight management and general lifestyle categories," she says.
Ageing and Vitamins
Can functional drinks bestow immortality? Sadly not, but producers know there is an endless quest for food products that will help people live longer, healthier lives. Drinks that offer extra vitamins and anti-ageing benefits are coming to the fore.
Says Chaudhari: "As the baby boomer generation continues to be the largest demographic group worldwide, there will be growth opportunities in these categories. Their nutrient needs change as they age and vitamin-fortified products would be a way for them to fill in their nutrient gaps. Anti-ageing is similar and crosses both genders."
McCarthy adds: "The functional beverages category is rich with products offering general health benefits. What is becoming more popular across the industry, however, is condition-specific functional ingredients. An ageing population means there is high demand for products that cater for problems that present themselves in later life such as joint mobility, muscle strength, brain and heart health."
In the UK, Mintel predicts that, "Age-related health claims are likely to increase in prominence, with demand being driven by consumers' increased desire to stay younger for longer, maintaining their health and looks." However, EFSA's new stance doesn't make this an easy marketing message to use glibly.
Simon Cowell may swear by lingonberry, chokeberry and acerola berry smoothies but, for many people, a more practical (and prosaic) solution is vitamin-enhanced water. This market segment has seen a flurry of recent activity, led by Glaceau, the US-owned brand which combines a range of vitamins with ingredients such as zinc, potassium and taurine.
Despite the success of these products, many commentators have questioned their benefits. The Advertising Standards Authority in the UK recently ordered Glaceau VitaminWater to drop claims that it is nutritious, owing to its high sugar content. A 2010 study by the Department of Chemistry at Scranton University in Pennsylvania found that "fruit juices, on average, contained more than eight times the concentration of free polyphenols [antioxidants] than vitamin-enhanced waters". On a per-calorie basis, fruit and berry juices contained more than twice the amount of free polyphenols, the study found.
Green tea
Green tea extract is one of the most hyped natural ingredients in the sector, and research is backing up many of its producer's claims.
This year, a study in China found that green tea can cut low-density lipoprotein (LDL, the 'bad' cholesterol linked to heart disease) but it has no effect on the high-density equivalent: the 'good' cholesterol.
Researchers at Peking Union Medical College in Beijing conducted a meta-analysis of 14 trials involving 1,136 subjects. Green tea reduced total cholesterol by 7.2mg/dL against subjects taking the placebo. LDL fell by an average of 2.2mg/dL: a little under 2%.
The effects of green tea may be due to catechins, which decrease the absorption of cholesterol in the gut, the researchers said.
The effect is not significant enough for green tea to be promoted as an alternative to cholesterol-busting drugs; indeed in some people, it has been linked with liver damage. But researchers believe green tea can form part of a cardiac-friendly diet, and its benefits extend into other areas too.
Another 2011 study, this time at Texas Women's University in Houston, found that green tea's polyphenols protected skin to some degree against ultraviolet radiation, and also generally improved the skin quality of women who took part in a 12-week double-blind, placebo-controlled test. Green tea is also considered an antioxidant and may help to combat some cancers.
All consumer goods categories rely on retaining the confidence of their audience, and this is as big an issue for the makers of functional drinks.
A UK report published by Mintel last September said: "Consumers may be buying functional food and drink products, expecting to see immediate improvements in their health and fitness once they have consumed them.
"However, given that it would be difficult to see the immediate effects of many of these health claims, such as helping digestive/gut health and heart health, this may make consumers more sceptical of the category."
McCarthy at Carbery says: "The term 'functional ingredient' is general and can describe everything from vitamins and minerals to proteins, healthy fats and superfruits. While, there may be some scepticism from some consumers, demand for functional beverages is still growing.
"Ingredients such as whey protein, which are backed up by science and EFSA, will carry more weight with consumers and so add value for manufacturers."
A report by Innova in April agreed that protein beverages, "have moved more into the mainstream sports and energy market in recent years, with the development of ready-to-drink products taking the sector away from its traditional format of powder mixes and its target of bodybuilders".
Innova foresees more growth in the sports and energy drinks market, but accepts that justifying health claims remains a challenge. "While physical performance products are widely accepted, the area of mental performance is much more problematic," it says.
"There has been some limited activity in products designed to improve processes such as concentration and memory, but there has been limited success to date, perhaps as a result of ongoing consumer scepticism. The emerging interest in relaxation and alertness drinks that has arisen over the past few years may mark a change in this however, and signal the potential for a whole new market sector designed to help consumers cope with today's stressful lifestyles."
Chaudhari at Fortitech says: "While we do not deal directly with retailers or consumers, I would venture to say that consumers will not make a repeat purchase of a product if it does not live up to its label claims and if they do not see a benefit."
There is, he adds, an even more fundamental issue. "Something can be extremely healthy and deliver on its claims, but if it doesn't taste good, the product is doomed."