Consumption of hot beverages, tea and coffee, are in decline; consumption of bottled water, juices and fizzy drinks are increasing, especially among the under 30s. The National Diet & Nutrition Survey of British adults aged 19 to 64 years showed that young adults consumed more concentrated and carbonated soft drinks and less tea and coffee than adults over 50 years. For example, 92% of men aged 19 to 24 years reported drinking carbonated soft drinks over a 7 day period with average intakes at 2.2 litres, compared to only 33% of men over the age of 50 years, who consumed on average just over 0.7 litres.

A recent niche development within the soft drinks market has been described as ‘energy/stimulant’ drinks. In 2005, the market research company Mintel estimated that these accounted for 20% of the spend on soft drinks, worth more than £1 billion per annum; there is likely to have been an increase in the interim period.

There is advice on the description ‘energy drink’ from the UK Committee of Advertising Practice. However the term is not legally defined within the UK or within EU directives. There is a category of products defined as ‘foods intended to meet the expenditure of intense muscular effort, especially for sportsmen and sports women’ under the ‘foodstuffs for particular nutritional uses’ (PARNUTS) directive. In some specific situations, sports drinks are helpful: they are formulated to support rapid rehydration where time for fluid replacement is limited, and rates of body water loss are high due to muscular exertion and heat. In less intense situations, for most people most of the time, ordinary fluids, and best of all tap water, are fully adequate.

So what are energy drinks? The body’s energy supply is derived from nutrients (mainly carbohydrate, fat and protein); the unit of energy measurement is the kilocalorie (kcal) or the kilojoule (kJ). All foods provide some energy, and amounts will depend on the types and amounts of nutrients they contain. A drink containing energy would be any drink containing a nutrient, however the most effective form to increase levels of blood sugar quickly would be a drink containing sugar (glucose).

Energy can also mean ‘the perception of vigour/vitality’. Caffeine is a well-known and well-described ingredient with stimulant properties: moderate amounts benefit mood and mental alertness in many people. Energy drinks usually contain higher amount of caffeine per 100ml than standard cola drinks, but intakes per portion are modest because unit sizes of the ‘bullet’ cans (250ml) are smaller than standard size soft drink cans (330ml). Intakes of caffeine per unit of energy drink are about the same as found in a cup of coffee. There are other ‘stimulant’ ingredients popular in energy drinks e.g. guarana which contains guaranine, a component nearly identical to caffeine, and taurine. Taurine is a non-essential amino acid found in protein foods such as meat and fish. Some studies show that isolated supplements of the amino acid taurine can reduce exercise-induced markers of oxidative stress in muscles. Little is known about the general effects of consuming taurine, other than that levels in stimulant drinks are higher than that of the rest of the diet.
These other substances are less researched, but their effects are not likely to exceed those documented for caffeine.

So energy drinks contain sugar/glucose, caffeine, and possibly some other ingredients with mild stimulant properties; whether they support feelings of vigour and alertness greater than the modest effects of ‘a cup of coffee and a biscuit’ remains to be proven.

The information was correct at issue. For personal dietary information, a local dietitian is the best source of information. Want to be sure the dietitian you consult is registered? Check the Health Professions Council search facility of dietitians registered in the UK (www.hpc-uk.org)

Issue date: April 2007