The research papers, each published separately, suggest that concerns over levels of caffeine and sugar in energy drinks, and their effects on young people who drink them, are mounting.
The first study - a study of 10-35 year olds Danes’ intake of energy drinks conducted by the National Food Institute of Denmark - shows that when children aged 10-14 consume energy drinks, one in five consumes too much caffeine.
Indeed, when their caffeine intake from other sources such as cola and chocolate is included, every second child, and more than one in three adolescents aged 15-17 consume too much caffeine, said the report.
The Danish report also found that 42% of energy drink consumers have experienced adverse effects such as insomnia, restlessness and heart palpitations.
"It is worrying that so many have experienced adverse effects from drinking energy drinks," said Jeppe Matthiessen, senior adviser from the National Food Institute.
The report also suggests that 10-14 year olds have ‘limited knowledge’ of the ingredients in energy drinks, the side effects of drinking them and the recommendation that children, pregnant women and breastfeeding mothers should not consume energy drinks.
"It seems as if there has been a change in the perception of the types of drinks that people consider normal to drink,” said Matthiessen. “Among younger consumers energy drinks now have the same status as soft drinks had previously.”
“Both the use of and attitudes towards energy drinks give us reason to be concerned that the intake will increase in the coming years and we therefore suggest that more information will be made available about energy drinks aimed at children and adolescents as well as their parents."
Sugar and caffeine?
A second study, published in the Journal of Caffeine Research, adds to the debate on caffeine and energy drinks by evaluating whether the effects of caffeine differ with or without sugar.
The results the research show that the physiological responses to caffeine with and without sugar ‘varied widely’ between individuals.
Elaine Rush and her colleagues from Aukland University measured the heart rate and carbon dioxide production (as a measure of respiration) of individuals for 30 minutes before and after they consumed a defined quantity of sugar, caffeine, or sugar and caffeine.
The team said that the wide range of responses may be due to the effects of caffeine phenotype, physical activity level, habitual intake and metabolic responses, including markers of de novo lipogenesis – adding that further research is needed.