Australasian Science: Australia's authority on science since 1938

Do Soft Drinks Lead to Teen Violence?

By AusSMC (ed.)

A study published in Injury Prevention suggests a link between high fizzy soft drink consumption and violence among teenagers, but how strong is the evidence?

“These findings probably tell us more about the people who drink large volumes of soft drink rather than necessarily suggesting a causal link between soft drink and anti-social behaviour. The study really cries out for more research to understand why heavy use of soft drink may be an indicator of poor behaviour and what are the social conditions that lead to such heavy use. Such a study would also need to look at the impact of alcohol, caffeinated drinks and illicit drugs, which we do know have both an indicator and a causal link.”
Michael Moore is CEO of the Public Health Association of Australia

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“This is an interesting report, but I would suggest an exceptional degree of caution in interpreting the findings. It shows that a lot of young people involved in aggressive behaviour drink soft drinks, but it is hard to draw any further conclusions at this stage. There would undoubtedly be great health benefits in reducing soft drink consumption in young people and the wider community.”
Mike Daube is Professor of Health Policy at Curtin University

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“I find this a particularly interesting paper that, as the authors rightly state, looks at an association that is rarely considered regarding teenage aggression. The large sample size gained for the study also adds weight to their findings.

“A big limitation, and one acknowledged by the authors, is the lack of information regarding the dietary habits of these students. It would have been very interesting to examine their overall dietary practices, particularly given the results of a recent Australian study (Oddy et al., 2009) which found that teenagers with a western diet (higher consumption of food containing saturated fats and sugars) were much more likely to show indications of behavioural problems and symptoms that may have been indicative of a propensity for psychological disorder.

“There is very little research that looks at the impact of long-term consumption of drinks containing high levels of caffeine, sugar and artificial additives (e.g. preservative sodium benzoate and artificial colourings) on mental health. Physically we know that high consumption is associated with obesity, diabetes and heart disease, but the jury is still out regarding the psychological implications of this level of regular consumption.

“The message to take away is really ‘everything in moderation’. As humans we were not made to consume these drinks on a regular day-to-day basis. Physiologically they can have devastating effects on our bodies in a physical sense. It's not hard to believe that they may have similar effects on our brain chemistry in large, long-term doses, especially amongst teenagers whose brains are still growing, developing and changing in response to their environments.”
Dr Karena Burke is a Senior Lecturer in Psychology at the School of Health and Human Services, Central Queensland University

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“As the authors themselves rightly caution, there may be other factors that they have been unable to account for that lead to both high soft drink consumption and aggression in young people, so it is difficult to draw any definitive conclusions from this study on its own. However, it does suggest that a trial of an intervention to reduce high soft drink consumption may be worth considering in high risk populations, and may lead to broader health benefits beyond reducing aggression.”
Dr Seena Fazel is Senior Lecturer in Forensic Psychiatry at the University of Oxford, UK

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“The causes of violence in young people are complicated, and this work is presenting an overly simplistic interpretation of the role of ‘soft’ drinks. There are a large number of known risk factors that would contribute to violent behaviour that have nothing to do with the consumption of these drinks.

“We know, in many areas of human behaviour, that correlation does not imply causation. We also know that poor diet is associated with a range of negative health and social outcomes.

“This study is unsurprising. But, more importantly, it fails to address ‘third-variable’ issues that could explain the findings. Kids exposed to different social, parental or educational backgrounds might therefore have different diets and different attitudes to aggression, without any direct causal link.

“As the authors themselves say, ‘there may be other factors, unaccounted for in our analyses, that cause both high soft drink consumption and aggression’. That's true, and renders this study rather limited I'm afraid (especially because that outcome could easily have been predicted).

“A laboratory study of the impact of such drinks on aggression and violent behaviour is very feasible and ultimately far more informative.”
Prof Peter Kinderman is Professor of Clinical Psychology at the University of Liverpool, UK

Source: AusSMC