Do sweetened drinks deserve a higher tax?

The WHO found those with a high intake of sugar-sweetened drinks were 50% to 60% more likely to be obese.

THE debate about whether tax should be increased on sugar-sweetened drinks hit the headlines again in the run-up to last week’s budget. This is a contentious issue and raises a number of key discussion points.

Firstly, we need to critically evaluate the science in this area and determine whether the adverse health effects attributed to sugar-sweetened drinks are backed up by strong evidence. While there are some studies which have failed to link high intake of sugary drinks with an increased risk of obesity, there are many more which have shown an association. Most notable among these are two studies published this year, one commissioned by the WHO and one conducted by researchers from Stanford University and UCLA.

The WHO paper found those with a high intake of sugar-sweetened drinks were 50%to 60% more likely to be obese than those with the lowest consumption levels. The Stanford and UCLA study showed a significant rise in the prevalence of diabetes among populations with high sugar-sweetened beverage intake. The diabetes prevalence receded as intakes fell.

While this evidence seems compelling, other research has been cited to support the view that these drinks are harmless. However, this body of evidence appears much less robust. For instance, many of these studies simply state that an association between high consumption of sugary drinks and increased risk of obesity and diabetes is not evident from their analyses. This calls to mind the old adage that “absence of proof does not mean proof of absence”. The point is illustrated by the recent emergence of findings from larger, better designed studies which have clearly implicated sugar-sweetened drinks as a potent predictor of obesity. So on balance, it seems that the evidence linking high sugar-sweetened drink consumption with obesity and diabetes is strong.

The next issue is whether the adverse health effects associated with the very high sugary drink intakes observed in the US are applicable to Ireland. While it’s true to say that average US intakes per capita are much higher than here, this does not mean there aren’t sub-groups in the Irish population where very high intakes prevail.

For example, young women from poorer backgrounds consume much greater quantities of sugar-sweetened drinks than their more affluent peers, and also have far higher rates of obesity. Although there are other issues at play here, this finding suggests that high sugary-drink consumption may be at least part of the problem.

The third question is whether a tax on these sugary drinks will deter people from consuming them and whether this will yield meaningful cuts in our obesity rates. A Health Impact Assessment commissioned by the Department of Health in 2012 estimated that a 10% tax on sugar-sweetened drinks would reduce the number of obese adults in Ireland by 10,000. While this would be very welcome, many health professionals argue the full benefit of this initiative can only be realised if the revenue is channelled into obesity prevention and treatment programmes, especially those which cater for vulnerable, high-risk groups.

This aspiration seems logical, but such ring-fencing of tax revenue is rarely, if ever, embraced by the Department of Finance, perhaps limiting the overall public health impact of the proposed tax measure.

Finally, we need to consider this tax in context. The research cited above clearly indicates the potential public health benefits of a tax on sugary drinks, and suggests the Government’s failure to introduce such a measure in the budget is a serious missed opportunity. However, it’s also important to acknowledge that public policy can’t do it all, and consumers have a role to play.

The manufacturers of sugar-sweetened drinks are interested in making profit. By switching en masse to non-sugar sweetened drinks, we have the power to influence these companies, and steer their product portfolios in a healthier direction.

*Dr Daniel McCartney, Lecturer in Human Nutrition & Dietetics at DIT