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“A spoonful of sugar helps the medicine go down”: Soda tax, public health and the prevention of diabetes

For those of you who missed it, the Speaking of Medicine ran in July a four week special in relation to the PLOS Medicine Special Issue on Preventing Diabetes, which included research and commentary on the global burden of diabetes, taxes on energy-dense foods, the benefits of home-cooked meals, and downstream risk of heart disease. In 2016, researchers specializing in diabetes prevention were guests in two separate PLOS Science Wednesday “Ask Me Anything” chats. First, Dr. Sanjay Basu, a physician and epidemiologist at Stanford University, was an AMA guest in February 2016. In a July 2016 AMA, Nick Wareham, Fumiaki Imamura and Jenna Panter answered questions about their research featured in the PLOS Medicine Special Issue.

This attention on the prevention of diabetes comes as no surprise when overweight, obesity and diabetes is on the rise globally and now constitutes major global public health challenges. The WHO estimates in their recently published Global report on diabetes that 422 million adults around the world were living with diabetes in 2014 and that the global prevalence of diabetes (of all types) had doubled since 1980, rising to 8.5% in the adult population. The prevalence of diabetes reaches almost 10% among American males. Overweight/obesity and physical inactivity are the strongest risk factors for diabetes, as noted by the WHO in the report. One measure being currently discussed to curb the intake of sugar intake and prevent obesity and diabetes is the so called “soda tax” or the Sugar-Sweetened Beverage Taxation (SSB).

Taxation as public health tool

IMG_0410In a research article released in week 1 of the Diabetes Prevention Special Issue, Dr Lindsey Smith Taillie and colleagues evaluated the effectiveness of Mexico’s 8% tax on purchases of non-essential energy-dense foods, which was introduced in January 2014. Interestingly, purchases of high-energy foods were reduced by 5.1% per month after introduction of the tax and the decline was more pronounced in low SES households, which purchased on average 10.2% less taxed foods than expected. A study in the British Medical Journal had previously this year gained similar results, which shows the potential in this kind of taxation to curb obesity and diabetes. As the action began to gain momentum, the WHO Commission on Ending Childhood Obesity (ECHO) released a report earlier this year recommending that governments implement taxation on sugar-sweetened beverages. As discussed in in a blog post in Public Health Perspective earlier this summer, Philadelphia successfully passed a soda tax in June by not only use health argument but also “sell” it as a revenue generator for the city.

To investigate the potential of this kind of taxation to prevent diabetes, Basu modelled the effectiveness of a SSB tax in India and found that, given that SSB sales continue to increase at the current rate a 20% SSB tax would reduce overweight/obesity across India by 3.0% and the incidence of type 2 diabetes by 1.6% over the period 2014–2023. The relative effect of SSB taxes would be expected among both urban and rural populations in India. In 2013, Basu published a cross-sectional study in PLOS ONE showing that differences in sugar availability statistically explain variations in the prevalence rate of diabetes at a population level that cannot be explained by factors such as physical activity, overweight or obesity. These findings indicate a SBB tax could be a valuable public health response to the growing global burden of diabetes.

But research shows that food and beverage industries often oppose this kind of taxation, arguing that the tax will inhibit consumer choice and the free market. A second major argument introduced by the industry is that taxation on SSBs promotes economic inequity and is ineffective by targeting poorer households. According to a new report from Corporate Europe Observatory, trade associations that represent the biggest players in the food and drink industry are derailing sugar regulation policies already in effect in the European Union. In total, the key trade associations, companies and lobby groups behind sugary food and drinks spend almost $24 million annually to lobby the European Union. Sensing an emerging market, multinational processed food manufacturers are specifically targeting potential consumers in low- and middle-income countries (LMICs). This marketing method has led to increased consumption of unhealthy commodities in a short amount of time.

Sugar industry takes a page out of big tobacco’s playbook

Mirroring tobacco industry practices, the sugar industry has tried to avert public health measures aimed at limiting consumption of their products. PLOS Medicine researchers analyzed internal sugar industry documents from 1959 to 1971 to investigate how the industry sought to undermine or subvert policies that aimed to restrict sugar consumption in the US in that time period. The findings also showed the industry tried to influence research priorities for the National Caries Program (NCP) by the US National Institute of Dental Research (NIDR) in 1971. These practices continue to this day; last summer the New York Times reported that Coca-Cola used tactics similar to the tobacco industry to shape the scientific discussion about its products. Coca-Cola funded researchers to promote a new “science-based” solution to the obesity crisis that focused on exercise instead of the intake of calories, thereby acquitting their products from blame for poor health outcomes.

It is well known that corporate funding of nutrition studies works in favor of the companies. A systematic review found that research funded by the sugar industry were five times more likely to find no link between sugary drinks and weight gain than studies whose authors reported no financial conflicts. Without transparency, dietary guidelines risk being tainted and ultimately even hazardous to health.

In 2015 the WHO released a new set of guidelines recommending that adults and children reduce their daily intake of free sugars to less than 10% of their total energy intake. Free sugars refer to monosaccharides (such as glucose, fructose) and disaccharides (such as sucrose or table sugar) added to foods and drinks by the manufacturer, cook or consumer, and sugars naturally present in honey, syrups, fruit juices and fruit juice concentrates. As stipulated in the press release on the guidelines, a further reduction to below 5% or roughly 25 grams (6 teaspoons) per day would provide additional health benefits. In the WHO Global report on diabetes, food producers were identified as important stakeholders to halt the growing global burden of diabetes and improve the lives of those living with diabetes, their rhetoric must now be backed up with the appropriate action and public health policy. Otherwise we are unlikely to achieve SDG 3.4, that aims for one-third reduction in premature mortality from non-communicable disease by 2030. Now is the time to allow public health to take precedence over the concerns of the private sugar industry.


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