Put Down That Soda

A study led by Tufts researchers finds that sugary drinks are responsible for 184,000 deaths worldwide each year

a scene in Tanzania of a local shop with soda pop

Soda is as American as baseball and apple pie, but it’s not just Americans anymore who think they are the real thing. Thanks to glamorous ad campaigns and sometimes the lack of clean municipal water, soda pop, sports drinks and other sugary beverages have become the refreshment of choice in much of the world.

The result? Ever higher rates of diabetes, obesity and cardiovascular disease, enough to result in an extra 184,000 deaths per year globally, according to research by Dariush Mozaffarian, dean of the Friedman School, and his colleagues.

Tufts Now asked Mozaffarian about the study, recently published in the journal Circulation and led by Gita Singh, a research assistant professor at the Friedman School.

Tufts Now: Why target sugar-sweetened beverages specifically?

Dariush Mozaffarian: We showed that 184,000 deaths per year in the world were attributable to sugar-sweetened beverages, due to diabetes and other obesity-related diseases. Since this is a single food category without any health benefit, it is a natural thing to eliminate from our diets.

Other efforts to improve health, like lowering sodium or decreasing added sugar, are all feasible, but complicated. You’d need to have replacements, you’d have to think about taste or safety, and so on. But sugar-sweetened beverages can simply be cut out and replaced with seltzer or water or milk. It’s ironically a so-called low-hanging fruit for nutrition and public health policy.

Of course, this is just one part of the food supply, and eliminating sugar-sweetened beverages will not eliminate all diet-related illnesses or obesity. It will have an important impact, but won’t be a magic bullet that’s going to solve all diet-related problems. Yet this is a simple and straightforward first step.

What are some of your most striking findings?

“We are all subsidizing these drinks, and we’re not calculating their true cost to society,” says Dariush Mozaffarian. Photo: Kelvin Ma“We are all subsidizing these drinks, and we’re not calculating their true cost to society,” says Dariush Mozaffarian. Photo: Kelvin Ma
The remarkably high rates of disease related to sugar-sweetened beverages in Latin America and the Caribbean were striking. We identified very high rates of sugar-sweetened beverage intake, obesity and diabetes in those countries which, when taken together, add up to substantial rates of preventable disease.

Another important finding was the very high proportion of obesity- and diabetes-related deaths attributable to sugar-sweetened beverages among younger people—under age 45—in many countries. In the U.S., for example, about 10 percent of all obesity- and diabetes-related deaths under age 45 were attributed to sugar-sweetened beverage consumption. That’s a remarkably high proportion.  

We also found a strong inverse relationship between age and sugar-sweetened beverage consumption. Today in much of the world, people over age 60 don’t drink much sugar-sweetened beverages. Younger people, on the other hand, drink much higher levels than older people. If younger people continue to consume at these high levels as they age, the disease burden due to sugar-sweetened beverages is going to increase dramatically.

Your study talks about not just the health burden but the economic burden of sugar-sweetened beverages. How do they cost nations money?  

People often talk about healthier food costing more. In earlier research published in the British Medical Journal in 2013, we showed that very healthy diets cost, on average, about $1.50 more per person per day than very unhealthy diets. For many Americans, that’s not a large amount; although for poor populations, it can be quite significant.

But what the public and policy makers often don’t think about is the extra health and life costs of poor diets—what we’re paying to doctors, to hospitals, to drug companies to cover the disease burden.  There are also the costs of lost productivity when people can’t work due to disability or illness, and of the lost investments that companies and governments can’t make for other priorities, because they are spending money on diet-related health care. Adding all these costs together, sugar-sweetened beverages produce an enormous economic toll.  We are all subsidizing these drinks, and we’re not calculating their true cost to society.

How did your team come up with the estimated mortality due to sugar-sweetened beverages?

Our analysis is similar to the types of complex modeling used to estimate deaths due to smoking each year, strokes due to high blood pressure and so on.  We obtained the best available global information on all the relevant inputs to this type of estimation.  Importantly, this was not an “ecologic” analysis: we did not simply run correlations of where people are consuming these drinks and where disease is occurring, because such research would be confounded [biased] by many other differences between populations.

First, we determined the levels of sugar-sweetened beverage intake around the world, by country, age, sex and time. Next, we obtained other evidence from long-term observational studies, supported by clinical trials, about how sugar-sweetened beverage intake relates to obesity and diabetes. Then we evaluated the obesity and diabetes rates in all countries, by age and sex.  All these inputs went into a complex model to determine the number of preventable deaths if people didn’t drink sugar-sweetened beverages. 

These types of analyses are crucial to understand what types of policies should be put in place, and where.

What kinds of policies do you think might curb sugar-sweetened beverage consumption?

In follow-up studies, we are looking at the potential impact of specific policies to reduce sugar-sweetened beverages within and outside the United States. For example, we are evaluating and comparing the potential effects of taxation, school- and work-based programs and education to reduce sugar-sweetened beverage consumption. We plan to look at these policies alone and in combination to provide the best information to help inform policymakers as to what should be done.

Mexico, for instance, recently passed a national tax on sugar-sweetened beverages. They are the first country in the world to do so, and many other countries are now considering similar taxes. These types of efforts will give us even more evidence on large-scale policies.

Sugar-sweetened beverage consumption is lower in the richest countries compared with middle-income countries. Why would that be the case?

A lot of sugar-sweetened beverage consumption remains in the United States and other wealthy nations, but it’s also going down for the first time in history.  In high-income countries, people are starting to hear the message about sugar-sweetened beverages, although there’s still a long way to go.

In low-income and especially middle-income countries, these drinks continue to be heavily marketed. These promotions present sugar-sweetened beverages as something that’s desirable, marketed by world-famous musicians and athletes. These famous folks are promoting something that’s harmful, especially for children. We need a real cultural shift here. Would these people promote cigarettes to kids? I doubt it, and they shouldn’t promote sugar-sweetened beverages, either.

Jacqueline Mitchell can be reached at jacqueline.mitchell@tufts.edu.

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