Does Drinking Soda Really Increase Risk of Death?

Soda and other sugary drinks may be linked to an increase in early death, according to a new study from Harvard University. Researchers collected dietary information from more than 100,000 health professionals and found that, the more sugary beverages they consumed per week, the more likely they were to die during the study period.

“These findings are consistent with the known adverse effects of high sugar intake on metabolic risk factors and the strong evidence that drinking sugar-sweetened beverages increases the risk of type 2 diabetes, itself a major risk factor for premature death,” said coauthor on the study Walter Willett in a statement, adding that soda taxes make sense “because the current price of sugary beverages does not include the high costs of treating the consequences.”

Willett is right. There is ample evidence that sugary beverages such as soda and juice are public health menaces. This isn’t even the first study to find that soda is linked to mortality in general—one 2015 paper attributed 184,000 deaths per year to sugar-sweetened drinks. The American Academy of Pediatrics recommends that children consume no more than six teaspoons of added sugar per day, and only one sugar-sweetened beverage per week.

Whether sugar is good for you, or your kids, really is not a matter of scientific debate. It’s bad.

This new study cast a spotlight on the problem, and found that more soda led to more problems. Drinking between two and six sugary beverages per week increased the overall risk of death by six percent. One drink per day increased the risk by 14 percent; two or more by 21 percent. Regular diet soda consumption appeared to be less lethal—artificially sweetened beverages were linked to a mere four percent increased mortality.

But while the Harvard soda study is well-designed and robust, it is important to note that the research is not quite the slam dunk that it appears to be. There are all of the usual caveats: correlation is not causation, the soda consumption was self-reported and thus not necessarily reliable, virtually the entire sample consisted of homogenous white, wealthy, healthy professionals. But then, there’s also the simple reality check. How much, exactly, is a six percent (or, for that matter, 21 percent) increase in risk of death, among a healthy population?

Not very much. This study included participants between the ages of 35 and 75, when the risk of death for the general population is about 1 in 358, or 0.28 percent (women have much lower death rates than men, and those above the age of 40 skew the data, but this is the average figure). A six percent increased risk would bump that up to 0.29 percent, or about 1 in 340. Even a 21 percent increased risk only changes the overall risk of death from 0.28 percent to 0.34 percent, or about 1 in 300. So while it is true that sugary drinks appear to be correlated with an increased risk of death within a specific population, that 21 percent figure sounds a lot scarier than it actually is.

None of this is to say that we shouldn’t limit our sugar intake. Parents should cut back on sugar and excise it from their children’s diets whenever possible. But the occasional Coca Cola isn’t killing anyone, and there’s no need to be alarmed by murderous soda pop. As a rule, “21 percent increased mortality” is seldom as lethal as it sounds. This study is no exception. So, as is often the case, the scientific advice matches the simple, logical advice:

Everything in moderation.