Diet Soda, the Silent Killer?

Vintage diet sodas from the '60s and '70s<a href="http://www.flickr.com/photos/roadsidepictures/2557738266/">Roadsidepictures</a>/Flickr

For indispensable reporting on the coronavirus crisis and more, subscribe to Mother Jones' newsletters.


What is this thing called diet soda? Here are the ingredients of one of the best-selling brands, Diet Pepsi:

CARBONATED WATER, CARAMEL COLOR, ASPARTAME, PHOSPHORIC ACID, POTASSIUM BENZOATE (PRESERVES FRESHNESS), CAFFEINE, CITRIC ACID, NATURAL FLAVOR

My favorite line on that list is the “preserves freshness” that follows potassium benzoate. The freshness of what, precisely? The caramel color? Not likely—caramel color for most colas comes from a chemical reaction between sugar, ammonia, and sulfites at high temperatures. Or maybe it’s the phosphoric acid? Or the least plentiful ingredient of all, the unspecified “natural flavor”? In plain English, diet soda is artificially blackened water tarted up with synthetic chemicals. That anyone ponies up cash for such a thing surely counts as one of the food industry’s greatest marketing triumphs.

But it’s relatively benign, because it doesn’t fill people up with superfluous and potentially toxic calories from isolated sugars. Right? Well, maybe not.

Back in 1990, the National Institutes of Health began funding a long-term study of stroke and cardiovascular risk factors among of urban adults. Known as the Northern Manhattan Study and housed at Columbia University, the project enrolled thousands of people from the community and subjected them to medical testing while recording their food consumption habits.

Among its results, a surprising one has emerged (recently published paper available here): People who drink at least one diet soda a day are 43 percent more likely to experience a “vascular event”—i.e., strokes and heart attacks—than people who drink none.

Now, it’s important to understand that studies like this one establish correlation, not causation. It’s possible that the heart trouble experienced by diet soda drinkers comes from some other behavior they share that has nothing to do with diet soda.

But crucially, this study accounted for factors like weight, diabetes, high blood pressure, and intake of calories, cholesterol, and sodium, study author and University of Miami epidemiologist Hannah Gardener told me in a phone conversation. In other words, nonoverweight diet soda drinkers showed significantly more risk of heart attack than nonoverweight people who don’t drink diet soda.

The Manhattan results comes on the heels of other highly suggestive research showing an association between diet-soda consumption and type 2 (adult onset) diabetes and metabolic syndrome, a condition characterized by abdominal obesity, high blood pressure, and other factors.

I would be remiss if I did not add that the main sweetener for diet soda is aspartame, a substance that back in the early 1980s took a controversial and colorful path through FDA regulatory approval that I described in this Grist post last year. In a 2005 study of rats published in Environmental Health Perspectives, researchers at the European Ramazzini Foundation found aspartame to have carcinogenic effects at low levels—a suspicion that has haunted the sweetener since its tortured approval process in the ’80s. The FDA officially dismissed the Ramazzini results in 2007, claiming that they’re based on poor science.

Even so, the latest research from Manhattan suggests people looking for healthy alternatives to sugary sodas might do well to avoid the “diet” option.

Thank you!

We didn't know what to expect when we told you we needed to raise $400,000 before our fiscal year closed on June 30, and we're thrilled to report that our incredible community of readers contributed some $415,000 to help us keep charging as hard as we can during this crazy year.

You just sent an incredible message: that quality journalism doesn't have to answer to advertisers, billionaires, or hedge funds; that newsrooms can eke out an existence thanks primarily to the generosity of its readers. That's so powerful. Especially during what's been called a "media extinction event" when those looking to make a profit from the news pull back, the Mother Jones community steps in.

The months and years ahead won't be easy. Far from it. But there's no one we'd rather face the big challenges with than you, our committed and passionate readers, and our team of fearless reporters who show up every day.

Thank you!

We didn't know what to expect when we told you we needed to raise $400,000 before our fiscal year closed on June 30, and we're thrilled to report that our incredible community of readers contributed some $415,000 to help us keep charging as hard as we can during this crazy year.

You just sent an incredible message: that quality journalism doesn't have to answer to advertisers, billionaires, or hedge funds; that newsrooms can eke out an existence thanks primarily to the generosity of its readers. That's so powerful. Especially during what's been called a "media extinction event" when those looking to make a profit from the news pull back, the Mother Jones community steps in.

The months and years ahead won't be easy. Far from it. But there's no one we'd rather face the big challenges with than you, our committed and passionate readers, and our team of fearless reporters who show up every day.

We Recommend

Latest

Sign up for our newsletters

Subscribe and we'll send Mother Jones straight to your inbox.

Get our award-winning magazine

Save big on a full year of investigations, ideas, and insights.

Subscribe

Support our journalism

Help Mother Jones' reporters dig deep with a tax-deductible donation.

Donate

We have a new comment system! We are now using Coral, from Vox Media, for comments on all new articles. We'd love your feedback.