Does diet soda cause diabetes?

Google’s autocomplete suggests common queries and ranks them according to the most searched ones. At number 1 about diet soda: is it good for you.

The answer to that question should be easy, but can it can also become quite philosophical.

The simple answer is clearly “no” – the only good ingredient in diet soda is water, which is very good for you, but water is the basis of any drink, and it comes from the tap, free.

On the other hand, it is perhaps better than some other drinking options, and everything’s healthier than a donut. If diet soda helps people avoid other, more harmful foods and drinks, perhaps it is a step in the right direction and it might have a role in improving health in some specific situations.

The latest on diet soda and diabetes

Soda and other sugary drinks are associated with diabetes. Diabetes affects about 1 in 10 American and is a serious and costly disease. Excess added sugar is an established risk for diabetes, sugary drinks are the leading source of added sugar, and many studies show a clear association between soda consumption and the development of type 2 diabetes. These include randomized controlled studies that showed that sugary drinks aren’t just associated with diabetes – they cause obesity, insulin resistance and chronic inflammation, which are the harbingers of diabetes.

The association between diet soda and type 2 diabetes is a little less clear. Several studies showed a link between drinking diet soda and diabetes, stroke, metabolic syndrome, heart disease and hypertension. These were mostly observational studies, and it’s hard to tease out whether people who have early signs of type 2 diabetes switch to diet soda, or if diet soda indeed contributes to glucose intolerance and diabetes.

When the answer isn’t clear, we await more data.

A new study, just published in the American Journal of Clinical Nutrition followed a group of about 65,000 postmenopausal women. Over more than 8 years 4675 of them developed diabetes.

Both sugary drinks and diet drinks were associated with the development of diabetes.

The more artificially sweetened drinks the women drank the greater their risk of diabetes, and the association stood even when controlled for other risk factors such as obesity.

The risk from diet sodas was however smaller than that associated with regular, caloric soda.

Better than …something

Diet drinks were designed to help people lose weight. Several studies showed an initial weight reduction when people switched from full calorie to non-caloric drinks. Most of these studies were small, short-lived, and sponsored by the beverage industry. Theoretically at least, if you’re a heavy soda drinker, switching to the diet version can help lower your caloric total intake.

But many more studies show that diet drinks are associated with weight gain, and many experts worry that artificial sweeteners are actually fueling the obesity epidemic, perhaps messing with hormonal and metabolic signaling, or changing the gut bacterial population in a detrimental way.

Drinking a lot of sweet drinks – made with sugar or with non-caloric sweeteners – is clearly not healthy. But one can still argue that there are shades of unhealthy, and that the proof tying diet soda with diabetes is weaker than the evidence linking full calorie drinks to this disease.

Maybe a better-phrased question would be “which is worse?”

Dr. Ayala

Full disclosure: I co-founded Herbal Water, where we make organic herb-infused waters that have zero calories and no sugar or artificial ingredients. I’m also a pediatrician and have been promoting good nutrition and healthy lifestyle for many years.