To Freak Out or Not to Freak Out? Diet Soda Edition
Posted on Wednesday, May 3rd, 2017
There’s nothing quite like a Daily Mail headline to freak you out:
Naturally, there were those who felt the need to respond.
But while the article below it correctly points out the limitations of the study in question (more on this in a sec’), headlines like that can make it sound as if the research itself was bunk. And not a lot of people will read beyond that.
But we have to admit, that’s a sexier headline than “Study Shows Association Between Diet Soda Consumption, Stroke, and Dementia.”
And that’s all that the study in Stroke actually showed. Those who drank more diet soda showed a higher risk for the two conditions. It didn’t show that diet soda caused them. An observational study can’t show that.
There were other important limitations, too. For instance, the results came from an ethnically homogenous group. The researchers didn’t account for other sources of artificial sweeteners in the diet.
On top of that, the three-fold risk that the Mail shouted about? That was relative risk. The overall risk was still on the low side.
“Even if someone is three times as likely to develop stroke or dementia, it is by no means a certain fate,” [lead author Matthew] Pase said. “In our study, three percent of the people had a new stroke and five percent developed dementia, so we’re still talking about a small number of people developing either stroke or dementia.”
So go ahead and drink your diet soda?
Just as a single observational study can’t tell you that it’s harmful, it also can’t tell you that it’s perfectly benign.
But plenty of other research through the years suggests that it’s not something you want to drink a lot of. Some research has shown that regular consumption of diet soda reduces microbial diversity in the gut, which has significant implications for metabolic and mental health in particular. And we’ve known for years that it can damage teeth just as readily as the sugary stuff it’s meant to replace.
And then, of course, there are the familiar concerns with the artificial sweeteners themselves.
Interestingly, the authors published another paper recently that seems to have received much less attention, maybe because it confirms so much of what we already know.
This companion study, published in Alzheimer’s & Dementia, looked at the possible relationship between drinking sugary beverages and developing early signs of Alzheimer’s.
The researchers looked at people who consumed more than two sugary drinks a day of any type – soda, fruit juice, and other soft drinks – or more than three per week of soda alone. Among that “high intake” group, they found multiple signs of accelerated brain aging, including smaller overall brain volume, poorer episodic memory, and a shrunken hippocampus, all risk factors for early-stage Alzheimer’s disease. Researchers also found that higher intake of diet soda – at least one per day – was associated with smaller brain volume.
Again, we have association, not causation. But considering the wealth of research to date, both of these studies suggest yet more reason to make soda a sometime or never thing, not a habit.
Image by Mike Mozart, via Flickr