If you watched or read the news last week, you probably saw alarming headlines like “Research Links Diet Soda to Dementia”(Science Times), “Diet Soda Can Increase Your Risk of Dementia” (USA Today), or my personal favorite “Will Diet Soda Kill You or at Least Give you Dementia” from the Bangor Daily News. I love a little hyperbole in the morning.
Splashy headlines (pun intended) get clicks.
A Closer Look
The study, published in the American Heart Association’s Journal Stroke analyzed data from 4000 participants in the Framingham Heart Study Offspring cohort. The study relied on the self-reported intake of diet soda utilizing a Food Frequency Questionnaires (asking people to recall what they have eaten in past days, months, or years).
What researchers found is that those who drank at least one diet soda/artificially sweetened beverage a day were nearly three times as likely to develop Alzheimer’s dementia or stroke over a ten year period than people who didn’t drink the sweet stuff.
So if I Don’t Stop Diet Soda Now, I’m Definitely Going to Have a Stroke.
Not really. First of all, the “triple” warnings of the risk of dementia and stroke aren’t quite as alarming when you think about the absolute risk of these conditions. For example, in this study, just 3% of people had a stroke, and 5% got dementia. That means 97% and 95% didn't get either condition.
Ok, So I Might Not Have A Stroke, But It Still Sounds Scary.
The results found a correlation between diet soda consumption and stroke/dementia. Correlations are common findings in research—one thing happens, and another thing happens. That’s all. Even the researchers themselves admit that they can’t draw any cause and effect from this study and that more research is needed. So what other factors may have played a role in this study? The authors controlled for many risk factors, including smoking, age, and diet. However, what they didn’t control for was diabetes and vascular risk factors (both risk factors for stroke and dementia). When those variables were put into the data, the risks were no longer significant
Which Came First...the Chicken or the Soda?
The study authors state that because of the observational nature of their study, they could not determine whether it was the diet soda or if people with diabetes were more likely to utilize it as a beverage. So was it diabetes? Or the diet soda? Or some combination of both? This study could not determine that.
Some limitations of this study:
This study was primarily conducted using Caucasian participants of non-European descent. There were very few ethnic minorities in the study.
There was no examination of other things that may increase the risks. Did the participants abuse drugs? Did they have a family history of stroke or dementia?
There was no examination of exactly which artificial sweetener was the most problematic. Was it Aspartame, Saccharin, Splenda, or Stevia? Who knows?
The researchers relied on self-report of intake. I don’t know about you, but I have a difficult time remembering what I ate yesterday, let alone last week, or last year. The participants didn’t keep a detailed food diary for researchers—they relied solely on participant recall of what they had eaten.
Ok, so what should I do?
I can’t tell you what to do, but here’s what I’m going to do. I’m not going to panic, and I likely won’t stop drinking a daily Diet Coke. I will try to drink more water, but that’s just a good thing to do and has nothing to do with the results of this study. What I'm NOT going to do is switch to regular Coke.
Multiple studies have found links between sugar-sweetened beverages and health problems.
I will also keep my eyes open for a Randomized Control Trial (RCT) which is the gold standard of research, on the subject. There needs to be a study group, a control group, and defined periods of time and exact amounts of diet soda. All variables (including diabetes) need to be controlled.