A widely reported study published last week in the journal Stroke found that drinking even one can of diet soda a day triples your risk of dementia. Unsurprisingly, this finding caused quite the uproar but it’s probably not time to throw away your diet soda quite yet.
This is the first study to find a link between artificial sweeteners and dementia, no other study I can find has found any link between the two. As it stands, the evidence that drinking diet soda may contribute to dementia risk is weak, at best. This study simply observed that people who drink diet soda regularly are more likely to eventually be diagnosed with Alzheimer’s disease or dementia.
Essentially spotting some correlation but not at all finding causality, the distinction is important. Here’s why, further analysis found that those who drink diet soda are also more likely to be obese or have diabetes or heart disease. All of these conditions significantly increase your risk of developing Alzheimer’s disease.
Is it at all surprising that people who are overweight or have diabetes or heart disease might be more likely to drink diet soda because they are trying to reduce their sugar or calorie intake? Not at all.
So the real question here is: Did researchers find that drinking diet soda increases your risk of dementia or did they simply once again find that having diabetes or being overweight does?
Sure enough, when the researchers adjusted the analysis to account for these other risk factors, the link between diet soda consumption and dementia essentially disappeared while known risk factors like diabetes remained.
This finding will likely prompt more researchers to ask the same question and complete more thorough studies, which will shed a lot more light on the situation. But, until they take a randomized sample of healthy participants, blind them and control for confounders there’s no reason to put down that diet soda.