The findings from the population-based study are clear - those who reported drinking diet soda daily were more likely to have a cardiovascular event (stroke or heart attack).
However, the study is only preliminary, and has been published as an abstract, not as a piece in a peer-reviewed journal. The researchers' methodology has been called into question, on several grounds.
* They used data from a study carried out by questionnaire where participants were only asked about their soda intake at the start of the study period.
* The scientists failed to take into account some factors like family history of cardiovascular disease, and variations in eating habits.
* The numbers of people involved are relatively small.
* The study population had an average age of 69; older people are naturally at more risk of stroke.
Due to the small sample size, it's possible that the results simply show natural variation, as ABC news points out:
The study population may have been at a higher-than-normal risk for cardiovascular events, with an event rate of 22 percent compared with the expected rate of 8 to 10 percent.
Many nutritionists and other experts have suggested that diet soda drinkers are more likely than regular soda drinkers to be overweight, or to have diabetes.
Jennifer Cleary from the Lipid Disorders and Metabolic Syndrome Clinic at Northwestern Memorial Hospital in Chicago, was quoted in the Clinical Advisor saying:
There are a lot of factors that were not taken into consideration, so we can't really assume that there is a causal relationship between diet soda and stroke. [...] [People drinking diet soda] might also be consuming fast food and making other unhealthy lifestyle choices.
It looks like there's no strong evidence in this research - the results could be explained by statistical chance, or by factors which weren't accounted for.
Even so, if you're a frequent diet soda drinker, you'll want to make sure you:
* Don't use diet drinks as a way to compensate for a poor diet.
* Try to limit your intake, just as you would with any less-than-healthy food.
* Don't get too hooked on the sweet taste, it can encourage you to eat sugary foods.
