So should we all stop drinking diet soda? Hardly.
First, keep in mind that this study was merely presented at a conference. It has not yet been published, which means that it has not yet gone through the rigorous process of being analyzed by a peer committee for a peer-reviewed publication. It may not make it through this process. Many papers presented at conferences do not.
Secondly, the data are based on one food questionnaire. That’s it. About 2,500 people, part of the Northern Manhattan Study (NOMAS), filled out one food questionnaire about the type of soda they drank, and how often. The researchers reported that they did control for factors such as age, ethnicity, physical activity, calorie consumption, and heart disease history.
But the fact is, all this study told us is that there might be an association between diet soda consumption and stroke risk. It did not demonstrate that diet sodas caused strokes and heart attacks.
There could, for example, be other factors about diet soda drinkers (not taken into account by the researchers) which are far more likely to lead to heart attacks and stroke. Were the diet soda drinkers, for example, also lovers of cheeseburgers and ice cream, full of artery-clogging saturated fat? I personally have a friend who feels so virtuous about the diet drinks she orders for dinner that she regularly splurges on crème brulees for dessert. Literally hundreds of studies published over the past four decades will affirm that it is high-fat, high-sugar, high-calorie-dense foods like cheeseburgers and crème brulees that are killing us, not diet soda.
Finally, in this paper there was no information on the types of soft drinks consumed. There is quite a bit of variability among different brands of diet soda with respect to ingredients, type of artificial sweeteners used, and other additives such as flavorings and colorings.
Interestingly, a separate study using the same data and participants from the NOMAS study evaluated sodium intake. The researchers found that those who consumed more than 4,000 mg of sodium per day had more than double the risk of ischemic stroke than those who consumed less than 1,500 mg of sodium per day.
Why didn’t the media report on this study? These data are far more compelling because they are bolstered by mountains of published scientific evidence supporting the negative effects of salt consumption on cardiovascular and stroke risk. Reporting on this study would have made scientific sense. It would have been responsible. Unfortunately, what we often get from the media, hungry for high ratings, is not responsible. It’s sensational.
If you enjoy diet soda, keep enjoying it, within reason. Once a day, or once or twice a week, as we advise our guests at the Pritikin Longevity Center, is perfectly fine. But far more healthful – and delicious – for all of us with a sweet tooth is nature’s candy – fresh fruit.
And what’s far more important for our cardiovascular health than one paper on diet soda is that we examine all of our lifestyle factors. Dietary habits, exercise, and other lifestyle factors (smoking, alcohol consumption, stress reduction) all play a big part in our overall disease risk.