Diet soda-stroke connection needs more research
Friday, July 19, 2019
Q Help me understand the recent news about diet soda and stroke risk. CK, Greenville
A I got lots of questions about the news headlines that screamed “drinking two or more diet beverages a day linked to high risk of stroke, heart attacks!” There often is a difference between the headline that grabs your attention and the details of a study. Niki Winters, a third-year Brody medical student wanted to unpack this study for you. Here is what she wants you to know:
As medical students, we learn that correlation does not equal causation. If there is an association or a link between two factors, like drinking diet sodas and a higher risk of stroke, it does not mean one caused the other. However, it does mean that we should be aware of the link and hope for more research that will lead to confirming or rejecting the observation.
The study that got headlines was called “Artificially Sweetened Beverage and Stroke, Coronary Heath Disease, and All-Cause Mortality in the Women’s Health Initiative.” It was an important and large study, so we should pay attention to it. The researchers followed health outcomes of 81,714 people, mostly white women ages 50 to 79, for almost 12 years. The women who drank more than two artificially sweetened beverages — we will call them diet drinks — a day were described as more likely to be younger, obese, smokers, do little exercise, eat a lower quality diet and have a history of diabetes, heart disease or a heart attack.
You probably know that all these behaviors contribute to poor health outcomes. The researchers concluded that the women who drank more than two diet drinks a day had a 16- to 31-percent higher risk or chance of having a stroke, heart disease or death from any cause. This probability or risk factor is high enough to get our attention, but more work needs to be done before the experts really know if the women described above should avoid diet drinks altogether.
The researchers themselves said that this study was observational — not a clinical trial — meaning that more research can still to be done to better correlate diet drinks with stroke risk. In this most recent study, women answered a survey question of how often do you drink “diet drinks, such as diet Coke or diet fruit drinks?” The researchers said it is possible that the women in the study interpreted this to also mean teas and/or coffees with artificial sweeteners.
In addition, the women in this study also self-reported the quality of their diet, which may not be as accurate as researchers’ measuring their intake. In the future, a research trial that physically measured diet drink intake and diet intake would provide better data than self-reported data and make it easier to know the impact of diet drinks on health.
There have been other studies that have shown a link between drinking more than two servings of artificially sweetened beverages in a day and a 50 percent increase in death from heart disease. Other studies, too, have shown a link between diet drinks and an increased risk for stroke, dementia, heart attacks, and coronary heart disease.
So this recent study — that got these headlines — continues to add and not contradict experts’ observations that consuming large amounts of diet drinks or using lots of artificial sweeteners can lead to several unhealthy outcomes including heart disease, stroke, weight gain, increased fat storage, decreased ability to regulate blood sugar, increased insulin release, change in gut bacteria, and change in taste sensation for sugar.
For now, it is best to be aware of the link between artificially sweetened products and an increased risk of adverse health outcomes. We would encourage everyone to drink more water. Always check nutrition labels for added sugars and chose options that are lower in sugar. Since there are so many behaviors that contribute to stroke and heart disease, we can’t say which is most important.
We would encourage everyone to treat or manage their risk factors, including high blood pressure, diabetes, known heart disease and excess body weight. If using diet drinks and artificial sweeteners helps a person do that, it may be the best choice for her.
And of course, always ask your family doctor about your risks for different health conditions and the best way to manage them. If you have any further questions about the study, you may want to read the original research paper published earlier this year in STROKE. You can access it for free at https://www.ahajournals.org/doi/10.1161/STROKEAHA.118.023100.
Professor emeritus Kathy Kolasa, a registered dietitian nutritionist and Ph.D., is an affiliate professor in the Brody School of Medicine at ECU. Contact her at email@example.com.