Lately, it's been difficult to pick up a newspaper, watch the TV or scan the Internet without seeing a report about the dangers of drinking soda. As a professor in dietetics, it's often challenging to teach my students how to weed through the overwhelming amount of junk science portrayed in the media. Thus it must be extremely difficult for the average reader to determine the validity and accuracy of these studies and reports. Unfortunately, while much of this "research" is plagued with flawed methodologies hidden in statistical analyses and interpretation, it often produces attention grabbing headlines. But, as responsible readers, we shouldn't draw conclusions or recommendations based on one study, especially those with flawed methodologies.
Recently, I've seen bogus headlines cause confusion and even fear among patients. Several outlets have reported on a recent study published in the Journal of General Internal Medicine that claims drinking diet soda causes heart attacks and strokes. Sounds interesting, but it's just not true.
One of several problems with this study is the wording. Like many studies, the authors noted an "association," between drinking diet soda and cardiovascular events, which many individuals equate to "causation." Nothing can be farther from the truth. Although two variables or items may be associated with each other, it does not mean that one causes or affects the other. For example, it is like saying that being tall is associated with playing basketball; it does not mean that playing basketball makes you tall. Many times you may actually find a statistically significant association between two variables that have no physiological implications or connections. This is the case with diet soda consumption and vascular events.
The next logical question to ask: Exactly how did researchers measure diet soft drink and dietary intake? The answer is: Not accurately. First, it turns out that researchers assessed a person's consumption using a food frequency method; this method has been determined to overestimate food and/or beverage consumption. Further, they only recorded dietary intake at the beginning of a 10-year period, but never again. I am quite certain that any individual's dietary intake will vary greatly over a 10-year span. Some may improve, while others will not, but most will change.
The study's conclusion is extremely flawed. In fact, the authors themselves stated that further research is necessary before any conclusions can be made regarding any health consequences for diet soda drinkers. Yet, we continue to see the news stating that diet soda causes strokes. It is irresponsible to draw conclusions based on inconclusive data, but unfortunately many news reports do not include the necessary information for readers and viewers to determine the difference between solid research and junk science. Instead of alarming individuals with flashy headlines focusing on the villain of the day, it is more important to educate people about nutrition and provide accurate and valid information based on rigorous methodologies.
It's easy to jump on the bandwagon of inflamed science, stemming from agendas seeking to control self-regulation and remove individual choice. It is our obligation and responsibility as scientists, educators, and counselors to provide recommendations based on scientifically sound methods and investigations. We owe it to our fields of study and to those individuals that we serve. When counseling individuals concerned with weight-related issues, I tell my students and clients that diet soft drinks can be part of both a treatment strategy and healthy lifestyle. This view is shared by many healthcare professionals. The safety of diet soda has been well established and has enabled many individuals to reduce their daily caloric intake, lose weight and improve their overall health status. Hopefully, at some point common sense will prevail.