After vilifying sugary soft drinks as one of the main causes of our nation’s obesity epidemic, the media is now going after diet sodas as well by publicizing a thoroughly unscientific, poorly executed study presented yesterday at the American Stroke Association International Stroke Conference in Los Angeles. Researchers used data on 163 people who drink one or more diet sodas per day and found that they had a 61 percent increased risk of cardiovascular events compared to 901 participants who reported drinking no diet soda. Although the study allegedly controlled for the effects of smoking, physical activity, alcohol consumption and calories consumed per day, it failed to control for a family history of cardiovascular disease, hyperlipidemia, and most importantly, body mass index — all of which are factors that would most likely explain the observed increase in heart attack or stroke risk. They failed to even report the subjects’ average weight in the two groups, which could in itself be the explanation.
In addition, nearly three-quarters of the study participants were Hispanic or African American, both of which are minority groups considered to be at higher risk for cardiovascular events, thus further muddling the study results. Moreover, it’s not even clear that the researchers' data on the amount of study subjects’ calorie consumption was reliable or accurate.
Dr. Howard Weintraub, clinical director of the New York University Center for the Prevention of Cardiovascular Disease, offers a more plausible explanation for the findings: “Unfortunately, it may be that individuals with poor dietary habits do resort in some kind of calorie balancing and continue to eat high-calorie sweet foods but reduce their guilt by drinking diet soda.”
Alarmed by how a study rife with so many uncontrolled confounders could be so widely addressed as though factual by the mass media, ACSH’s Dr. Elizabeth Whelan points out that “diet soda is not just one uniform product, but rather is comprised of a variety of formulations that incorporate either Splenda, aspartame or saccharin. Thus, they’re all chemically different and cannot pose the same effect, but the researchers of this study decided to lump them all together, anyway.”
“These researchers completely ignored every precept of solid epidemiological research, and what’s more, they failed to detect an increased risk of cardiovascular risk among daily drinkers of regular soda,” says ACSH’s Dr. Gilbert Ross. “There are absolutely no biological hypotheses that can begin to justify this. I doubt any reputable scientific, peer-reviewed journal will ever publish such nonsense.”