Just about every week, it seems, a new study warns of another potential health risk linked to soft drinks.
The most recent headlines have raised concerns that diet sodas boost stroke risk. Diet and regular sodas have both been linked to obesity, kidney damage, and certain cancers. Regular soft drinks have been linked to elevated blood pressure.
Several hundred soda studies have been published over the last two decades, but most of the ones done in humans (as opposed to mice or rats) relied on people’s memories of what they drank.
Observational studies like these can point to possible concerns, but they can't prove that sodas do, or don’t, pose a health risk.
If you drink sodas -- especially if you drink a lot of them -- what are you to make of all the headlines? Do you dismiss them, as the beverage industry does, as bad science and media hype? Or is it time to put the can down and take a hard look at what you're drinking?
In the past six months alone, dozens of studies examining the health impact of drinking sugary beverages or diet soda have been published in medical journals. Some suggested a relationship; others did not.
Sometimes, the media coverage of these studies took the researchers by surprise.
That was the case for epidemiologist Hannah Gardener, PhD, of the University of Miami. In February, she presented early results from her ongoing research at a health conference, and was completely unprepared for the media attention it received.
The story appeared on all the major networks, in most major newspapers, and on the Internet, including WebMD.
The early findings showed a 48% increase in heart attack and stroke risk among daily diet soda drinkers, compared to people who did not drink diet sodas at all or did not drink them every day.
Most reports cautioned that the findings were preliminary and did not prove that diet sodas cause stroke.
But Gardener says many media reports overstated the findings. And even when the stories got it right, she says the headlines often got it wrong by leaving the impression that her research proved the diet soda-stroke connection.
“It was just an abstract presented at a meeting. It hasn’t even been published yet,” Gardener tells WebMD. “We are still working on the analysis. I don’t think the level of press attention it received would have been warranted even if it was a published paper.”
Gardener's team attempted to control for known heart attack and stroke risk factors, such as poor diet and lack of exercise, but she concedes that these factors could have influenced the findings.
Purdue University behavioral sciences professor Susan Swithers. PhD, had a similar experience in 2004, following the publication of her study in rats suggesting that no-calorie sweeteners like those in diet sodas increase appetite.
Swithers says she was shocked by the amount of news coverage her study received.
“Frankly, we were stunned,” she tells WebMD. “It really was a small study.”