A coordinated cultural war is being waged against soft drinks. A Washington Post headline read: “Research suggests kids who drink a lot of soft drinks risk becoming fat, weak-boned, cavity-prone and caffeine-addicted.” The Post-Dispatch said, “Sodas increase kids’ risk of obesity, study reports.” The effort to denormalize fizzy beverages generally emphasizes four flawed arguments.
Harvard researcher David Ludwig’s study in the British medical journal The Lancet claimed to connect soda drinking to obesity. However, a Lancet editorial observed that “a large proportion of the children (in Ludwig’s study) were obese” to begin with, which, the Lancet points out, certainly affected the study’s outcome.
Ludwig himself wrote “there is no clear evidence that consumption of sugar per se affects food intake in a unique manner or causes obesity.” The obvious flaws in Ludwig’s research also earned this response from the U.S. Centers for Disease Control and Prevention: “There are no data from the Harvard study that allow us to make an estimate of what proportion of obesity might be accounted for by changes in soft drink consumption.”
The baseless contention that soft drink leads to caffeine dependence in kids depends entirely on the work of anti-soda activist Roland Griffiths. His research was designed to show that the popularity of caffeinated soft drinks comes from “the mood-altering and physical dependence of caffeine.”
Alan Leshner, director of the National Institute of Drug Abuse (which funded Griffiths’ research) argues this, noting that Griffiths’ study included only 25 subjects, too few to allow real scientific conclusions. An earlier study by Griffiths was criticized by the International Food Information Council for trying to demonstrate caffeine addiction using a “sample size of only seven subjects,” himself and six fellow researchers.
As for soft drink consumption causing tooth decay: In the United States, cavities have been on the decline among children at the same time their soda consumption has increased. Still, the Ohio Dental Association cautions that “acid begins to dissolve tooth enamel in only 20 minutes.” So, swallow before 20 minutes are up — and brush.
The myth that soft drinks can deplete bones of calcium lives on in the work of Harvard public health researcher Grace Wyshak. Last year, her study concluding that “girls who drank cola were about five times more likely to suffer bone fractures.” Imagine what she might have written if she had actually measured her young subjects’ bone density (she didn’t), or if the participants had been asked how much soda they drank. (They weren’t.)
In Wyshak’s words: “the (study) design is cross-sectional and causality cannot be inferred from the data.” This means her study did not prove her point.