I’ve written a post or two (or a dozen) discussing science journalism–the good, the bad, and, mostly (because they’re the most fun), the ugly. There was this story about how blondes “evolved to win cavemen’s hearts.” Or this one that completely omitted the name of the pathogen they were writing about. Or this one, where a missing “of” completely changed the results being discussed.
I ran across another glaring example yesterday, dealing interestingly enough with one of my favorite topics: chocolate, and bringing in an “omics” prospective to it.
The news story covered a recent article in the Journal of Proteome Research. The investigators grouped study subjects according to their answers on a diet questionnaire, labeling them either “chocolate desiring” or “chocolate indifferent.” They then fed them either bread or chocolate on day 2 of the experiment, sampled blood and urine, switched the food they received on day 4, and sampled again.
What they found was that, irrespective of the food they were given (bread or chocolate), the “chocolate indifferent” group had a different “metabonomes” (overall indicators of metabolism) than those who craved chocolate, and they attribute this in large part to potential differences in the microflora of the gut between cravers and those who were more neutral on the chocolate issue. This isn’t that awful surprising; love of chocolate could certainly be one way to differentiate groups of people who have, overall, markedly different dietary habits. Perhaps those who don’t care about chocolate eat less junk food overall, or maybe some are lactose-intolerant and avoid dairy. Either way, it wasn’t established in the study that enjoyment of chocolate was really what gave them their final results.
The authors note in their discussion that:
Our observations demonstrate imprinted differences in the gut microbiotal metabolic activities of the individuals that appear to depend on their previous dietary consumption habits…We note that a specific dietary preference appears to influence the functional ecology and biochemistry of the gut in healthy individuals in the sense that excreted metabolites closely reflect the total metabolic activities of the microbiome.
So, diet influences the gut microbiome–again, pretty much expected. Nothing to see here, folks, move along…right?
Until you get to the news story, with a headline that turns the study’s findings on its head, proclaiming that it’s the bacteria that determine your chocolate craving, not the chocolate cravings that determine the composition of the gut ecology.
I know, I know, the journalist probably didn’t write the headline. Nor did they likely add the picture of the woman seductively eating a square of chocolate, with the caption “maybe it’s not your fault after all.”
So let’s look at the story. It does note (way at the bottom) that
…the research did not determine if the bacteria cause the craving or if, early in life, people’s diet changes their bacteria, which then reinforces their food choices.
Sensical, even! Things are looking up, right? Um….
J Bruce German, a professor of food chemistry at the University of California Davis, said the Kochhar research made so much sense that people should have thought of it earlier.
Where did this come from? Which part of the research is he referring to? There isn’t much here that’s all that original, so the “people should have thought of it earlier” comment is just odd and out of place. The original paper was OK, but the oddly thrown-together news story on the research makes this one go down as yet another disaster in science reporting.
Rezzi et al. 2007. Human metabolic phenotypes link directly to specific dietary preferences in individuals. Journal of Proteome Research. 6:4469-77. Link
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