Your morning coffee may have some unexpected perks. A new study reports it might even help you live longer. But not everybody is convinced, and already controversy is brewing.
This story about a study showing the potential benefits of drinking coffee is fundamentally flawed from the very top, in the way it is presented by both the host and the reporter.
The segment emphasizes a secondary finding the Annals of Internal Medicine study itself states is only suggestive and in need of more proof–that coffee could help you live longer. The host introduces the concept and the reporter amplifies it.
The segment ignores the less sensational but more dependable key finding of the study–that coffee does not appear linked to death by cardiovascular disease, cancer or any cause. The authors suggest consumption at certain levels may have a benefit, but that this study does not have the power to confirm that.
After these missteps, however, the story does a good job of locating this study in the midst of conflicting findings and uncertain conclusions. The reporter takes a skeptical tone and briefly summarizes some benefits and risks of coffee. He draws on two sources, an independent dietician and the American Heart Assocation. Both conclude a couple of cups per day may deliver some benefits and mitigate potential harms. This provides a useful takeaway (at odds with the way the segment begins, but useful nonetheless).
The report also offers the useful takeaway illustrating that a "cup" is much smaller than most people assume. This is an inspired use of a visual medium to educate consumers.
Still: The original sin in the segment’s intro–a compelling conclusion that is not supported by the evidence at hand–can’t be counteracted with solid reporting later on. Consumer confusion is inevitable.
One of the most insightful comments in the segment comes not from an expert or researcher, but from a coffee shop customer: "Yeah but tomorrow there will be another study that shows something negative about this."
The cost of coffee is not an issue in this segment.
Still, an imaginative reporter might have mentioned that 4-6 cups per day can cost from $1 to $9–reason enough for some to refrain from using it for any possible health benefits.
The segment fails to state the core finding of the research–that coffee does not appear to be linked to increased risk of death from cardiovascular disease, cancer or any cause.
Instead it seizes on a secondary finding which the study itself has no power to prove: that coffee "might even help you live longer."
The segment overspecifies when it mentions a 26 percent reduced risk of cardiovascular death among women in the study who drank four to five cups per day. It does not indicate the size of the absolute risk of death–and therefore how meaningful a 26 percent reduction in risk is. See our primer on this topic.
The segment responsibly reports the established links between coffee consumption to sleep disturbance, stress, high blood pressure, and miscarriage.
Through anecdote, it also mentions the possibility of headaches.
The evidence upon which this report is based–a long-term population study which compares self-reports of coffee consumption to deaths from cardiovascular disease, cancer and all causes–is a fine piece of epidemiological research.
But it does not have the power to support the conclusions made in the broadcast segment. The Annals of Internal Medicine study itself makes this absolutely clear.
By selecting a marginal finding and making it the highlight of the story–that coffee "might help you live longer"–the segment generates both false hope and false fear.
Three sources are used:
In addition, the reporter refers to conclusions by the American Heart Association, a quality source to cite for a mainstream audience.
The story would have been stronger if it had interviewed someone involved with the study or an independent researcher on coffee.
Taken as a whole, the segment deserves a "Satisfactory" rating for this criterion.
Since the segment makes claims about the benefits of coffee to reduce risk of heart disease and death, it should have mentioned at least briefly the proven methods of accomplishing the same: weight maintenance, a healthy diet, moderate exercise, and meds as indicated.
Extra points would have been awarded for comparing the benefits of those interventions to the size of the potential benefit coffee might have.
Coffee’s ubiquity is not in question.
As coffee is ubiquitous, its novelty is not in question.
The segment does not appear to draw excessively on a press release.
But perhaps it should have. The press release issued with this study parses the data and conclusions far more carefully than this broadcast segment does.