We’re drowning in hyped-up latest-research health stories. From “dark chocolate lowers blood pressure” to “blueberries help prevent Alzheimer’s” and “overweight people live longer,” the Internet presents a constant stream of health news that, if we listened to it all, might have us gorging on chocolate topped with berries.
And that could be a problem, because if you read closely, you’ll find that certain types of studies don’t show real evidence of a health benefit.
Don’t Mistake Association for Cause and Effect
The recent study suggesting that overweight people live longer was based on an analysis of more than 100 studies and published by the respected Journal of the American Medical Association in January. The study included over three million people. But it only compared body mass index (BMI) and dying of any cause. So all it could produce was an “association” between the two – not cause and effect.
Eating an ounce of dark chocolate daily has been linked to lower blood pressure in several studies (likely due to healthy chemicals in cacao); a 2011 study suggested dark chocolate could protect the heart; and a 2012 report even proclaimed that frequent chocolate consumption was connected to a lower BMI. We’d all like to believe that! True, this study included nearly 1,000 people, but it used a “food frequency questionnaire” (relying on people to remember how often they ate chocolate) and BMI measurements for a “cross sectional analysis” of those two factors. So all it could show was an association.
Ditto for the 2011 “observational” study on chocolate’s heart-protective properties and “prospective cohort” studies of blueberries and the risk of developing Alzheimer’s over time.
Studies like these may be interesting and even valid, but they have built-in limitations because they were not designed to show direct cause and effect – yet some researchers may draw “conclusions” from a succession of studies that produce similar associations. It’s one reason why studies are so often followed by contradictory research.
In contrast, the just-published study on the Mediterranean diet was a large, five-year clinal trial designed to show whether this diet could prevent heart attacks and strokes. And it did.
So, How Can You Judge Health News?
The fact that medical journals publicize studies to get coverage makes it extra hard to sort the useful from the hype. For a quick-glance evaluation, follow these guidelines.
- Look for key words such as “observational” or “relationship” as you read.
- Check to see how many people were involved. A handful of people does not make a “breakthrough.”
- Did the study just report results in mice? Mice are not little people.
- Whose interests did the study serve? Many chocolate studies are sponsored by cocoa or candy companies.
- Was the study a randomized controlled trial?
Random controlled trials, often used to compare treatments, are considered “the gold standard” of medical research. But they’re costly, and negative findings often don’t make it to the Internet or your daily paper.
What About So-called Patient Anecdotes and “Experts”?
Hyped-up reports frequently feature patient anecdotes, like how someone’s blood pressure “miraculously” went down after eating dark chocolate for just a few weeks. Such anecdotes are not scientific data.
And credentials don’t always mean credibility.
Rx: Healthy Skepticism
If you want to check out health advice, symptoms, or a medical “breakthrough,” head for reliable sources:
- The National Institutes of Health
- The MedlinePlus Medical Encyclopedia
- The Centers for Disease Control and Prevention
- The American Cancer Society and similar organizations offer specialized information vetted by experts.
And then, after you’ve done your research, visit Health News Reviews, a site that regularly critiques over-hyped studies and self-proclaimed experts.
A dose of informed skepticism can’t hurt.