You might have missed some heartening news that was reported over the holidays.
A newly published review of clinical trials from Purdue University researchers determined that consuming red meat does not affect short-term cardiovascular disease risk factors, such as elevated blood pressure and serum cholesterol.
That statement may come across as obvious, but it isn’t. The volume of clinical research and epidemiologic studies categorizing red meat as the cause of cancer, heart attacks, strokes and a litany of other serious maladies is a wide-open fire hydrant, while the comparable media coverage of red-meat’s-good-for-you stories is that aging faucet over the laundry tub that drips constantly, no matter how hard you twist the handles.
So a study published in the American Journal of Clinical Nutrition that doesn’t demonize the product is good news, right?
Yes and no.
Good in the sense that, if nothing else, it confirms what a majority of Americans intuitively understand: that consuming moderate amounts of meat is a perfectly healthy part of a healthy diet.
And in fact, the lead researcher of the Purdue study tried to put a positive spin on the study’s conclusions.
“During the last 20 years, there have been recommendations to eat less red meat as part of a healthier diet, but our research supports that red meat can be incorporated into a healthier diet,” Wayne Campbell, a professor of nutrition science, said in a statement released by the university.
That’s not exactly a ringing endorsement; more like the kind of bad PR-ese that has the same impact on hearts and minds as the elevator music that plays on hold while you wait for that helpful cable company rep to let you know if you’ll get your service restored sometime that week.
Analyzing the Data
More importantly, it’s important to scrutinize studies that recommend meat with the same vigor that’s applied to those “Eating Meat Causes [fill in the blank]” studies.
First of all, although the press release talks about the team screening “hundreds of research articles,” the study was actually an analysis of only 24 such studies — mainly because such studies are notoriously deficient either in the size of the sample (number of patients) or the methodology used.
Twenty-four studies represents a significant body of data, but it’s not as definitive as a casual reading of the Purdue researchers’ press coverage might suggest.
Second, although the conclusions of the analysis, that consuming more than half a serving a day of red meat (a 3-ounce serving three times a week) did not result in elevated blood pressure and total cholesterol, LDL or triglyceride concentrations, those factors are not necessarily linked directly to the cause-and-effect of heart disease.
Moreover, dietary studies that rely on peoples’ reported consumption patterns over several weeks or months, then link those dietary choices to medical data on cardiovascular incidents, does not make for conclusive recommendations about what’s healthy to eat, and what’s not.
Don’t believe me. Here’s what the authors themselves, as opposed to their press agents, stated about their study:
“Observational associations between red meat intake and cardiovascular disease (CVD) are inconsistent. There are limited comprehensive analyses of randomized controlled trials that investigate the effects of red meat consumption on CVD risk factors.”
In other words, trying to correlate what people say they eat, and the disease conditions we know they develop only suggests — at best — an association between the two sets of data.
Just as the epidemiological studies that finger red meat or processed meats as being linked to higher rates of chronic disease and earlier mortality do not prove causation, so too does this Purdue University study merely suggest that there is but a very weak association between a diet with modest amounts of red meat and “normal” rates of heart disease among that population.
What’s a better indicator of the impact of animal food consumption on a person’s overall health?
How about several hundred thousand years of human history eating meat, however and wherever it could be obtained?
That makes for a pretty significant sample size, I’d say.
The opinions expressed in this commentary are those of Dan Murphy, a veteran journalist and columnist.