As avid followers of health news, you may have noticed that the headlines on certain subjects seem to flip-flop at regular intervals. Nutrition is a notorious area for this: One week, stories are declaring that chocolate and wine will help us evade heart disease. The next, they’re breaking the news that, well, maybe not.
Red meat is one such topic where media messages can feed confusion. There’s a strong body of research linking diets high in unprocessed red meat (beef, pork, lamb) and processed meat (bacon, sausage, deli meats, and the like) to elevated risks of heart disease, some cancers, and other serious health conditions. Accordingly, dietary guidelines from groups like the American Institute for Cancer Research and the American Heart Association recommend limiting those meats in favor of healthier proteins such as fish, beans, nuts, and low-fat dairy foods.
However, there have always been outlier studies, particularly when it comes to the health effects of unprocessed red meat. Some research has suggested that you could eat beef every day and expect no harm to your health, or maybe even benefits. And the media tends to latch onto those types of studies, specifically because they go against the grain. Controversial recommendations issued by a self-appointed “panel” and published in the Annals of Internal Medicine in 2019 garnered numerous headlines when the authors concluded that, given the disagreement among studies, there was “no need to reduce red or processed meat consumption for good health.”
If that makes you want to throw your hands up (or possibly throw some steaks on the grill), there’s a critical point here: Dietary guidelines like the ones I mentioned are based on an ever-evolving totality of evidence. It’s often the case that some individual studies reach conclusions that conflict with the consensus. Sometimes that’s just part of the scientific process (study methods or study populations differ, for example). Sometimes those outlier studies just aren’t well done.
In the case of some studies on red meat, the results may—unfortunately—hinge on who’s funding the work. That’s the conclusion of a new research review, published in the American Journal of Clinical Nutrition in June. It evaluated 44 clinical trials, where participants were randomly assigned to eat either a diet high in unprocessed red meat or some type of comparison diet, for a matter of weeks to months. Each study tested the diets’ short-term effects on cholesterol, triglycerides, blood pressure, or markers of inflammation in the blood vessels.
As it turns out, six of the 44 trials found that eating red meat every day had positive health effects, and all of those studies had ties to the meat industry (they were industry-funded or the study authors had financial links to the industry). In contrast, 11 trials showed detrimental health effects, and none of those studies had ties to the meat industry; instead they were mainly funded by government grants and academic institutions. Of all non-industry trials, about three-quarters found that red meat had negative health effects, while the rest showed no difference versus the comparison diet. The industry trials painted a far different picture: Not one found any negative effects of red meat, and one-fifth pointed to health benefits.
As the review authors point out, we can’t know for sure that industry studies set out to boost red meat’s reputation. But the authors did find a key difference between industry and independent studies: the comparison diets. Industry trials compared red meat against diets high in white meat, or highly refined carbohydrates like white bread and pasta, or even processed meats. That made it likely that red meat would come out looking pretty good, or at least not unhealthy. The independent trials, in contrast, used comparison diets that replaced red meat with high-quality protein sources like fish, tofu, beans, and nuts—in other words, what’s recommended in nutrition guidelines.
I see a couple of main takeaways here. The most straightforward is, keep following the standard guidelines, which put limits on those steaks and beef burgers (and definitely don’t top them with bacon). But there’s also a broader point: Of the 44 trials in this review, two-thirds had industry ties—and that’s an issue in nutrition research in general. Industry funding is common, and there’s accumulating evidence that it does sway the findings. Past reviews have found, for example, that studies funded by the alcohol or soft drink industries find their products to be much more benign than independent research does.
None of this may be shocking information. But at a time when the federal government is slashing funding for all kinds of health research, it’s important information. Nutrition researchers at universities point out that their work has always been underfunded, and they worry that future studies will become even more dependent on industry dollars. Food companies have one basic interest—selling food. Nutrition research aimed at promoting public health requires public funding. Given the role that diet plays in so many chronic health conditions, we need to be investing more, not less.
