A new study, led by Stephan van Vliet of the Duke University Molecular Physiology Institute, has attracted attention owing to its premise: If we dig down, really far down, do plant-based meat alternatives really have the same nutrients as the meat to which they’re the alternative?
Van Vliet’s study compared the nutritional profile of two products: one grass-fed ground beef sample and one sample of an unnamed “popular plant-based meat alternative.” (By reading between the lines, we figured out it was the Impossible burger.) But this study aims to go far beyond the typical nutrition facts label. “We have 13 nutrients appearing on nutrition facts panels,” van Vliet told Modern Farmer in a phone interview. “We have 150 nutritional components that we look at in the USDA database. But foods contain tens of thousands of metabolites.” Those metabolites—bioactive compounds that can play a role in metabolism, ranging from omega-3 fatty acids to vitamins—are far more numerous than simply looking at, say, grams of protein.
The study found significant nutritional differences between the beef and plant-based samples, which makes it a study that will be, and already has been, used as a political and economic talking point for those invested in either the meat industry or the plant-based food industry and the surrounding activist and lobbying groups. But what does this study really say? What can we really take away from it? And, perhaps even more importantly, what does this study not say?
The study used Duke’s metabolomics lab to analyze 190 different metabolites. It found significant differences between the meat and plant-based samples: The plant-based sample contained phenolic compounds, isoflavones and 29 other metabolites that the beef did not, for a total of 31 unique to the plant-based sample. The beef contained 22 metabolites that the plant-based sample did not, including creatine and spermine.
It’s obvious from the beginning that these two samples would contain different nutrients; they are, after all, made of entirely different materials. In the paper, van Vliet writes that creatine, for example, has “potentially important physiological, anti-inflammatory and/or immunomodulatory roles.” Creatine is well known to gym enthusiasts for its muscle-building properties, but it also has some neurocognitive effects; van Vliet referred over the phone to a paper that analyzed cognitive test results in vegetarians and omnivores before and after taking a creatine supplement. He mentioned that the vegetarians had their scores improve after taking a creatine supplement—so wouldn’t it potentially be problematic if those eating plant-based burgers miss out on creatine in beef?
According to that study he referenced, not really, no. In memory tests, for example, van Vliet is right that vegetarians saw their scores rise after taking creatine supplements. But here’s the weird thing: Before taking the creatine, vegetarians and meat-eaters actually had basically the same scores. After taking creatine, vegetarians scored far better on the tests than the meat-eaters, whose scores actually went down. This could be because the body naturally produces creatine on its own; possibly, it’s because a vegetarian body has adjusted to need less creatine; or, possibly, it’s some totally different mechanism that we don’t understand yet.
Creatine is like many thousands of other metabolites, including many that showed up in van Vliet’s study, in that much is unknown about it but that it is, at the moment, not classified as an essential nutrient. “A lot of these nutrients are indeed non-essential or conditionally essential. I would not say they’re not needed; I think that’s too simplistic because it would imply that they’re not important or completely optional,” says van Vliet. Fiber, for example, is not considered essential, although a lack of fiber in a diet would make for an awfully unpleasant existence, gastro-intestinally speaking. An essential nutrient is one that the body needs for survival and which the body cannot produce on its own in sufficient quantities.
Creatine is not that; it’s not worthless, but it’s also important to note that there is not any sort of suggested minimum amount of the stuff that anyone needs to eat. And there’s no evidence that a vegetarian diet creates any sort of creatine deficiency that has an actual physical or cognitive effect on a person—although research on that is still fairly preliminary.
Creatine is just one of the 190 metabolites analyzed in van Vliet’s paper, and it’s one of likely tens of thousands of metabolites in these two foods, so it’s just meant to be an example of how much we don’t know and how it’s very easy to twist research so that it implies a much greater meaning than it should. Van Vliet, to his credit, is absolutely clear on this, and he, in fact, intervened to ensure that even the press release for the study stated definitively that his work does not, nor was it intended to, suggest that meat is healthier or more nutritious than plant-based alternatives or vice versa. But to say that “meat contains creatine, and the meat alternative does not, and creatine is known to have cognitive effects,” well, none of that is technically false. But it’s also pretty misleading.
And that’s what’s happening in parts of the media. “Study: Plant-Based Meat Lacks Nutritional Components of Beef,” reads the headline of one story. “Plant-based meat not nutritionally the same as real meat: study,” reads another.
A common question for vegetarians is how they get protein; this is a ridiculous question. Aside from the fact that there are millions of vegetarians outside the Western world, a review found that vegetarians and vegans in North America and Europe are well within the range of healthy protein intake; it would be more accurate to note that the standard American diet is insanely meat-heavy and that this diet provides a large protein surplus. To van Vliet, though, there’s more to the story than just grams of protein.
It’s absolutely interesting to see what’s going on at a molecular level in these foods, and van Vliet is passionate about how complex nutrition really is. Protein isn’t just protein. “It is important to note that this simplistic view that protein foods are simply interchangeable, that you can eat beef or a bean and get the same nutrients, that’s simply not true,” he says.
That said, van Vliet also said in our conversation that he believes the marketing campaigns around these plant-based alternatives state or imply that they are nutritionally identical to beef. This is not necessarily true. On Impossible Foods’ website, it says: “When it comes to nutrition, we strive to be equivalent to, or better than, the animal-based products we replace.” The site further explains many of the differences between beef and its product: Impossible plant-based meat has, the company says, less fat, less cholesterol and more thiamin, calcium, iron and potassium than beef. This is not saying that its product is nutritionally identical in squalene content or whatever but that it is roughly equivalent.
In a recent ad campaign, Impossible Foods said, “We can replace yesterday’s ridiculous, animal-based technology with a categorically better way of transforming plants into meat. And we can do it with zero compromise on taste, nutrition, convenience or family traditions.” And that phrase, “zero compromise,” when applied to nutrition, is about as close as the company has gotten to saying that its product is a one-to-one equivalent to beef. Even that, I think, does not imply, nor would anyone really think, that a product composed of mostly soy protein would have a chemically identical makeup to beef.
It’s also probably worth noting that van Vliet has received grants and had studies funded by groups such as the North Dakota Beef Commission and the American Egg Board. This particular study had no funding attached, but any association with groups like that can sometimes serve to taint a researcher’s work, at least to the general public. Van Vliet was eager to talk about this and to be transparent about it; he understands why the public might be concerned, given scandals such as the vaping company Juul purchasing an entire issue of a scientific journal for its own purposes.
There is, says van Vliet, simply not enough money lying around in the nonprofit world for scientific research, and sometimes scientists are forced to look to the private sector for cash. “If you want to study red meat, it would make sense to ask for funding from the red meat industry. If I was studying almonds, I would ask the almond board,” he says. But in the studies funded by industry, he says, he had essentially no contact with them after the application process, and he says that neither he nor Duke University (where he works) would accept any sort of pressure to come up with (or bury) any particular findings; he says he has experienced no pressure of this sort. “I think sometimes people have the idea that this is an elaborate scheme, where we’re driving Ferraris because of money from the beef industry that we took,” he says.
Private industry does not fund studies out of scientific curiosity; it funds studies because it thinks it might help the industry. Van Vliet’s past work, and his transparency about his preference for an omnivorous diet, would likely make him an appealing candidate for funding from the meat and egg industry. “If they don’t like my results, and they don’t want to fund me next time, well, fine,” he says. For his part, he seemed to sort of shrug and said that all he can do is make his research as good as he can and put it through the peer review system; the rest of it is out of his control. “All I can say is that, if I was to present my work, I would feel as comfortable presenting in front of a soy board as in front of a beef board,” he says. This particular study is, I think, likely to be used by the meat industry, which can, factually but not entirely truthfully, claim that plant-based alternatives are lacking compared with beef. (Van Vliet agreed that the beef industry would probably like these results.) But that isn’t really the fault of this study.
“For me as a researcher, when I publish these results, of course I’m nervous about the feedback I will get,” van Vliet says. “I figured this would be a touchy topic.”
Van Vliet’s findings are still interesting and still valuable. Our understanding of food is fairly basic; “grams of protein” is not a very precise measurement, compared with all of the compounds that make up food. And it’s possible that, with more information, we will discover that some of these metabolites are important to the well-being of some people. But van Vliet is careful to note, both in his press release and in our conversation, that this is all very complex. Millions of people are perfectly healthy with a vegan or vegetarian diet; millions are perfectly healthy with an omnivorous diet; many are unhealthy with either diet.
Almost as important as what this study found is what it didn’t find, or more specifically, what it wasn’t looking at. This study is one small building block to analyze a healthy diet; it is absolutely not a judgment on omnivorous versus vegetarian diets. Nobody eats only ground beef or only plant-based meat alternatives. Many eat both. “Ultimately, it’s the overall dietary pattern that matters,” says van Vliet. Research is easy to pick and choose to fulfill the aims of industry or philosophy, and it’s easy to cite a study and use it to make an argument you wanted to make already—especially for something as scientifically chaotic and as touchy as nutrition; unfortunately, few will likely take this study for what it really says, despite van Vliet’s efforts to stay neutral.