Plant-Based Meats (Probably) Won’t Give You Depres

Start wr Plant-based meat alternatives have gotten a lot of attention in recent years, but a recent study found a link between consuming “alternative meat” products and depression. But wait! Don’t throw out those Impossible Burgers and Morningstar Chick’n Nuggets just yet. This study is intriguing, but it deserves a closer look before we draw any big conclusions. This study also had one surprising, important positive health outcome finding that got glossed over in the headlines — and it’s got some glaring weaknesses as well. The source of this study’s data There’s a massive treasure trove of incredible data. It’s called the UK BioBank, and it’s one of the most impressive, most complete health-oriented datasets in the world. It’s a database of health records and genetic data for more than 500,000 residents of the United Kingdom, along with detailed surveys about lifestyle and diet. And it’s incredibly accessible. For basic data access, it’s £3,000, for 3 years. It’s as little as £500 for student researchers. This is amazing for tons of research questions. Researchers can bring their own research questions to this database and search it for correlations, without having to perform their own experiments. It’s an incredible use of democratized data… …but it has also led to a wave of epidemiological papers of, shall we say, dubious quality. All you have to do is plug in a factor or condition (“vegetarians who eat plant-based meat substitutes versus those who don’t”), and see if this happens to correlate with any disease. Ignore the thousands of diseases that don’t correlate well, and write a paper about the couple that do. Which brings us to this study, “Plant-Based Meat Alternatives Intake and Its Association With Health Status Among Vegetarians of the UK Biobank Volunteer Population.” The researchers looked at a dietary questionnaire that was given to all the UKB members. If you marked down that you ate any plant-based meat alternative (PBMA) within the last 48 hours, you were in the experimental group. If you marked down that you were vegetarian but didn’t eat any plant-based meat alternative, you were in the control group. Next, they looked at about diseases in UK BioBank to see if any correlated with this split; did the experimental group show a significantly higher or lower likelihood of developing a disease? What the study found Of the 45 diseases, 3 showed a correlation that was significant: PBMA eaters were more likely to have depression (42% higher incidence rate). PBMA eaters were less likely to have irritable bowel syndrome (IBS) (40% lower incidence rate). PBMA eaters were far more likely to develop bronchiectasis, a long-term lung disease where permanent widening leads to mucus buildup and frequent infections (228% higher incidence rate!). Hold on a minute. That last disease seems out of place. No one was putting fake meat products directly into their lungs. This raises one of the red flags with these sorts of association studies: sometimes, things that seem like a pattern still turn out to be a quirk of random chance. And it’s a bit odd that the other two conditions have opposite incidence rates. Why would eating PBMAs, a food that’s grouped as ultra-processed (contains preservatives, sweeteners, emulsifiers, artificial colors and flavors, generally considered as unhealthy) reduce the chances of getting irritable bowel syndrome? Additionally, IBS is strongly correlated with an increased chance of depression. Why are these PBMA eaters more depressed, with less bowel disease? There’s also a correlation (just under the cutoff for significance) to constipation, with PBMA consumers showing a ~32% reduced incidence of clinical constipation. All of this points to big limitations with using this sort of data to draw any kind of meaningful conclusion. Don’t judge someone based on one day’s diet Remember, the researchers classified UKB participants as either PBMA consumers or non-consumers based on a survey. Essentially, participants were asked “write down everything you ate in the last 24 hours.” The participants took this survey anywhere from 1 to 5 times, usually 3 months apart. But those little slices of someone’s diet are probably not enough to say for certain whether they regularly consume PBMAs. Most of us do not eat the same foods every day, or always buy the same meals at the supermarket. And if someone tried PBMAs a single time, if they noted it on their survey, they were immediately sorted as a “alternative meat consumer,” even if they never bought it again. Even the authors conclude, in their abstract: no clear health risks or benefits were associated with PBMA consumption in vegetarians[.] Additionally, correlations tell us nothing about causation or directionality. What if the directionality goes the other way? Perhaps depressed individuals are more likely to buy ultra-processed meat substitutes, like faux-chicken nuggets or burgers, than less depressed people. Depression can make it harder to muster the energy to cook a meal from scratch, which could make premade foods more appealing. Overall, this study is probably either making much ado over nothing (a “ghost” trend that isn’t actually real), or it’s providing an interesting starting point for further research. It could turn out that certain components in plant-based meat alternatives might provide some level of protective effect against irritable bowel syndrome. If so, that might be an amazing breakthrough! But for now, it’s just not enough evidence for me to draw solid conclusions. I am not fully vegetarian, but I strive to eat less meat in my overall diet (for both health reasons, and because it’s better for the environment). I’ve tried PBMAs, and they range from “ugh” to “that’s pretty darn good.” I’m not eating PBMAs every day, but I’m also not planning to change my consumption habits from this study. Depression is complex, but it’s likely not stemming solely from whether my occasional chicken nuggets contain actual fowl.iting...