Processed Meat Danger? The Science Behind the Health Debate

Just how unhealthy is processed meat? Well, if you digest the intellectual processed food that is the conventional media headlines, you might confidently conclude that a hot dog really is a metabolic health grenade— in a phallic disguise. Quoting from CNN, "Consumption of even a small amount of processed meat is linked to increased risk of developing type 2 diabetes, ischemic heart disease, and colorectal cancer. Now, here's the thing. Technically, that quote's not wrong. But most articles, including this one, leave out critical nuances, the kind that actually matter to your health decisions every single day. So let's break down and digest the data. Now, this CNN report is based on a new paper about processed meat and health that was published in the journal Nature Medicine. Now, here's a fun exercise if you want. Navigate to the paper and Ctrl+F search the words "weak" and "inconsistent" in the paper. They show up about 18 times in just the main text and the captions. For example, now again quoting from the paper, "These associations each received 2-star ratings reflecting weak relationships or inconsistent input evidence. Or, these associations are rated as relatively weak 2-star relationships, reflecting small effect sizes and/or lack of consistent evidence. We found even weaker 1-star associations between processed meat and ischemic heart disease. Or, simply put, again quoting, the existing evidence is weak. How then do media headlines, internet influencers, and public health authorities come to such confident and non-nuanced conclusions about the negative health impacts, or proposed negative health impacts, of processed meat? Think about that. It is an open question. But now, playing the devil's advocate, yeah, the data are weak, but the pattern is actually consistent, at least across observational studies. And for the big health questions like the relationship to cancer, diabetes, and heart disease, randomized controlled trials— they're impractical, if not impossible, to actually conduct. So what are we left with? We need to rely on these observational data combined with plausible biological mechanisms, however imperfect, these data are. So, admittedly, in general, the data do point in a direction that processed meat is a net negative on health. I'm not here to challenge that narrative per se, or the side to which the preponderance of evidence leans. Based on the lack— I will emphasize the lack— of high-quality data, the precautionary principle can apply. So I would not advocate for processed meat consumption per se. That's not what I'm here to do. However, I'll emphasize it's important to acknowledge the evidence is weak, the current evidence base is riddled with confounders, again quoting from the Nature Medicine paper, "A considerable number of the studies included in this meta-analysis"— it was a meta-analysis— "did not account for dietary confounding factors beyond energy intake." And third, not all processed meat is the same. The rest of this video will focus on this third point because I think it's the most practical for you in your daily decision-making, the most overlooked, and I really don't want you throwing out the biltong with the ballpark hot dog. So, now, to differentiate among processed meats, figure out what is actually bad for your health and what might be taking some unfair blame, we must first ask this question: Why mechanistically are processed meats thought to be unhealthy? In brief, processed meats can contain harmful compounds like polycyclic aromatic hydrocarbons, PAHs, and N-nitroso compounds, NNCS. What I'm going to do here is an abbreviated review, and you can find more information including all the references in the newsletter linked below and also at staycuriousmetabolism.com. But let's get into it. Polycyclic aromatic hydrocarbons, or PAHs. PAHs are formed when organic materials undergo incomplete combustion reactions. This is in car exhaust, cigarette smoke, or yes, smoke burnt and processed meat. And PAH ingestion does carry health risks. Many are known carcinogens that damage DNA, and greater intake is also associated with heart disease and respiratory diseases. But of note, raw meat contains effectively no PAHs. So remember this, it's the burn, not the beef. Now, to help make sense of this from an evolutionary point of view, even if cooking was important to part of our evolution, it's unlikely that we as a developing species ingested high levels of smoke burnt and well-done meat over the course of evolution. And even if early humans did eat lots of smoked or burnt meat, and I'm not saying that's the case, but even if we ate some, evolution doesn't care that much about diseases that strike in our 60s and 70s, well after we've passed on our genes, for the most part. All this is to say, it is legitimate to have concerns about high levels of intake of PAHs, including in processed meat. It doesn't mean a large, well-done ribeye steak is as bad for your health as smoking, but I think it should nudge you to order your next filet medium rare at best. And also as an aside, ordering a good steak well done is probably a bigger crime than PAHs. Okay, now, quick tangent, but an important and quick tip that I think you'll value. When cooking at home, you can actually reduce the PAH formation by using lower temperature cooking, lower duration cooking, and actually using certain marinades, including vinegar and jalapeño pepper marinades, because they contain certain natural antioxidant compounds like capsaicin. They've actually been demonstrated that the ability to reduce PAH formation can be as much as 95%, say with the jalapeño pepper marinade. That's pretty incredible. So these small practical tips can make a meaningful difference in reducing your exposure to these potentially harmful compounds. Also, now as a plug, you should definitely check out this video on AGE, Advanced Glycation End Product Formation, if you want more on the human randomized data on the formation of various harmful compounds in foods and what actually matters to your health. But moving on, I mentioned N-nitroso compounds, NNCS. NNCS are a family of chemicals, some of which are also carcinogens like the PAHs. These form when nitrites or nitrates, often used to preserve processed meats like bacon, deli meats, sausages, and so on, when they react with amino acids or other compounds in food, especially during cooking. But here's the key again, it's the processed meats, specifically those cured with nitrites or nitrates, that are the significant dietary source of NNCs. It's true, also frying or grilling can further increase NNC formation. But, Unprocessed meats, the raw beef, say, typically contain negligible or undetectable levels of NNCs. Are you noticing a pattern yet? Now, you can find processed meats that are labeled with no nitrates added or uncured, and these signal that these options have lower levels of NNCs and are safer for your health. And this is really important in the context of this overall discussion because most studies don't differentiate among processed meats with high versus low levels of NNCs, and this lumping of meats can mean lower NNC meats can take blame for the health risks imposed by their naughty relatives. Now, there are several other classes of compounds that I could discuss that likely also confer health risks associated with processed meats, but the takeaways and practical suggestions actually remained the same. So, to begin with, the takeaways, I have 3 for you. The evidence linking processed meat to poor health outcomes is weak. However, the evidence is also rather consistent, and there is biological plausibility for how specific elements of processing and cooking can create the harm associated with processed meat intake, although not unprocessed meat intake. And third, most of those factors are specific—now I'm just emphasizing—specific to processed meat, and are not intrinsic to the meat itself. Remember that little slogan: "It's the burn, not the beef." Now, for your practical tips, I also have 3. When it comes to animal proteins, eat less processed. Simple enough. 2. When you do process, including cooking your own meat at home, try to avoid prolonged high-temperature cooking like grilling and deep charring. Third, consider marinating your meats, especially in vinegar, acid, or specific spice mixes like jalapeño pepper mix. You can see the newsletter for more details. This reduces generation of these harmful compounds up to 95%. So, the big question: are processed meats a health disaster? No, not always. It depends on what you choose and how you cook it. The headlines, they oversimplify, but the data gives us enough reason to be selective. So you should favor minimally processed options, mind your cooking methods, and in the words of a friend chef, "If you're ordering your wagyu beef well done, well, maybe a greater power is sending you a signal that you shouldn't." Lastly, I just want to reveal— now this is a transparency moment— I was contacted by Fox News to comment on the Nature Medicine paper. This is the blurb I initially sent them. I'm just going to show it to you on screen. I don't know if they'll show the whole thing, it hasn't been released yet. They also shared this CNN article that I featured at the beginning. So what I did is I reached out to the reporter who wrote that CNN article to offer my input and served as a resource. This is the message I sent her. I think it's sad that the nutrition space is so politicized. I can only control so much, but what I can control, or at least offer, is this transparency. If there are updates from Fox or CNN, I will put them in the video notes below. Stay curious, make smart choices, and stay out of echo chambers. Toodles!