Your Dog is a Biohack! Here's the Science

If there are two things I love in this world, it's health sciences and dogs. They are obsessions. And as much as they might seem like separate topics, they're not. From improving heart health to reducing anxiety to protecting against allergies and even death to detecting cancer and pandemic-causing viral infections, dogs aren't just our best friends. Dogs are medicine. And I'm going to prove it to you in this video. Let's start with a shocking statistic. In an analysis, a meta-analysis of roughly 4 million people, dog ownership was associated with a 24% reduced risk of death. That's not a verbal slip. Not 2%, not 4%, a 24% reduced risk of death. And the effect was largely driven by a 31% reduced risk of death from cardiovascular disease and remarkable substantial—65% reduced risk of death in people with prior cardiac events. Now, I will caveat these findings. It's true these are observational studies, they're not randomized controlled trials, although we will touch on those momentarily. However, even assuming there are some confounders, the relationship is large and consistent. For example, in all 5 studies with follow-up periods greater than 10 years, dog ownership was associated with a reduced risk death. And in all the studies examining death from cardiovascular disease, dog ownership was again every time associated with the reduced risk of death. So we've established the association between dog ownership and positive health outcomes, particularly mortality—death—and cardiovascular disease. It's large and consistent. But the astute viewer will now want to know how. Because if there is a cause-effect relationship between canines and our health, we want to know the mechanism. So in the rest of this video, we are going to review 5 ways your dogs help out your heart and overall health. And you're really going to want to stick around until the end with this one, because these furry facts, they just get better and better. So with that, let's begin. 1. Reduced blood pressure. In a randomized controlled trial, 48 men and women with stage 2 hypertension, so basically very high blood pressure, they were all put on medications for their blood pressure, and additionally they were randomized to either receive a pet, a dog or a cat, or to a control group with no pets. And they were then subjected to mental stressors. In this case, it was a mental math and/or speech test, which, believe it or not, in a lab setting reliably promote a cardiovascular stress response, a boost in blood pressure and heart rate. Impressively, after 6 months of pet ownership, the increase in blood pressure caused by these mental stressors was substantially reduced by pet ownership by as much as half. So you can see that here in this graph, the gray bars represent the pet group, those who own dogs and cats, and the black bars represent the control group, no pets. What you can see is blood pressure increased in response to the stressors, the math and the speech tests, but far, far less in participants who were randomized to receive dogs or cats. And as a really cool added benefit, the pet owners ended up performing way better on the cognitive tasks. At the beginning of the study, all the participants in both groups had roughly a 75% correct performance rate. But by the end of the study, the control group still exhibited the same C-level 75% correct performance rate, whereas the pet owners, those who got randomized to own dogs and cats, they demonstrated a 92% correct performance rate. So in effect, the pets reduced the stress response, reduced blood pressure, and as an added bonus, made the participants smarter. Now, as a quick nuance note, sadly, in this randomized control trial, there was no subgroup analysis to compare the effects of dogs versus cats. But I will tease, we do get to that later in the video. And spoiler alert, dog owners kind of have the edge. So dogs, they can lower your blood pressure, but it turns out they've also mastered the chemistry of connection, which brings us to part 2, puppy eyes and the chemistry of connection. Maybe you've heard of the hormone oxytocin. Oxytocin has earned its reputation as the love hormone or the love chemical due to its critical role in facilitating social bonding between mothers and infants. But over the course of dog domestication and their co-evolution with humans, dogs have cleverly co-opted this hormonal system to their advantage. So pause, it makes perfect sense, doesn't it? The canine lineage has long benefited from forming close relationships, partnerships with human beings. They can get food from us. To truly tap into our social networks and secure their place by our side, they needed an entry point. And what better gateway than the very hormonal system we evolved to bond mother to infant and infant to mother? Now, one of the most fundamental manifestations of this social attachment is called mutual gaze. The prolonged eye contact that fosters emotional connection between mother and child. You likely recognize this instinctively. It's that "aww, so cute" reaction you experience when looking at an adorable baby or an adorable puppy. And this isn't merely physiologic speculation. In a landmark study published in the prestigious journal Science, researchers observed dogs gazing at their owners and measured oxytocin levels in their owner's urine. And remarkably, prolonged gazes from dogs to their owners significantly boosted oxytocin levels in their human companions, indicated by the black circles in this graph. And interestingly, the effect was absent during just brief gazes, the white circles, and when gazing by hand-raised wolves as a control group. This underscores the phenomenon is unique to domesticated dogs, which co-evolved with us. And equally as intriguing, when the researchers administered exogenous oxytocin to female dogs, when they gave the dogs oxytocin, the duration of the dog's gaze towards their owners increased, reinforcing a positive feedback loop. So the researchers of this paper, they concluded that mutual gaze between domesticated dogs and humans It's effectively hijacked the very same neurochemical pathway we established to bond mother and infants, creating an oxytocin-driven positive feedback loop that cements the human-dog relationship. I know, you're never going to look at puppy dog eyes the same. In this co-evolution with dogs, it's not just for social bonding. It may offer direct neuropsychological benefits for humans. Because oxytocin doesn't just foster social connection, it also acts as a natural anxiety reducer, or anxiolytic if you want the medical jargon. In fact, genetic differences in oxytocin receptors have been linked to higher rates of anxiety, and researchers are actually exploring intranasal oxytocin—oxytocin up the nose—as a potential treatment for anxiety and other mental health conditions. Now admittedly, we're still a long way away from doctors handing out oxytocin nasal sprays for anxiety. This is in part because the neuropharmacology is really complex, and it's really difficult or impossible with current technologies to target the specific brain regions where oxytocin is most effective, at least with a nasal spray. But the really good news? You don't need a prescription to snuggle a puppy. Although, wouldn't it be lovely if your insurance company covered puppies? I wish it did. Anyway, the takeaway: our bond with dogs, it's not just emotional, it's neurobiological. By activating the oxytocin system, our four-legged friends, our companions, not only deepen social bonds, they might also help ease anxiety and support better mental health. Isn't that cool? But now I want you to buckle up because This next study completely floored me. It's about food allergies, a 90% reduction in food allergies. In a randomized controlled trial involving 1,303 3-month-old infants, dog ownership was associated with, yes, a 90% reduced risk of developing a food allergy. Let me say that for a third time, a 90% reduction in food allergies. There is no medication on the planet that has an effect that large and positive. It almost sounds unbelievable, but when you stop to think about it, it makes perfect sense. Dogs not exactly being the most sterile members of the household, they expose newborns' immune systems to foreign compounds called antigens, which can help train and prime the immune system during a critical early period of development. So while you're busy teaching Fido to sit and stay, he's busy teaching your baby's immune system the difference between friend and foe. And I'm gonna get some hate for this one. I hate to disappoint cat people, but while your feline overlord might control your schedule and sleeping position, they don't seem to boost your immune system quite like dogs. In this study, they also looked at cat ownership, and though there was a trend towards reduced food allergies in households with cats, it did not reach statistical significance, nor did it approach the immune-boosting benefits seen with dog ownership. So yeah, that's +10 points for dog people. Sorry, cat people. Don't hate me. And just to hammer home how impressive these immunomodulatory benefits are, consider this: in this same study, there was no significant relationship between antibiotic use or mode of delivery—mode of birth, be it vaginal versus C-section. These are generally thought to be pretty important factors in determining immune development, but dogs dominated over these factors when it comes to the development of food allergies. So, like a corgi, in short, when it comes to preventing food allergies, dogs might just be nature's sneaky little pediatricians. Moving on, our penultimate, number 4: increased physical activity. Before we get into our grand finale, the most mind-blowing benefit, Let's stretch our legs a little bit with one that's less surprising, but also packs a real health punch. Because let's be honest, staying consistent with movement and exercise over the day isn't always easy, especially in Boston winters. But when you got a furry little friend staring at you with its puppy dog eyes, which are causing oxytocin release, and a leash in its mouth pleading, "Take me outside." Hey, do you wanna outside, Grammy? Suddenly, skipping movement isn't really an option. And the science backs this up. Multiple studies show that dog owners engage in significantly more physical activity than non-dog owners. And yes, the effect sizes vary study to study, but the effect is reliable. And frankly, it just makes intuitive sense, doesn't it? It may not feel like much at the time, hopefully because you're distracted and having fun, but those regular low-intensity activity breakups, like walking your dog or just playing around on the floor with your dog, They improve circulation, they provide bursts of visual and tactile stimulation, and increase non-exercise activity thermogenesis , which is a major source of calorie burning. And all these effects, these small steady deposits into your health piggy bank, over time, they compound into real health benefits. Alright, now we've covered blood pressure, brain chemistry and co-evolution, food allergies, and movement. But dogs, they have another superpower that sounds almost too good to be true, until you see the shocking science. So this brings us to our final chapter. 5. Canines for cancer and C-virus detection. As sniffer dogs are routinely used to locate drugs, explosives, toxic wastes, and more, it's logical to think we might use them to detect diseases. So from cancer to viral infections that cause global pandemics, different diseases, they give off different volatile organic compounds that dogs can detect with their amazing sense of smell. A dog's ability for odor detection, it's about 100,000 times better than that of your average human. And dogs, they can detect these volatile organic compounds coming off different disease states at concentrations as small as 1 part per trillion. That is one part per trillion with a T. But you don't just want speculation, you want dog data. So here it is. Dogs have been successfully used to identify various cancers including skin cancers, melanoma, prostate cancer, lung cancers, ovarian cancer. For example, in one double-blinded study, 3 beagles, they pinpointed non-small cell lung cancer with a sensitivity and specificity of, get this, 97%, and they did it in under 10 seconds. And similar findings have been reported for other cancers using blood, breath, and urine samples from patients. That's remarkable. And given these outcomes, I'm inclined to agree with the authors who wrote this paper. They write, "Scent detection dogs deserve a larger role in public health protection." I agree. Do you? Now, If raising the issues of dogs versus cats weren't provocative enough, let's talk about the C-virus, which I'm not naming because YouTube dings that. In another study, dogs were conditioned to detect this C-virus infection with remarkable precision. Even in live detection tests where the dog's attention was challenged by environmental distractions, the canines achieved 95% agreement with gold standard PCR testing for identifying both infected and non-infected individuals. And again, it took the dogs less than 10 seconds to sniff out the virus. That is compared to more than a day for PCR test results. So all this raises an obvious question: if dogs can sniff out explosives at airports and cancer and viruses in seconds, why aren't we using them more in public health? Their noses might just be one of the most underutilized diagnostic or screening tools that we have. So to recap, dogs, they lower your blood pressure, reduce stress, boost brain chemistry and oxytocin, babysit your baby's immune system, guilt-trip you into exercising, and they can sniff out cancer and viral infections faster than lab tests. Honestly, at this point I'm starting to wonder why dogs aren't running the healthcare system. Because look, they work for treats, they never cancel appointments, their bedside manner is impeccable— unless you're a mailman, of course. "Aah! Aah! Aah!" So, moral of the story: you thought you were rescuing them. Turns out, they've been rescuing you all along. Now, if you liked this video, tell me what your favorite fact was below, or teach me something I don't know, or just brag about your dog. Tell me about them. And if you want to learn more about dogs and health, what I'm going to do is I'm going to comb through the comments here and on the associated newsletter. And then I'm going to add to the newsletter. You can find it at staycuriousmetabolism.com or at the link below. Let's pool our dog knowledge and show our furry friends how much we love them. Stay curious. I hope you like this one.