It looks like we soon may be able to chalk up another win for the power of the canine nose.
In a recent UK National Health Service (NHS) preliminary study, trained dogs were able to sniff out prostate cancer 9 out of 10 times, making them a more accurate predictor than the standard (but controversial) Prostate-Specific Antigen (PSA) screening test, which has a high "false positive" rate.
For men of a certain age, the prostate goes from a background to a foreground worry. The walnut-sized gland circles the neck of the male bladder, and when it starts causing problems, there can be a number of reasons. The most serious is cancer. To arrive at a definitive diagnosis requires a biopsy, which--like any surgery--comes with its own risks. And this is why the "false positive" rate matters: in order to make a decision to go ahead with a biopsy, a man needs to have a pretty good idea that it's needed. The more accurate the screening, the fewer unnecessary biopsies.
Based on the success of the preliminary study, the NHS has recently authorized clinical trials to more definitively test the canine ability to identify prostate cancer. Dogs trained by the group Medical Detection Dogs will be taking part in the upcoming trials. This group, co-founded by by Dr. Claire Guest, was among those profiled in Barbara Robertson's Wonder Dogs article; click on over to read more about it.
Wellness: Healthy Living
Investigating the microscopic worlds in our dogs may reveal pathways to better health.
The microbiome is the invisible world of the hundred trillion bacterial, viral and fungal microbes that live on us and in us—on our hair and skin, behind our ears and inside our eyelids. The bulk of these miniscule microbes are good guys, gut microbiota that congregate in the digestive tract, where they bolster the immune system, manufacture vitamins and digest food to generate nutrients and energy.
Microbial equilibrium is a delicate balancing act, and a broad spectrum of inflammatory and autoimmune diseases is linked to having too many microbes—or too few. For example, researchers know that significantly lower bacterial diversity is found in both people and dogs with chronic inflammatory bowel diseases.
Teasing out the biological interaction of trillions of miniscule microorganisms that colonize the body, and the role they play in well being, is a new frontier. Will it be a watershed moment in veterinary medicine? Scientists are hopeful. The human microbiome has become a hot topic in biologic investigations, and canine research is fast catching up, much of it inspired by the success of the Human Microbiome Project, launched in 2007 by the National Institutes of Health (NIH). Using stool and tissue samples to isolate microorganisms, researchers are mapping the diversity and normal profile of the human microbial community.
Another undertaking, the Human Food Project, invites the public to submit personal and family microbial samples along with samples from family dogs to better understand how a person’s microbiome compares to that of animals living in the same environment. (The project’s dog segment has been discontinued.) The analysis centers on the anthropological co-evolution of humans, animal and plant microbes to understand modern disease against the backdrop of our ancestral/microbial past.
It’s all about dogs at Companion PBx, a new startup that primarily targets the canine digestive tract. Its goal is to build a cumulative gut flora database and develop dietary products customized for dogs’ digestive health. In January 2015, the company launched a Kickstarter campaign to raise money for construction of the database.
According to Companion PBx Chief Science Officer Kelly Scott Swanson, PhD, who’s on the faculty at University of Illinois, Urbana-Champaign’s Department of Animal Sciences, “By sequencing the microbes in your pet’s sample, we obtain a fingerprint of the microbial community in your pet’s GI tract.”
Microbes in Common
Affected by age, environment, ancestry, evolution, genetics and diet, microbial communities vary widely between species and across individuals within a species. A recent study suggests that our housemates—including the family dog—may also affect the composition of our personal microbial signature.
If you and your significant other kiss, hug and/or share a bed with your dog, the three of you have more in common than you think. A study conducted by researchers at the University of Colorado, Boulder, revealed several similarities: Adults who share a dog have more similar mouth microbes than those who don’t. Dog-owning families have more diverse and different microbial colonies than dogless households. Parents tend to share more kinds of mouth bacteria with their dog than they do their children. And children raised with dogs have a wider variety of microbes than dogless kids (Song et al. 2013).
Whether these spit-swapped microbes serve a purpose or are just passing through is not clear. But research shows that children raised with dogs are less likely to be afflicted by eczema (Epstein et al. 2010) and asthma (American Society for Microbiology 2012).
The notion that microorganisms in the canine gastrointestinal tract might have unique properties is not new. Early Romans understood the medical value of a well-run therapy dog program. Health temples, the ancient equivalent of modern-day outpatient clinics, were staffed with live-in cynotherapists, gentle dogs who wandered about the grounds greeting patients and licking wounds. Were the dogs healing only psychosomatic injuries? Time and additional research funding will tell.
The idea that our microorganisms may to some extent be collectively beneficial is intriguing. People and dogs have been exchanging microbes for at least 30,000 years, since the first little cave girl kissed the first proto-dog puppy smack on the muzzle. That’s a long history of sharing. It’s possible that our microorganisms are at least symbiotic, and perhaps even played a role in the dramatic domestication of the dog.
Theoretically, many thousands of years ago, a population of carnivorous wolves or ancient proto-dogs (depending on where you stand in the dog-domestication debate) transitioned from a meat-heavy diet to one laden with grain, a consequence of the agrarian revolution.
Scientists know that the acquisition of a new diet is a fundamental driver for the evolution of a new species (Dale, Moran 2006). When species transition from carnivorous to omnivorous diets, the gut microbial community co-diversifies with the host and drives further evolution (Ley et al. 2008). As human diets changed, so too did those of Canis familiaris. Over time, as we incorporated these unique animals into our daily lives, we continued to reshape them.
In humans, autoimmune and inflammatory diseases are on the increase. Scientists can’t verify a similar pattern in dogs because epidemiological studies are rarely conducted in veterinary medicine. Additionally, many autoimmune conditions are diagnosed based on the patient’s subjective description of symptoms.
But this is not the case with itchy skin. Dogs who scratch themselves incessantly are highly likely to have allergies. When researchers compared microbial colonies on the skin of healthy dogs to those of dogs with allergies, they found that non-allergic dogs have much richer and diverse skin microbial communities (Hoffmann et al. 2014).
But when it comes to proving causality, scientists wisely err on the side of caution. It’s not understood if a change in the microbiome causes certain conditions, or if it occurs as a consequence of the conditions. Nor is it absolutely clear that more diversity is better than less. At this point, scientists cannot say with confidence exactly what a healthy microbiome should look like in the dog.
Moreover, what seems logical may not be so. For instance, anyone who has lived with a poop-eating pooch has wondered why some dogs do and other don’t. Are coprophagic dogs seeking microbes lacking in their gut? Surprisingly, research involving mice suggests that this might not be the case; coprophagia in germfree mice is the same as in conventional lab mice (Ebino et al. 1987).
Other questions arise: Are the microbiomes of individual dog breeds more similar to each other than they are to those of other breeds? And could these isolated microbial communities drive breed-specific ailments?
Jan Suchodolski, DVM, a Texas A&M veterinary medical and biomedical sciences researcher who studies dog and cat gastrointestinal diseases, says that this doesn’t seem to be the case. As he noted, “So far, we do not have any clear evidence that gut microbiomes are more similar within breeds. Environmental influences such as age, diets and antibiotics, and especially the effects of GI disease, are larger than any breed effect.
“It may be possible that we missed an effect, as we have not evaluated thousands of animals. But if there were a breed effect, it would probably be very minor. Even within puppies of the same litter, the microbiome shows huge inter-animal variation, so the animal effect is much stronger than any other effect.”
Idiopathic canine inflammatory bowel disease (IBD) is a gastrointestinal condition in which the digestive tract is chronically inflamed. Symptoms include vomiting, diarrhea and weight loss. Dogs with IBD have significantly lower bacterial diversity as well as microbial communities that are distinct from those of healthy dogs. In 2014, Dr. Suchodolski and his colleagues conducted a study of 22 companion dogs, half of whom suffered from idiopathic IBD (Minamoto et al. 2015). They wanted to know if traditional treatments—steroids and special diets—directly or indirectly created a more robust microbial community.
After treatment, the sick dogs felt a lot better. However, there was no change in their gut microbiota. The researchers concluded, “This study demonstrates intestinal dysbiosis [microbial imbalance] and altered serum metabolite profiles in dogs with IBD. But medical therapy doesn't seem to affect the intestinal dysbiosis.”
It could be that, rather than triggering the condition, microorganisms are compromised by it. Researchers also suspect that biological environmental stresses are involved in ways not yet understood. Dr. Suchodolski added, “It may be that we need longer follow-up periods of treatments to see potential improvements. Another reasonable theory is that with the current standard therapies—for instance, immunosuppression—we just control clinical signs, but the underlying etiology of the disease is ongoing.”
When it comes to treating dogs for myriad problems, vets often prescribe antibiotics, and for good reason: antibiotics save lives. But the war on infection sometimes puts good bacteria in the line of fire, too. When assaulted by repeated antibiotic use, some classes of gut bacteria struggle to recover. If the affected bacteria play a pivotal role in autoimmune health, overuse of antibiotics may coincide with a decrease in healthy autoimmune responses.
Antibiotics are not the only culprits. Scientists suspect that in human births, Cesarean deliveries may contribute to an increase in autoimmune weaknesses as well. In a vaginal birth, the fetus departs the womb without a single microbe but acquires them by passing through the mother’s birth canal. By the time the newborn takes his first breath, he is covered with colonies of bacteria that kick-start his immune system, establish a healthy digestive tract, help shape his growing brain and even protect him from psychiatric disorders. C-section babies start life without the microbes they would have picked up from vaginal delivery, suggesting that the colonization of the newborn might be delayed (Jakobsson et al. 2014).
Medical disorders connected to non-vaginal delivery and the slow introduction of protective bacteria have not been studied in the dog. Considering that a number of breeds with exceptionally flat, wide skulls—such as the Boston Terrier, French Bulldog and Bulldog—must have their pups delivered via C-section, it’s an area that deserves further study.
Or is diet the problem? Commercially manufactured dog chow was introduced in the U.S. in the mid-1920s. By the 1950s, processed dog food like Friskies, Sergeant’s and Purina were widely available through local grocery stores. Today in the U.S., we spend more than $10 billion a year on commercial pet food. The question arises: has the increase in autoimmune diseases paralleled the rise in popularity of processed dog food?
Because veterinary practices typically don’t collect this type of empirical data, the answer is, at best, a guess. But many dog owners think so, and have eliminated or cut back on processed foods in favor of raw meat and vegetables. However, as of now, there is no definitive evidence to show that fresh foods modulate the gut microbiota.
Sophisticated DNA sequencing technology has opened up the invisible world to scientific scrutiny. But determining its impact on the host species is difficult and time-consuming. Researchers need to locate and identify a microbe’s fingerprint, then remove a sample and grow it in a culture, a process especially difficult with shyer microbes that are destroyed by oxygen or stomach acid.
To figure out why we get sick and the role microbes play in illness, researchers must first determine how these trillions of organisms interact with each other. And the fact that scientists can prove a problem exists doesn’t mean they know how to fix it.
Developing therapeutic dog foods that target specific vulnerabilities may help, but will take time to develop. Although the probiotic movement may oversell their benefits, probiotics (friendly bacteria like those that live in the gut) are effective in some cases. And prebiotics, foods that encourage growth of good bacteria already present, may help as well.
The University of Pennsylvania School of Veterinary Medicine (Penn Vet) is recruiting dogs with acute symptoms of diarrhea and/or vomiting for a new clinical trail that will evaluate the role of the intestinal microbiome—the community of “good” bacteria that live in the gut—on chronic gastrointestinal diseases. Therapy will include simple diet change, treatment with antibiotics or combination therapy with steroids for more complicated cases.
Penn Vet researchers anticipate that their study may reveal how gut microbiota influence and respond to treatment, which in turn could lay the groundwork for future projects using treatments such as prebiotics, probiotics or fecal transplants (transferring “good” microorganisms from a donor’s healthy stool to the patient’s gastrointestinal tract). According to Research Assistant Professor Dr. Daniel Beiting, “Whereas past studies have used a single method to sequence bacterial DNA, the Penn Vet study will use a more sophisticated approach called metagenomics, generating a much more comprehensive catalog of bacteria in the stool and providing insight into what they might be doing.”
Penn Vet is currently looking for dogs with chronic gastrointestinal problems. People interested in enrolling their dog in the study—Evaluating the Role of the Microbiome in the Resolution of Canine Chronic Enteropathy—should email Penn Vet’s Veterinary Clinical Investigations Center at email@example.com, or call (215) 573-0302.
Future possibilities are exciting. In the meantime, kiss your dog. It’s good for you in more ways than one.
Good Dog: Studies & Research
Dogs’ remarkable ability to sniff out disease is opening doors to earlier cancer detection.
Cancer. The very word strikes fear in us. A voraciously living thing, cancer is an uncontrolled division of abnormal cells that destroy nearby healthy tissue. Because the natural, life-building process of cell division isn’t perfect, cancer has always been part of the human experience, one that eventually has an impact on everyone—if not directly, then when a relative, friend or companion animal is diagnosed with it.
The fact that human illness often comes with a signature odor is also old news. Infectious diseases such as cholera, diphtheria, smallpox, pneumonia, tuberculosis, typhoid fever and yellow fever have long been known to produce signature odors. Parents and doctors have used their noses to detect things like strep throat (metallic-smelling breath), phenylketonuria or PKU (in which the baby’s sweat smells like locker-room towels), even schizophrenia (a musty smell).
Mammals evolved using odors to find food, avoid illness-inducing spoiled or poisonous food, detect toxins in the environment, distinguish friend from predator, and assess well being. Following our noses is likely one of the key reasons humans, canines and other mammals developed large brains: to process all those smells.
Dogs are quite up front about this smelling stuff, greeting each other with a thorough sniff from tip to tail (or vice versa), quickly gathering a wealth of information through their noses. Humans do the same thing, just not quite so boldly. Historically, we’ve taken advantage of dogs’ superior sense of smell to track people and animals and to detect drugs, bombs and chemicals.
What is new is the increasing role dogs are playing in helping us detect minute, microscopic things we can’t see and certainly can’t smell, like cancer in its earliest stages, when it’s most treatable.
What exactly are dogs picking up with their remarkable olfactory sense? Turns out, it’s volatile organic compounds, or VOCs. Simply put, VOCs are chemicals coming from a living or once-living organism that can pass into the surrounding air (“volatile” in this case means easily evaporated at normal temperatures). VOCs, which can be natural or human-made, are both numerous and ubiquitous. Our bodies constantly emit an incredible array of VOCs, some of which are odorous and some of which are not.
VOCs are first secreted at the cell level, finding their way into our blood, breath, skin, sweat, urine and feces and from there into the air, rather like the dead skin cells (dander) we slough off on a daily basis. VOCs vary depending the individual’s age, gender, diet and health, and possibly even genetic background. Just as our fingerprints and irises are uniquely individual, so is our fragrance.
Illness resulting from infectious diseases and metabolic disorders, including cancer, influence and change our VOCs—our odor profile. While we may or may not smell the change, dogs certainly can. The average dog has a sense of smell that is between 10,000 to 100,000 times keener than the average human’s, and the part of the dog’s brain that analyzes smell is proportionally 40 times greater than ours. This allows them to detect specific odors, including specific VOCs, in parts per trillion. One scientist described this as being able to detect one rotten apple in a barrel of two million.
Dogs often display intense interest in a new cut on their person’s leg or arm, putting their nose close to the wound and sniffing with purpose several times. When they do this, they’re inhaling the VOCs put out by the body’s blood and changing skin cells as they waft into the air. It’s not a stretch to understand how, using dogs’ built-in and potentially life-saving ability, individual dogs can be trained to detect and alert to specific VOCs associated with a wide variety of conditions in a more general way.
Cancer has been the most recent focus of this sort of research. The earlier cancer is detected, the better the patient’s chances are for survival. Dogs can detect certain cancers with high levels of accuracy long before some of the more traditional diagnostic methods. The trick is identifying the signature VOC that relates to a specific type of cancer so that the dog can be trained to alert to it.
Researchers are making great progress. Dogs have been trained to detect ovarian cancer in blood samples, distinguishing it from other gynecological cancers and healthy control samples. They have also been trained to detect melanoma, bladder, colorectal and lung cancer in patients’ urine, tumor or breath samples. Because this research is in its early stages, it’s not yet clear whether the dogs are detecting VOCs from the cancer cells or from other metabolic processes often seen in patients with cancer.
Italian researchers were able to train two German Shepherds, Liu and Zoey, to sniff out VOCs associated with prostate cancer in urine samples with 98 percent accuracy. The study’s remarkable results—far better than those achieved with standard PSA tests—were based on samples from 362 men with prostate cancer and 540 men with either non-neoplastic prostate disease or non-prostatic tumors. Liu and Zoey could tell the difference.*
Using chemical-analysis techniques such as gas chromatography and mass spectrometry, researchers are regularly adding VOCs to the list of components known to be associated with specific cancers, infectious diseases and metabolic disorders. This work is opening doors not just to improvements in the art of diagnosis but also, to the understanding of disease processes, which leads to better treatment, novel therapies or perhaps prevention.
Scientists are also reverse-engineering the dog nose to come up with electronic or artificial sniffers to detect those same VOCs, enhancing doctors’ ability to quickly and definitively diagnose various diseases and conditions in a simple, non-invasive way without using a dog. In 2013, over a thousand journal articles discussed the electronic nose in some way.
Before long, physicians may be waving an electronic nose over our bodies to diagnose illness, as Dr. McCoy did with Captain Kirk and Spock on Star Trek. If so, we’ll have our dogs’ wet, cold and very keen noses to thank.
*Lead researcher Gianluigi Taverna, MD, chief of the prostatic disease unit at Humanitas Research Hospital in Milan, presented these results in May 2014 at the annual scientific meeting of the American Urological Association, and referred to the highly trained dogs as “Ferraris.”
Learning a dog's heritage has its benefits
When we adopted our dog Charlie from the Sacramento Independent Rescuers, his foster mom, Shana Laursen, who specializes in Greyhound rescue with Greyhound Friends for Life, told us that he probably had some Whippet in him, thinking that not only his brindle coloring but the “set” of his back legs indicated that he might have a sprinter in him. She also added that was one of the reasons she picked him to foster. Lucky for us she did because by the time we saw his posting on Petfinder I had been getting discouraged after scouring for weeks online pet adoption services nationwide and local shelters to find a scruffy male terrier to be the “bro” to our three female dogs.
At that time we didn’t really know what breeds contributed to making Charlie the perfect match that he turned out to be. Some type of terrier definitely in the ascendency, his very first night in his new home found him scooting under the covers to sleep at my side, a position he has proudly claimed since. As for the Whippet? Sometimes he manages to keep up with our speedy Pointer, Lola, so perhaps Shana might be right. It was time to figure that out, so we decided to “test” Charles’ DNA using the really easy-to-use, Mars Wisdom Panel DNA test.
Unlike other genetic tests that rely on blood samples, for this one you only need to collect saliva samples from inside your dog’s mouth, using the two swabs that come with the kit. Next you dry the swabs out for a few minutes placing them in a convenient “holder” that comes with the kit. Next you register the sample online, filling out a few basic profile questions about the sex/age/weight of the dog. Plus they pose some really interesting optional questions like the reasons why you are doing the test—perhaps you want to understand your dog’s behavior better, or confirm the breed make up of a prospective adoptee, predict the adult size of a pup, or testing for health reasons? Many breeds are prone to a variety of genetic diseases, so it is beneficial to know what breeds your mixed breed dog might be, for possible preventive or diagnostic reasons. Importantly, this newest version of the Wisdom Panel 3.0 also includes a screening for the genetic mutation for MDR1 or Multi-Drug Resistance 1 that can be a really important consideration, and which can affect many herding breeds. As it is explained on their website:
“The MDR1 gene is responsible for production of a protein called P-glycoprotein. The P-glycoprotein molecule is a drug transport pump that plays an important role in limiting drug absorption and distribution (particularly to the brain) and enhancing the excretion/elimination of many drugs used in dogs. Dogs with the MDR1 mutation may have severe adverse reactions to some common drugs. Although the mutation is most closely associated with some purebreds, it can also be found in mixed-breed dogs. Therefore it is important for owners of mix-breeds to test their dogs and to share the results with their veterinarian in order to provide their pet with the best possible care. The discovery of the MDR1 mutation in dogs was made by Washington State University.”
While it is unlikely that terrier-mix Charlie has any herding breeds in him, he might have a Whippet ancestor—the long-haired variety having a 65% frequency of this mutation—so it is good for us to find this out now.
Browsing around their interesting site I also found this very informative video that explains the genetics behind a dog’s physical characteristics. I actually learned a lot from watching it, including the reason that many dogs have white markings on the their feet and paws—or on areas farther away from the dog’s back (where the dominate color starts off). Watch the video for the explanation of why this is:
So stay tuned, we’ll be getting Charlie’s results really soon. But until we do, what kind of terrier do you see in him?
Good Dog: Studies & Research
Harvard study makes it official: dogs are good for us.
If you live with a dog, chances are you’re familiar with canine de-stressing techniques. Perhaps you’ve felt a wave of relief from burying your face in fur after a difficult day at work, or experienced a release of calming chemicals after being met with a particularly enthusiastic greeting. And maybe those daily dog walks have helped you shed a few pounds or led to some welcome social interactions with other people and their dogs. And doesn’t life seem to have more meaning because there’s a living creature depending on you?
To dog people, the emotional, physical and even spiritual benefits of canine relationships tend to be obvious. These benefits feel as real to us as the saliva-soaked tennis ball we’re holding in our hands. That’s why it can be so hard to understand why the non-dog world hasn’t caught on to all these life-altering advantages. Even worse is the fact that many people who have never lived with a dog seem to think we may be making all this up—that the only place these benefits exist is in our heads.
Science in Action
Thanks to a special report from Harvard Medical School (HMS), we now have something important to share with these nonbelievers—proof! Get Healthy, Get a Dog is the first publication to compile hundreds of research studies from around the world that document the physical and psychological benefits of dog ownership. Taken together, these studies provide the most complete picture yet of the many ways in which dogs enrich human life: from lower cholesterol and improved cardiovascular health to weight loss, companionship, defense against depression and longer lifespans.
“The most common reaction we’ve been getting from people about this report is that they are so grateful that someone has finally put into print what they’ve known intuitively all along,” said medical editor Elizabeth Pegg Frates, MD, who supervises the Lifestyle Medicine Interest Group at HMS, teaches a college course on lifestyle medicine at the Harvard Extension School, and directs the Wellness Programs at the Spaulding Stroke Research and Recovery Institute, an HMS affiliate.
The 50-page report is the result of a collaboration between HMS and Angell Animal Medical Center, a leading veterinary hospital based in Boston. Get Healthy, Get a Dog approaches the dog/human relationship as a two-way street, so half of it is devoted to the human—what the dog does for the person—and half is devoted to the dog—what the person should do for the dog. Frates tackled the former, and Lisa Moses, VMD, who heads the Pain Management Service at Angell Animal Medical Center, covered the latter, which includes sections on nutrition, exercise, training and responsible pet ownership. Moses also makes a compelling case for adopting a dog rather than going to a breeder or pet store.
“We didn’t want to create the impression that a dog is some kind of tool for achieving better health,” says Moses in explaining the dual focus. “We wanted to emphasize that it’s the relationship that provides these benefits—it’s not the pet. And for that relationship to develop and be sustained, you have to do your part.”
Doing your part often means going for walks in the rain, sleet or snow, at all hours of the day and night. In fact, one of the primary health benefits of owning a dog is that it boosts your activity level. There have been about a dozen studies conducted on the link between dogs and human exercise, including one that compared 536 dog owners with 380 non-owners. Those with dogs were found to be fitter, thinner and less likely to have chronic health conditions, such as high blood pressure and diabetes. A study in Missouri that paired public housing residents with certified therapy dogs for five 20-minute walks a week found that participants lost an average of 14.4 pounds without changing their diets. (The report points out that most weight-loss programs and anti-obesity drug trails can’t boast such good results.)
Of course, the fact that regular exercise helps people lose weight and get healthy isn’t exactly breaking news. The insights come from the critical role the dog plays as a fitness partner—offering everything from enthusiastic encouragement to obnoxious pestering. Unlike a human partner, a dog is not going to suggest ducking out to a movie. “The dog support was always positive, while the human support could be positive (friends, family), negative (saboteurs) or inconsistent,” wrote Frates. Another reason that people tend to adhere to an exercise program if a dog is involved is the perception that the dog needs them. In one study, 72 percent of participants cited this as the reason they stuck to the activity schedule for the full 50 weeks of the trial.
“Sometimes people find that the dog becomes the excuse for taking care of themselves,” says Moses. “It may not be acceptable to them to be so self-oriented, but if it’s about the dog, then it’s okay.”
The American Heart Association (AHA) uncovered another piece of canine magic: a dog appears to help someone who is obese overcome his or her embarrassment about being seen in public doing physical activity.
It’s likely that increased exercise plus the calming effects of dogs (which we’ll get to later) contribute to lowering blood pressure. One study actually tested dog ownership as a treatment for high blood pressure. Thirty people with borderline hypertension were randomly assigned to either adopt a dog right away or defer adoption to a later date. After five months, the segment of new dog owners experienced significant declines in systolic pressure (the top number, which measures the highest arterial blood pressure). The group that had been asked to defer adoption experienced these same declines once they had taken their new dogs home and spent time with them. In 2013, the AHA went as far as to say that pet ownership “is a reasonable strategy for reducing heart disease risk.”
And there’s more good news on the cardiac front. A study of nearly 6,000 men and women in Australia found that dog owners of both sexes had lower triglyceride levels than non-owners, and male dog owners also had lower total cholesterol levels.
Beyond these formidable physical benefits are the psychological ones, which according to Frates “are hard to overstate.” Dogs make us feel less isolated. They pull us into a social world inhabited by other people walking other dogs. (Seventy percent of dog walks lead to at least one spoken interaction with a stranger.) And they help us meet the basic human need for companionship. Two large, long-term studies that followed people from childhood to old age found that those who were more engaged with others—whether those others were people or animals—lived longer. Those longer lives may also be more purposeful. A dog’s total dependency can make that person feel wanted and give life a sense of meaning.
Moses knows this phenomenon first hand. Her grandfather spent more than a decade as primary caretaker for his wife, who suffered from rheumatoid arthritis and cardiovascular disease. During all those years, he had a succession of dogs to care for—or was it the other way around? After his wife died, his beloved Terrier mix Lady succumbed to kidney failure. “At age 92, unbeknownst to us, he went out and adopted another dog,” Moses says. “Having a dog was the reason he got up in the morning. It was his entire life. He was a living testament to the power of the human/canine bond.”
There are other indicators that dogs are particularly helpful to older people. The HMS report cites a year-long study from Canada that found elderly dog owners to be more capable of performing daily activities, such as dressing and feeding themselves. This is likely because in attending to their animal companions, seniors are reminded to take care of themselves. They also have a structure in place, thanks to the need for regular pet meal times and walks, which reinforces their own self-care habits.
At the other end of the age spectrum, children learn important life skills from early bonding with the family dog. That bonding can lead to stronger human connections later in life, according to a Tufts University study, which also found that kids who’ve forged emotional connections to dogs have more empathy, feel more self assured and do better in social settings.
“How else would you get your kids to touch and love something?” asks Frates, the mother of two teenage sons. “For boys especially in this culture, there are very few acceptable ways of encouraging this type of bonding and intimacy.”
There is even evidence that exposure to a dog from infancy onward reduces the likelihood that even the most allergy-prone kids will develop problems. Only 19 percent of babies living with dogs developed pet allergies, compared to 33 percent of babies who grew up in dog-free homes, according to one study.
As those babies grow up and become college students, the dog benefits continue. Several psychological studies have found that college-age adults tend to find more stress relief in turning to their dogs than in seeking comfort from parents or siblings. Still other adults were found to shake off the blues just by thinking about their dogs … which brings us to the magic of oxytocin.
Having a dog can be like having your own a prescription for oxytocin with unlimited refills—except that rather than dispensing this drug, your dog incites you to release it. Also known as the “love,” “bliss,” and “bonding” hormone, oxytocin inspires positive feelings. It helps stave off depression and limit the release of the stress hormone cortisol. You can get an oxytocin infusion by petting your dog, by laughing at the silly things she does, and even by looking into her loving eyes, a conclusion confirmed by recent study
Dogs also offer an alternative to meditation sessions and yoga classes when it comes to learning the Buddhist practice of mindfulness. Every dog walk is typically an exercise in experiencing the present moment: savoring an especially aromatic fire hydrant, having a satisfying roll in the grass or interacting with a new neighbor. Dogs put us more in touch with nature and help us put aside our worries about the future and regrets about the past to focus on the here and now.
While all the information contained in Get Healthy, Get a Dog has been meticulously reviewed and objectively compiled, Moses and Frates are hardly dispassionate observers. Both say their lives have been greatly enriched by their relationships with their dogs. They do, however, come from very different ends of the dog spectrum. Moses, who shares her home with a rescue named Rudy, describes her love of canines as developing “in utero.” This was due largely to the influence of her grandfather and the fact that he treated his Beagle mix, Friday, like one of the grandchildren.
Frates, on the other hand, was terrified of dogs after being bitten on the shoulder by a Doberman. The experience, which happened when she was eight years old, was so traumatizing that she spent the next three decades crossing the street to avoid close contact with a dog, even a little one. Finally, though, it wasn’t any particular dog who changed her mind, it was her commitment to health. As a physician specializing in lifestyle medicine, Frates thought she had all the bases covered—diet, exercise, meditation. But when she took a health and longevity quiz to determine her “real” age (as opposed to her chronological one), she was surprised that one of the questions concerned dog ownership.
Intrigued by the implications, she began to review the existing literature, much of which has been summarized in this special report. She also purchased a Goldendoodle she named Reesee, from a breeder in West Virginia. “Everything has been different for me since then,” Frates says, adding that she and Reesee are regular running buddies. “When we go running, she is so happy and I’m happy because she’s happy. You just appreciate the world in a much different way.”
Frates believes that if something like the Harvard Health Report had been available years ago, she would have explored the joys of dog ownership much sooner. Now, she hopes that the report will encourage other non-dog people to reconsider their position. “We’re hoping to encourage people to take the leap of getting to know a dog,” she says. “And perhaps we’ll also be able to encourage more dog adoptions—that’s a focus that Lisa brought to the project.”
That’s because the nonprofit Angell Animal Medical Center, where Moses works, is part MSPCA, the nation’s second oldest humane society, and has a very active adoption component. (Now that she realizes the situation for homeless dogs, Frates says she would adopt in the future.) Get Healthy, Get a Dog includes a section on “Adopting a Dog,” which provides information on determining the right breed for your home and suggestions on finding breed rescue groups and shelters. It also urges people to stay away from pet stores, where the dogs typically come from puppy mills.
Moses hopes readers will follow the report’s suggestions and reap the amazing benefits of dog ownership.
“Dogs are more important now than ever before,” she says. “Because people are living longer and so many live alone and don’t have kids. This is the moment for the human-animal bond.”
The report is available as a printed document, a PDF or both and can be purchased online at health.harvard.edu/staying-healthy/get-healthy-get-a-dog.
Dog's Life: Lifestyle
It bonds people and dogs
You gaze into your dog’s eyes. Your dog gazes back at you. It’s true love, right? Yes, absolutely! And it’s not just any kind of love, but perhaps one of the most powerful kinds of love that exists—the love between mother and child.
So says a new study published in the prestigious journal Science called ”Oxytocin-gaze positive loop and the co-evolution of human-dog bonds.” This research provides evidence that our feelings of love for dogs are mutual and are in part a result of looking into one another’s eyes, just like mothers and babies do to form their strong attachment.
In humans, it has been shown that mothers who spend more time in mutual gazing with their babies have higher levels of oxytocin. (Oxytocin is a hormone that plays a large role in the formation of social bonds as well as feelings of love.) Additionally, there is a positive feedback loop in humans. Mothers with higher oxytocin levels engage in more mothering behavior, which affects oxytocin levels in their babies. That in turn leads to higher levels of attachment, which increases oxytocin levels in mothers, leading to more maternal behavior, and so on.
The purpose of this new research was to investigate whether humans and dogs also have a positive-feedback loop in which oxytocin plays a role, and if so to learn whether gazing is a part of the process. In one part of the study, researchers measured levels of oxytocin in the urine of people and their dogs both before and after they interacted. They found that in pairs in which the dogs gazed at their guardians for a long time, levels of oxytocin rose in both the people and the dogs.
In the second part of the study, experimenters examined whether giving oxytocin to dogs affected their gazing behavior or the oxytocin levels of their guardians. Researchers gave oxytocin to dogs (intranasally) and observed that female dogs given this chemical gazed at their owners for longer periods of time than female dogs given saline as a control. (It didn’t affect male dogs the same way.) Even though they were not given oxytocin, guardians’ levels of this hormone increased after interacting with female dogs who had received it. Researchers are not sure why the behavior of female, but not male, dogs was affected by the oxytocin.
This research suggests that the bond we feel with our dogs is not only similar to the bond between mothers and children, but that the mechanism behind the connection is the same. This type of attachment between different species is rare and continues to interest scientists and dog lovers alike. It’s possible that the process of domestication of the dog was possible in part because dogs co-opted the social communication and social bonding process of babies.
Do you feel the love when you and your dog gaze into one another’s eyes?
News: Guest Posts
Ample data show dogs and other animals remember the past and plan for the future
A few days ago a colleague asked me if I'd seen an essay called "Dogs Don't Remember," published by Dr. Ira Hyman. I hadn't, and then, as I was doing an interview, a similar question about mental time travel by animals came up so I decided to pen a few comments about Dr. Hyman's claims that "Dogs don't remember what happened yesterday and don't plan for tomorrow" and "Even if they can't describe their memories,chimps may engage in mental time travel. My dogs, however, are stuck in an eternal present."
In his essay, Dr. Hyman also writes, "If I walk into the backyard, the dogs are overjoyed to see me and act like they haven't seen me for days. If I stay in the backyard, they quickly become bored with me. If I go inside and return after 10-15 minutes, my dogs are overjoyed to see me and act like they haven't seen me in days. They don't remember that I was in the backyard just a few minutes ago."
I don't see that dogs or other nonhuman animals (animals) greeting a friend(s) after a short absence says much about whether or not they remember that an individual(s) had just been there. Many animals engage in repeated and effusive greeting ceremonies when first seeing a friend and shortly thereafter. So too do humans.
What about future planning?
Given his interests in mental time travel, Dr. Hyman also writes, "Dogs don't plan for particular future events although they have a general expectation of when dinner will appear." He may be correct here. I don't know of any studies that show that dogs "plan for particular future events" but, for example, I have seen dogs and wild coyotes very cautiously approach an area where unfriendly individuals live and often have felt they were planning for possible combat. Nonetheless, I'll grant for now that it is difficult to differentiate planning for a particular event and having a general expectation that something might occur. However, I wouldn't be so sure that dogs don't do both until the proper studies are conducted.
Studies on nonhuman primates, birds, and other animals show, in fact, that they do remember the past and plan for the future. In an essay I wrote called "What Makes Us Uniquely Human?" that was concerned with mental time travel, I noted that the prominent primatologists Christophe and Hedwige Boesch-Ackerman wrote in their book The Chimpanzees of the Tai Forest that "A hunting chimpanzee 'not only has to anticipate the direction in which the prey will flee (recorded as a half anticipation), but also the speed of the prey so as to synchronize his movements to reach the correct height in the tree before the prey enters it (recorded as a full anticipation) . ... We also recorded a double anticipation when a hunter not only anticipates the actions of the prey, but also the effect the action of other chimpanzees will have on the future movements of the colobus, that is he does not anticipate what he sees (the escaping colobus), but how a future chimpanzee tactic will further influence the escaping monkeys." And, even birds remember the past and plan for the future (see, for example, "Can animals recall the past and plan for the future?" and for numerous examples of more recent research on a wide variety of animals please see).
There's no evidence that dogs are stuck in "an eternal present"
So, all in all, unless others and I are missing something, dogs do remember yesterday. If Dr. Hyman literally means by "yesterday" the preceding day—24 hours ago—perhaps he's correct. To the best of my knowledge, no animals other than humans look at or wear watches or use calendars. However, it doesn't seem that Dr. Hyman literally means yesterday, but rather, more generally, "the past," given the example he uses about dogs greeting him repeatedly even if he's only been absent for a short while.
There are many examples of dogs and other animals "remembering yesterday." Think of dogs and other animals who have been severely abused and who suffer from severe fear or depression for years on end, and also, for example, think of dogs who remember where they and others peed and pooped, dogs who remember where their friends and foes live, dogs who change their behavior based on what they learned in various sorts of learning experiments, and dogs who remember where they're fed and where they've cached food and other objects. The list goes on and on.
From an evolutionary point of view it would be somewhat odd and exceptional if mammals such as dogs and many other animals didn't remember yesterday and plan accordingly. Mental time travel truly is a very exciting field of research and I look forward to more studies that speak to the questions of how past experiences inform future behavior. And, as I mentioned above, there already are many detailed studies that show that mental time travel back to the past and ahead toward the future is not uniquely human.
Marc Bekoff's latest books are Jasper's story: Saving moon bears (with Jill Robinson), Ignoring nature no more: The case for compassionate conservation, Why dogs hump and bees get depressed, and Rewilding our hearts: Building pathways of compassion and coexistence.
This story was originally published by psychologytoday.com. Reprinted with permission.
Dog's Life: Lifestyle
Oxytocin improves dog performance
A new study in the journal Animal Cognition that reports that oxytocin increases canine responses to human social cues adds to the large number of known effects of this chemical. The more that oxytocin is studied, the more influential it seem to be.
All the articles that refer to oxytocin as “the love hormone” are simplifying to the point of distortion. Sure, levels of this chemical rise in the early stages of romantic love, but that’s just a small part of its role in our lives. Oxytocin is a biologically occurring molecule made of a short chain of nine amino acid acids that has strong effects on the body and on social behavior. Ever since a study roughly 20 years ago showed that it played a key role in the choice of a lifelong mate in the famously monogamous prairie vole, a series of studies have shown its key role in a number of species in trust and social interactions, including bonding. New human parents of babies show a rise in oxytocin, for example.
On the other hand, the moms out there experience other effects of oxytocin related to parenting, and those aren’t all so sweet and glorious. The same chemical that helps us love our babies also helps our babies enter the world and thrive in it. That’s because oxytocin is important for the production of contractions during childbirth and also for lactation to feed our infants.
>To make matters more complicated, oxytocin can make memories of negative social interactions more intense. So, again, “the love hormone” is really not a fair and complete way to describe its social function. Perhaps it’s more accurate to say that it focuses our attention on social information and gives us the ability to understand it at a deeper level. The recent study. “Oxytocin enhances the appropriate use of human social cues by the domestic dog (Canis familiaris) in an object choice task ” supports this view of this powerful biochemical.
The researchers who conducted this study investigated the effects of oxytocin on canine performance in an object choice test (OCT). In an OCT, a person gives a non-verbal, social cue to a dog to indicate the location of a piece of hidden food. Based on the dog’s response, it is possible to learn what cues are meaningful to dogs and which ones they can correctly interpret. Two common cues in OCT studies are pointing and gazing in the direction of the food. In this study, dogs and their guardians came to the test center twice, 5 to 15 days apart for a set of 40 OCT trials, 20 for each cue—gazing or pointing. On one visit, the dog was given an intranasal dose of oxytocin prior to the study and on the other visit, an intranasal saline control was given. The order of these two treatments varied between dogs.
The dogs who were given oxytocin first performed better in their first session than those dogs given saline during the first visit to the testing center. Effects were not as obvious in the trials involving gazing. In gazing trials, the dogs given oxytocin performed no better than if they guessed randomly where the food was hidden, while the dogs given saline first did even worse. Since previous studies have suggested that dogs actively choose to avoid locations that humans have gazed at, this research suggests the possibility that oxytocin counteracts that negative interpretation by dogs, and that they simply guess.
vious OCT studies, dogs have shown no improvement over time. Since learning occurred no matter which treatment dogs received first, it does not appear as though the oxytocin was responsible.
Maybe it’s the science geek in me who has always been fascinated by social behavior, but I’m just as thrilled with the idea of oxytocin as “the social information enhancer and clarifier chemical” as I ever was by the term “the love hormone.”
Dog's Life: Lifestyle
New research confirms that you are
Does your dog recognize you, the guardian, as unique in his life? Naturally, you consider him the most important, best, most special dog in the world, but does your dog view you as a unique treasure, or just as any old tall-two-legs capable of feeding him, putting on the leash, opening the door and playing with him?
A recent study in the journal Behavioural Processes titled “Dogs and their human companions: The effect of familiarity on dog–human interactions” investigated questions like these. Specifically, the scientists wanted to know whether dogs interacting with guardians, other people they know well and strangers behaved differently depending on how well they knew the person. With a series of tests on 20 dogs who were well socialized with some training experience, the researchers concluded that:
1. Dogs responded differently to the guardian and the stranger in most situations. That is, if your dog is like the family dogs in this study, you matter more to your dog than a stranger does. (Whew!)
2. Dogs acted differently when they were with their guardians and when they were with a familiar person when the situation involved playfulness, fear or anxiety, or physical contact.
3. Dogs reacted similarly to their own guardian and people that they knew well when the task involved responding to obedience cues.
Understanding the effects of the guardian on dog behavior is important because it informs us about the attachment between humans and dogs. It also matters because it shows that behavioral research is affected by which humans, if any, are present during experiments.
Dog's Life: Lifestyle
More evidence that dogs attend to human emotions
Science is subject to trendiness, just like fashion, language and entertainment are. So, just as we are all facing an abundance of mid-calf boots, abbreviations and post-apocalyptic films, there is no shortage of studies on the influence of human emotions on our dogs. One of the latest studies, Fetching what the owner prefers? Dogs recognize disgust and happiness in human behaviour, in the journal Animal Cognition, is just one of many recent works to explore this topic.
The purpose of this study was to address two questions: 1) Can dogs discriminate between human expressions that indicate happiness, disgust, and neutrality? 2) Do dogs prefer objects eliciting the more positive human emotion in the owner?
In this experiment, dogs had to choose between two bottles, each of which was associated with a human emotional expression of happiness, one of disgust or a neutral expression. The bottle associated with a more positive expression had food inside it while the other one contained a stone. (Though this is potentially a problem in the experimental design—the objects are not identical, meaning that the contents of the bottle as well as the guardian’s expression could be influencing the dog’s decision—the researchers conducted some control trials in an attempt to eliminate this potential glitch.)
The researchers measured dogs’ choices in two ways. They recorded which bottle the dog approached first and which they retrieved. They argued that positive emotions in humans may be linked with a corresponding emotion in the dog because what people feel positively towards—going for a walk, starting to play or dinnertime—may also trigger positive feelings in the dog. On the other hand, negative emotions in people may not correspond to the dog’s response to something. That is, when humans express disgust, it may be related to objects that dogs find appealing such as trash or poop. That’s why, in this study, the experimenters looked at a task (fetching) rather than just an approach to an object. They wanted to see how dogs responded to human requests rather than simply making a choice based on their own preference. The goal was to get a better measure of dogs’ responses to human emotions.
The overall findings of this study are that yes, just like in so many other studies recently, dogs are attuned to the emotions of their guardians. They preferentially retrieve the object associated with a more positive human emotion. So, when their guardian expressed happiness over one bottle and disgust or neutrality over the other bottle, they were significantly more likely to retrieve the bottle associated with happiness. Similarly, if their guardian expressed disgust over one bottle but was emotionally neutral about the other, the dog was more likely to retrieve the neutral bottle.
What I find most interesting in this study is that dogs preferentially retrieved the object associated with a more positive emotion even though they didn’t necessarily show a preference when measured as first approach. In other words, they acted according to human preference when told to do something—“Fetch!”— even though it was sometimes in contrast to their preference about which object to approach. We all know that dogs find many things appealing that revolt us. I’m personally thinking of how often I had to bathe my dog after he rolled in fox poop when I lived on a farm. I found it disgusting but it was clearly very appealing to him even with the threat of a bath hanging in the balance.
If the researchers had only looked at approach, they might have concluded that dogs could not discriminate between the various human expressions of emotion. Their more complex design provides evidence that dogs can do so, but that they don’t always behave accordingly.
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