Dr. Conway McLean, Journal columnist

The phrase “man’s best friend” immediately brings to mind positive feelings for most of us. The reference is, of course, to the genus ‘Canis’, aka canines, more popularly known as dogs. Everyone has a dog story or two. For a few, thoughts of these furry beasts evoke fear, but most people experience warmth and fond memories. Dog ownership is extremely common in the US, so nearly all Americans have had very personal contact with our four legged friends.

The origins of dogs date back to domesticated descendants of the wolf. We are uncertain when this first occurred. One study claims they were tamed as far back as 30,000 years ago, while others state this occurred during the Neolithic age (12,000 years ago) in Europe. Regardless, there is no question they have been, as a species, tremendously successful. It is believed there are approximately 78 million dogs in the United States (who are pets), while the global dog population is about 987 million. For the most part, this is because of their affiliation with humanity.

The bond between the two has been a topic of conjecture and exploration for years but there is no denying it is unique. The role of dogs in the lives of mankind has gone through vast changes over the course of human history. Early on, their benefits to the hunter-gatherers included keeping us and our dwellings safe, guarding us and our cattle. Dogs have also been trained to assist with hunting.

In modern times, dogs are primarily valued for their companionship, famed for their loyalty and their dedicated love of their owners. Their almost supernatural ability to elicit positive feelings has led to various uses of this talent. The use of seeing eye dogs is well-established and began in the 1920’s but a newer use of our four-legged friends is as therapy dogs. Animal facilitated therapy, referred to as AFT, is considered a form of complementary and alternative medicine (CAM) because it complements and adds to other established treatments.

Animal-assisted therapy has been shown to reduce pain, anxiety and fatigue in people with numerous health conditions, everything from dental procedures to cancer treatments. Dogs have a calming presence. Therapy dogs have been used with great success in long-term care facilities, as well as with veterans with post-traumatic stress disorder. One study looked at the effect of these therapy dogs on the pain levels experienced by patients after total joint replacement and found these people reported less pain with decreased requests for pain medications. But it’s not just the patients who benefit. Even the family members of these patients say they feel better when they attend these visits.

Therapeutic dog visits are also being used in nonmedical settings, such as community centers, to help people deal with anxiety and stress. Further evidence of their beneficial effect is in the treatment of depression. They clearly have the ability to help people in stressful situations feel better. One way they do this is by stimulating the release of oxytocin from humans, a substance sometimes referred to as the “love hormone.”

One of the characteristics for which dogs are well known is their sense of smell. Dogs have extraordinary olfactory sensitivity. They can detect even minute amounts of a particular odor, with an olfactory sense estimated by some to be one million times more effective than humans. Dog’s ability to detect certain molecules is possible because of specific anatomic features, like the huge number of olfactory receptors they possess. These and other characteristics give dogs an extraordinary olfactory sensitivity to even minute amounts of any particular odor.

This ability may explain a canine skill only recently making the headlines. Although the specific mechanisms have not been elucidated, studies have revealed some dogs can detect some types of cancer, including breast, lung, prostate, and colon. It would appear dogs can do this from a variety of samples such as breath, urine, plasma, and blood. Research studies have sufficiently demonstrated this ability to say this is a real and demonstrable phenomenon, not a fluke or accident. The benefits of the early detection of cancer are significant, especially reducing the need for more aggressive treatment, decreasing the spread of cancer, and improving overall survival.

Of course, there is still the question of what do we do with this knowledge? How do we put this talent of some canines to detect cancer in people, into practical, real-world methods. Should we train a dog army to be deployed to hospitals? Actually, believe it or not, efforts are being made to do just that.

Turns out there are other benefits. Research suggests that children who grow up in homes with pets are less likely to develop allergies. The theory is microbial exposure in infancy may help protect children against later allergies and asthma. Studies suggest early exposure to pets when the immune system is maturing is associated with a reduced risk of asthma. The hygiene hypothesis of allergy and asthma development, which posits that exposure to germs in childhood helps strengthen the immune system, thereby reducing the risk of childhood allergic diseases.

Need more? Dogs can detect epileptic seizures before they happen, as much as 45 minutes before the siezure occurs. Apparently, it’s all in the nose. Dogs amazingly sensitive olfactory sense allows them to detect certain substances released by the human body in the process of having a seizure. The benefits are obvious, one being it could give people time to take appropriate medication, or get to a safe place. Enough studies have been done: this is a real and demonstrable phenomenon.

Dogs make people feel good……this much is clear. Numerous studies have indicated having dogs as pets is associated with better physical health. Often, they improve their owner’s activity levels by forcing them to take a walk. Perhaps this explains why dog owners have a lower risk of heart disease. But regardless of the mechanism, dog ownership is healthy. Am I objective? Not in the least, having three myself and considering them a highly honorable and noble species. Man’s best friend indeed.

Editor’s note: Dr. Conway McLean is a physician practicing foot and ankle medicine in the Upper Peninsula, with a move of his Marquette office to the downtown area. McLean has lectured internationally on wound care and surgery, being double board certified in surgery, and also in wound care. He has a sub-specialty in foot-ankle orthotics. Dr. McLean welcomes questions or comments atdrcmclean@outlook.com.