organized curiosity

Improving health care through research

The One Time My Mom Was Wrong

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When I was growing up as the second oldest of ten kids, we didn’t have dogs or cats. My mother always said she had enough kids and didn’t have time to take care of a pet. My mom did allow us to have turtles. I guess she figured they were easy enough to care for. If I remember right we changed the water once every three days. Our turtles were in a small circular plastic container with a ramp that the turtle could come up on and a beautiful green plastic palm tree. We fed our turtles raw hamburger.

In most respects, my mom was a genius.  She taught me most of what I know and kept all of us from killing each other. But she was not right about pets. Dogs and maybe cats are good for our health. Turtles are bad.

Turtles are bad because they are an infective reservoir for salmonella, a very nasty bug that can kill. Apparently Agriculture Canada banned importation of small turtles into Canada in 1976. The turtles that I remember were actually red-eared sliders (Trachemys scripta elegans).  Unfortunately for the turtles, my brothers and sisters and I led to the demise of many of these cute creatures. None of us ever had a serious infection from them, although I am sure we did not wash our hands each time after touching them.Now what about dogs and cats?

There are several reasons certain pets are beneficial,   but first I must disclose a conflict of interest. We currently have both a cat and a nine-month-old standard poodle. Murphy, our poodle, is energetic and a real help in me getting my 12-15,000 steps a day. I walk him in the morning, usually about three thousand steps and then my wife and I usually walk the waterfront, about 4,500 steps.

There is good scientific evidence that having a dog can help you get moving. But not everyone who owns a dog walks it and aggressive dogs in a community can inhibit walking by non-dog owners. Most cat owners don’t walk their cats and sitting with a purring cat on your lap may make you feel loved, but it won’t help your activity level. The literature on the effects of dog and cat ownership on depression is mixed. In some studies, cat owners had more depression and death following cardiac events.  I certainly understand this. They must have had a cat like our cat. Maska tries to bite me when I try and pet her.  .

The American Heart Association did a very thorough review of pet ownership and cardiovascular health. They found that pet ownership especially dog ownership was related to better heart health. But they cautioned that the evidence is not strong enough to get a dog for that reason. Unsupervised and especially roaming dogs are a risk and a particular challenge in some communities especially  in remote areas of  Canada.

Dogs are also great for meeting people. Every day, a half dozen people want to say hello to the dog. Actually, very, very few of them want to get to know me.


But the evidence that I like best is that dog and cat ownership may strengthen the immune system and reduce allergies. The evidence for dog ownership is that dogs do not increase the risk of allergic response and may even prevent allergies.  For cats, some studies find an increase in allergies and some studies find a decrease. As someone who suffers from animal allergies, we chose a poodle and a Devon Rex cat because they provoke my allergies less.

This finding fits with other research and the “hygiene hypothesis” which I like to call the dirt hypothesis. The hypothesis is that some microbes especially those that co-evolved with humans may be protective against many autoimmune disorders from inflammatory bowel disease to multiple sclerosis. I like to interpret the research data more broadly to suggest that a clean house is a sign of a wasted life. My wife concurs that I have not wasted my life.

Editorial note:  There may be selective citation of scientific literature about cats and housework by Dr. McGrath to justify his proclivities.

~Dr. Patrick McGrath


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