Your best friend could be your key to a healthy immune system

If you are like 105 million other Americans, you know many of the benefits (as well as some of the frustration) that come from owning a dog.

Exercise from taking them for walks, companionship when you are lonely, or just the joy of watching their silly antics are just a few of the attributes that earn dogs the title of best friend. But there has been some interesting research recently that shows dogs may actually do more than just provide you with a reason to exercise, get up in the morning, or laugh.

They may actually help boost your immune system in much the same way as probiotics work. Read further to find out how your furry pal that steals all the bedcovers at night and hogs the entire couch might actually also keep you healthy.

Changes in immunity with the industrial revolution

As you might already know, the body can acquire a natural immunity if it is exposed to a low level of certain pathogens. One of the more interesting theories that came out of this acquired immunity is what is known as the hygiene hypothesis.

In a 2000 paper in the journal Thorax, a researcher proposed that some of the more significant changes in home environments that happened as a result of the Industrial Revolution actually reduced our exposure to microbes and pathogens which might provide this immunity.¹

Other changes occurred in the post-industrial age that further reduced natural immunity in home environments, including living further separated from farmlands, particularly those with barn animals such as cows, horses and goats. Several studies have shown that children raised around barn animals have a stronger immunity against both hay fever and allergies than children not raised in such environments.

Researchers theorize that the difference may be that there is a greater concentration of these microbes and pathogens around farm animals and barns.^2,3

Combine this with an increased emphasis on cleaning the home environment, as well as greater time spent indoors, and the end result is an indoor environment that doesn’t support providing natural immunity through exposure to low levels of pathogens and microbes. These two articles are part of a growing research area of what are known as indoor microbiomes, or indoor microbes and pathogens.

How your dog can help protect your immune system

As noted above, one of the main reasons for both the increase in asthma and the decrease in “good” indoor microbes and pathogens has been industrialization, which has separated most people from the natural environment, including the farm animals that carry these microbes and pathogens.^1-3

While it is highly impractical to keep Buttercup the cow as a pet if you live in a high-rise apartment, Fido the dog can provide many of Buttercup’s immunity benefits, but without the size drawbacks.

A 2015 article from the Proceedings of the Royal Society B [Biology] reported the findings from testing dust samples of from inside and outside 1,200 homes across the U.S. The goal was to look for the differences between the samples in terms of microbe diversity, based on a variety of factors, including the presence or absence of pets.⁴ T

he findings showed that the presence of pets inside the house, regardless of region, led to greater diversity in indoor microbiomes. However, the presence of dogs showed as many as 56 additional classes of bacterial species in the indoor environments, while cats only accounted for 24 species. In essence, having a dog—or, to a lesser degree, a cat—can provide a greater variety of potentially helpful microbes to help boost your immunity.⁴

The nose knows

The explanation for this is pretty simple, if you consider how dogs interact with their environment. They use their keen sense of smell to discover the world around them. This invariably means that they will pick up a wide variety of microbes and pathogens just by being taken on a walk. They will roll around in the dirt, sniff at bushes and trees, and smell other dogs that they meet.

During this process, they will pick up various microbes and pathogens that are naturally present outside and then bring them back into your house. In essence, your dog acts as a vector for allowing a wider variety of microbes and pathogens into your house, which may help boost your immunity.

There are many great benefits that come from having a dog in your life. It now appears that they may be even more beneficial to your well-being than originally thought.

References

Strachan DP. Family size, infection and atopy: The first decade of the “hygiene hypothesis.” Thorax. 2000;55(Suppl 1):S2-S10. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1765943/

Von Ehrenstein OS, Von Mutius E, Illi S, et al. Reduced risk of hay fever and asthma among children of farmers. Clinical & Experimental Allergy. 2000 Feb;30(2):187-93. https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1365-2222.2000.00801.x

Stein MM, Hrusch CL, Gozdz J, et al. Innate immunity and asthma risk in Amish and Hutterite farm children. NEJM. 2016;375(5):411-421. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5137793/

Barberán A, Dunn RR, Reich BJ, et al. The ecology of microscopic life in household dust. R. Soc. B. 2015 282 20151139; DOI: 10.1098/rspb.2015.1139. Published 26 August 2015. http://rspb.royalsocietypublishing.org/content/282/1814/20151139