Topline
Children growing up with cats and dogs are less likely to develop food allergies later in life, Japanese researchers have found, building on previous research into a growing and potentially life-threatening problem and signposting possible ways to treat or prevent the deadly reactions in the future.
Some pets are linked with lower rates of food allergies.
Key Facts
Children who were exposed to pet cats or dogs during early infancy or fetal development were far less likely to develop food allergies than their petless peers, according to a study published in PLOS One on Wednesday.
The study, which the researchers said is the largest of its kind, examines the rate of numerous food allergies and exposures to different pet species from data covering more than 66,000 infants until the age of three years old.
Kids growing up with indoor dogs were significantly less likely to develop food allergies than those who did not, the data showed, particularly egg, milk and nut allergies.
Allergy rates were not significantly different among the kids who grew up with dogs kept outside, the researchers found.
Cat exposure also appeared to slash the risk of developing food allergies, the researchers found, especially egg, wheat and soybean allergies.
While the finding supports other research suggesting a link between allergies and exposure to pets in early life, Dr. Hisao Okabe, a pediatrician at Fukushima Medical University and one of the study’s authors, told Forbes it was surprising to discover the link might change depending on pet species and food allergen.
Big Number
4 million. That’s around how many children in the U.S. have food allergies, according to CDC research, almost 6% of all children. Food allergies were more prevalent among Black children (7.6%) compared with white (5.3%) and Hispanic (5%) children. Around 16 million adults in the U.S. also have food allergies, the CDC estimates. Food Allergy Research and Education, a non-profit organization, estimates there are around 200,000 hospital visits due to food allergies each year.
What We Don’t Know
Rates of allergies, including food allergies, have been ticking upwards for decades and researchers do not know why. A popular idea, often called the hygiene hypothesis, is that our cleaner environments have somehow made us more vulnerable to allergies by reducing our exposure to the things that cause them early in life. Scientists have proposed a number of possible explanations for why this could be the case, including how the human immune system reacts to animal microbiomes—the community of microorganisms animals, including humans, carry around with them—exposure to allergens through the skin and a greater reservoir of allergens in the air and environment of homes with pets. Data also suggests pet exposure in infancy reduces rates of multiple conditions with an allergic component—including food allergies, eczema, asthma and hay fever. This study was observational and did not investigate how, or if, exposure to pets changes the development of allergies, but it lends support to the theory.
Surprising Fact
Not all pet exposures appeared to reduce the incidence of food allergies in kids. Children exposed to hamsters, who made up less than 1% of those included in the study, had a notably higher rate of nut allergies than hamsterless children, the researchers found. Hamsters feed on nuts and Okabe told Forbes the finding suggests exposure to hamster food through the skin—which could sensitize infants to nut allergens—could possibly explain the increased rates of allergies. Further research will be needed to know for sure, Okabe said, adding that hand washing and keeping the “pet away from babies might minimize the risk of food allergy caused by pet food.”
Crucial Quote
Okabe told Forbes the researchers hope their work will help clarify how pet exposure helps cut the instance of food allergies and will one day “contribute to new food allergy prevention and treatment strategies.”
What To Watch For
The discovery that different pet species are linked to different types of allergy suggests an animal’s “unique gut” microbiome could be involved, Okabe said. Further research will be needed to verify this, Okabe stressed, adding that the team doesn’t think this means “exposure to a wider variety of animals as possible” is necessarily preferable.
Tangent
The researchers also studied food allergies among kids exposed to birds and turtles in infancy. The data was not strong enough to be statistically significant or make any firm claims on either animal for any food allergen studied. While further research would be needed to verify and produce a statistically useful result linking the species and allergy, the data suggested higher rates of soybean and nut allergies among kids exposed to turtles in infancy and higher rates of nut and egg allergies among kids exposed to birds.
Further Reading
What They Aren’t Telling You About Hypoallergenic Dogs (Atlantic)
The more pets you meet as a baby, the lower your risk of allergies (New Scientist)
Food allergies are on the rise—but new treatments are on the horizon (National Geographic)
