Owning a cat or dog may protect children from developing food allergies

FUKUSHIMA, Japan — Having a family cat or dog protects young children against food allergies — even before they’re born, a new study reveals. Researchers in Japan note the number of kids seeking treatment for allergies is soaring in recent years, with more than one in 10 now having a problem. As doctors struggle to cope, the new report finds pets could help solve the problem, reducing allergy risks by around 15 percent.

Children exposed to dogs were less likely to experience egg, milk, and nut allergies specifically. Cases of egg, wheat, and soybean allergies dropped among their peers who lived with a cat.

“Continued dog and cat exposure from fetal development to infancy was estimated to reduce the incidence risk of food allergies,” says lead author Dr. Hisao Okabe of Fukushima Medical University, in the journal PLoS ONE.

The findings are based on an analysis of over 65,000 infants from Japan tracked until they were three years-old. The team assessed the prevalence of food allergies based on a parent-reported doctor’s diagnosis.

“The hygiene hypothesis suggests pet exposure is effective in preventing allergic disease, and some studies have reported the beneficial effects of dog exposure during fetal development or early infancy on food allergy,” the researchers write. “This study aimed to explore the effect of exposure to various species of pets on the risk of food allergies.”

food allergies
The graph displays associations between exposure to various species of pets during fetal development (pink dots) or early infancy (teal dots) and the incidence risk of food allergies in children up to 3 years old (confidence intervals on bars in light pink). Exposure to indoor pet dogs during fetal development and/or early infancy was associated with reduced risk of egg, milk and nut allergies (adjusted odds ratios < 1), whereas cat exposure was associated with reduced risk of egg, wheat and soybean allergies. CREDIT: Anne-Lise Paris (www.in-graphidi.com), PLOS, CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/)

What’s causing allergy cases to rise?

A leading theory behind the rise in allergies is the “hygiene hypothesis.” Living conditions in much of the world might be too clean. Germs train immune systems to tell the difference between harmless and harmful irritants. In countries like the United Kingdom, allergy rates are some of the highest in the world. While prevalence of hay fever and eczema has plateaued or decreased, hospital admissions for acute reactions to foods have increased significantly.

Pet exposure may combat food allergies by boosting the microbiome. Previous studies indicate that our pets increase good bacteria, making children less vulnerable.

“These findings reduce concerns about the development of allergic diseases caused by keeping dogs and cats,” study authors explain. “Reducing the incidence of food allergies will significantly reduce childhood mortality from anaphylaxis.”

About 22 percent of the participants were exposed to pets during the fetal period, most commonly dogs and cats. Among children exposed indoors, there was a significantly reduced incidence of food allergies, though there was no significant difference for children in households with outdoor dogs. Perhaps surprisingly, children exposed to hamsters (fewer than one percent of the total group) had significantly greater incidence of nut allergies.

Dog kissing cute little girl
(© fizkes – stock.adobe.com)

Pets could reduce the burden of medical costs for allergies

The data was self-reported and supplemented by medical record data gathered during the first trimester of pregnancy, at delivery, and at the one-month check-up. The results may help guide future research into the mechanisms behind childhood food allergies.

“Incidence of food allergies in children has increased over the past few decades, reaching more than 10 percent in developed countries,” researchers write. “Food allergy is a condition that reduces the quality of life of patients and their families, imposes a significant medical cost burden, and is a major trigger of anaphylaxis, which is sometimes fatal.”

“Therefore, preventing its occurrence is a key priority. The notion that early-life exposure to pets or older siblings provides an immunological benefit to human health stems from the hygiene hypothesis, first proposed in 1989 and subsequently supported by several epidemiological studies,” the team concludes.

“Pet exposure has been suggested to be effective in the prevention of allergic diseases. However, in some developed countries, including Japan, families concerned about allergies continue to avoid owning pets.”

South West News Service writer Mark Waghorn contributed to this report.

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