Farm life linked to more protection against allergies in breastfed infants

Milk from Old Order Mennonite mothers contained higher levels of antibodies against allergens compared with that of mothers in urban and suburban Rochester, New York, according to a cross-sectional study in Frontiers in Immunology.

“Old Order Mennonite lifestyle corresponds to that of about 100 years ago,” Kirsi M. Järvinen-Seppo, MD, PhD, chief of pediatric allergy and immunology and the founders’ distinguished chair in pediatric allergy at University of Rochester School of Medicine and Golisano Children’s Hospital, told Healio. “It may be the case that composition of human milk has changed over time. This may in part be responsible for the increase in allergic diseases.”

Studies have suggested that living on farms confers a reduction in risk for asthma and allergies. Because human milk oligosaccharides (HMOs) and microbiota help build infants’ immune systems, Järvinen-Seppo and colleagues aimed to identify whether the traditional farming lifestyle of Old Order Mennonites and urban and suburban living differently impacted milk content.

Researchers analyzed the composition of milk samples from 52 Old Order Mennonite mothers from western New York and 29 urban and suburban mothers from Rochester, New York, whose infants were aged 2 weeks to 6 months. To determine whether atopic disease was possible or likely in these infants, researchers conducted screening and follow-up phone surveys.

Old Order Mennonite mothers self-reported significantly lower rates of allergic rhinitis, atopic dermatitis and food allergies compared with Rochester mothers. They also had higher exposure rates to farm animals, dogs, farm milk and barns; more often used bleach; and had lower exposure to pesticides and perinatal antibiotics.

Although total immunoglobin A (IgA) levels were similar between groups, IgA₂ to dust mite (P = .04), peanut (P = .02) and egg ovalbumin (P = .02) was significantly higher in Old Order Mennonite milk. Old Order Mennonite milk also had significantly higher IgA₁ levels to Streptococcus equis (P= .002), a horse respiratory pathogen, and significantly lower levels to Enterobacter cloacae (P = .01), a gut commensal.

Kirsi M. Järvinen-Seppo

“These findings could be attributed to specific antigenic exposures between the Old Order Mennonite and Rochester mothers, for example, the higher levels of egg-specific IgA could reflect that eggs are a staple in their daily diet of the Old Order Mennonite who commonly keep chicken; however, elevated antibody levels against milk of cows or peanut are hardly due to more common exposures in the Old Order Mennonite,” the researchers wrote.

The human milk cytokines interferon (IFN)-lambda 3 (P = .03) and transforming growth factor-beta 2 (P = .04) were higher in Old Order Mennonite milk. In multivariate analysis, IFN-lambda 3 was significantly higher and soluble tumor necrosis factor receptor-1 was significantly lower in Old Order Mennonite milk.

“The cytokines measured here are of special interest, because we had previously identified those in higher concentrations associated with protection against food allergy,” the researchers wrote. “It may therefore be plausible that milk cytokines and IgA function in concert to support the infant against immune-mediated diseases.”

Old Order Mennonite milk also had significantly higher levels of certain HMOs, including lacto-N-neotetraose (P = .02) and difucosyllacto-N-tetrose (P = .05), and two long-chain fatty acids — stearic acid and tricosanoic acid — compared with Rochester mothers’ milk. In multivariate analysis, maternal antibiotic use correlated with the levels of multiple HMOs.

Rochester infants were more likely to develop atopic disease by 3 years of age. Researchers found lower milk concentrations of thymic stromal lymphopoietin (P = .002) in mothers with infants with atopic disease, whereas total higher levels of IgA (P = .000015) and IgA₂ to dust mite (P = .0001) were associated with protection against atopic diseases.

“We were surprised to see that there were many differences in the composition of immunologically active factors, bioactives and microbiome between farming lifestyle and urban/suburban mothers,” Järvinen-Seppo told Healio.

Because the study was limited by small sample size, self-reported allergic outcomes and nonassessment of other factors in atopic disease development, the researchers suggested larger longitudinal studies are necessary to understand the impact of pre- and postnatal maternal factors on allergic disease development.

Reference:

Breast milk from Mennonite moms on farms may better protect babies from allergies. https://www.newswise.com/articles/breast-milk-from-mennonite-moms-on-farms-may-better-protect-babies-from-allergies. Published Oct. 11, 2021. Accessed Oct. 22, 2021.

For more information:

Kirsi M. Järvinen-Seppo, MD, PhD, can be reached at kirsi_jarvinen-seppo@urmc.rochester.edu.