The prevalence of allergies will explode by 2025 in western countries. Similarly, a survey from 2020 estimated that approximately 100 million (30%) Americans of all ages have allergies currently.
Multiple lifestyles and environmental risk factors have been proposed behind this explosion. These include increases in the use of broad-spectrum antibiotics, detergents, antiseptic soap, and cesarian births, as well as changes in the home, such as decreased ventilation, increased carpeting and furnishing, and increased temperature.
Another probable factor is the steady decrease in the time spent playing outside by children, resulting in less physical activity, a higher body mass index, shallower breathing patterns, less exposure to bacteria, and greater exposure to indoor allergens.
Among traditional farmers in Europe and North America allergies are less common, which suggests that their traditional lifestyle may be a protective factor against the development of atopic diseases.
In a new study, researchers collected breast milk from 52 mothers with babies between two weeks and six months of age in the community of old order Mennonites of Penn Yan, New York, and from 29 mothers with a modern urban lifestyle in the nearby city of Rochester.
They used questionnaires and follow-up phone calls to ask moms about their lifestyle and environment, and whether they or their babies had any symptoms of atopic diseases.
They then measured the milk’s concentration and activity of IgA antibodies, which are important for protecting the respiratory system and gut against microbes as well as the concentration of oligosaccharides, cytokines, and metabolites of fatty acids.
They also used ribosomal RNA gene sequencing to determine which species of bacteria were carried from mother to baby in milk.
Old order Mennonite mothers self-reported a greater exposure to farm animals, dogs, unpasteurized farm milk, and barns, a higher rate of giving birth at home, more frequent use to bleach to sterilize the home, and a lower exposure to antibiotics and pesticides.
They also reported a lower rate of atopic diseases for themselves and their babies. The breast milk from the old order Mennonite mothers contained more IgA1 and IgA2 antibodies against peanut, egg ovalbumin, dust mites, and the bacterium Streptococcus equii, a pathogen of horses.
The milk from Mennonite mothers also contained milk microbes, such as bacteria from the families Prevotellaceae, Veillonellaceae, and Micrococcaceae, and higher concentrations of certain oligosaccharides and fatty acids.
These findings indicate that women on such traditional farms generate immunity through long-term exposure to farm animals and foods such as unpasteurized farm milk and eggs. The results also suggest that babies can acquire some protection against allergic diseases through their mother’s milk.
Source: Medindia
