Study Shows Exposure to Animals in Early Childhood Supports Immune Development

By Christina Lavers | Wake Up World

Is Urban Living Making Us Sick?

The last century, especially the last several decades, has seen a steep rise in levels of allergies, asthma and auto-immune disorders. What is interesting is that statistical analysis shows that typically these conditions are more prevalent in developed nations than in developing countries, and when families migrate from a developing country with a low incidence rate to a developed one with a high incidence rate, it only takes one generation for the conditions to present.

A recent study from the University of Eastern Finland suggests that exposure to farm animals in early childhood may play an important role in the development of a healthy immune system, specifically in regards to the role of dendritic cells and cytokine production. Dendritic cells are messengers that present antigens to other cells to elicit an immunological response. Via this mechanism, they regulate cytokine (messenger protein) production, adaptive immune system response, and are essential for the establishment of immunological memory.

Many studies have noted that children who grow up around farm animals are less likely to develop childhood atopic diseases (like asthma and eczema). However, though a clear relationship could be found between growing up on a farm and the development of a healthy immune system, the mechanistic link between the two was unclear. This study attempted to understand the link.

Related Article:Dr. Linda Bender on Our Connection to Animals

Heidi Kaario, MSc, in her PhD thesis investigated whether farm and pet (cat and dog) exposure affect the phenotype and functional properties of dendritic cells along with cytokine production in peripheral blood mononuclear cells of children at the age of 4.5 years in a subpopulation of a wider study, known as the Finnish PASTURE birth cohort study. Half the children in the study were from farming families and the other half were from rural, non-farming families.

The study found a lower percentage of dendritic cells in the peripheral blood mononuclear cell cultures of farm children as compared to those of non-farm children, when there was stimulation with lipopolysaccharide. The unstimulated peripheral blood mononuclear cells of farm children produced more, in particular, non-allergic Th1-associated and regulatory (non-inflammatory) cytokines than those of their non-farm counterparts. The implication is that introducing children to foreign but benign animal cells and animal-associated bacteria promotes optimal immune system regulation, making their bodies less likely to overreact to allergens, and less likely to confuse ‘self’ with ‘other’. Thus, immune system modulation guards against chronic inflammation, inappropriate or exaggerated immune response, and the development of autoimmune conditions.

While this study takes us a step closer to understanding the complex mechanisms involved in the development of our immune systems, it also reinforces the idea that our concept of hygiene might be flawed and that nature, rather than a strictly scientific approach, might be the way towards a solution.

The Germ Theory

In 1846 a Hungarian doctor named Ignaz Semmelweis noticed that if doctors washed their hands before delivering babies, the death rates for both mothers and infants went down. At the time Semmelweis had difficulty convincing others of his findings. He was eventually fired and ultimately condemned to a mental hospital where he himself became infected by a deadly strain of bacteria.

However, though he was not acknowledged in his time, today his assertions are seen as the first step on our long and still incomplete journey towards understanding the true nature of our complex relationship with bacteria.

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