Dirt Is GOOD – Why Children Need More Exposure To Germs

Photo – AntonioEsposito – pixabay.com

Parents of today’s millennial generation may have made a big mistake that comes under the general moniker overparenting. Micromanaging your kids’ living environment is now thought to be a potential a burden to them – with overprotection becoming a detriment to the development of their immune system. But how? A book published in 2017 by Jack Gilbert and Rob Knight focuses on the importance of allowing your kids to literally “play outside in the dirt”, which can help boost their immunity in the long run.

Gilbert and Knight emphasize how exposing your child early on to germs actually trains their immune system, particularly their neutrophils (a kind of white blood cell), to respond quicker and more effectively to similar pathogens in the future. On the other hand, children who are raised in overly clean environments have “hyper-sensitized” immune systems. People who weren’t exposed to germs as children often easily get sick or have their immune system “overreact” to a simple pathogen. ^[1]

Another example of natural bacteria at work concerns the health of children who were born vaginally versus via caesarian section. Studies have shown that children who are born vaginally are exposed to the natural bacteria in the vagina and therefore go on to develop stronger immune systems. Biasucci, et. al. concluded that microbial stimulation in infancy greatly affects a child’s immunity as they grow older, which he linked to how a child is delivered. ^[2]

Channel News Asia published a commentary in August 2017, highlighting the same thing as Gilbert and Knight: exposing your children to dirt boosts their immune system. According to Bever and Ng’s report, parents are mostly preoccupied with avoiding exposing their kids to viruses – but viruses are typically transmitted between people; they aren’t found in the dirt. Most microorganisms found in your local playground or park are rarely harmful and mostly benign. The report mentions studies conducted in Europe that revealed a lower prevalence of allergic diseases in rural areas compared to urban areas. This may be linked to how children in rural areas are “exposed to more dirt and germs” compared to children who were raised in the city. ^[3]

The Hygiene Hypothesis

In 2012, Umetsu published an article on The Hygiene Hypothesis, which was originally formulated by Strachan more than twenty years ago that aimed to explain the sudden increase in allergic disease in asthma over the past few decades. Umetsu cites an experiment conducted by Blumberg (which explains The Hygiene Hypothesis), wherein mice raised in sterile environments were “more likely to develop experimental colitis and… allergic asthma.” On the other hand, mice that where exposed to bacteria developed better immunity. Blumberg emphasizes that exposure was only beneficial to young mice, not adult mice. This suggests that if we don’t expose our children to germs early on, they may never be able to develop good immunity as adults. ^[4]

Over the years after Blumberg’s study was published, research was done on iNKT cells (or natural killer cells, which are part of the immune system) and their relationship to the occurrence of colitis and asthma. It is suggested that people who are not exposed to germs as children develop “larger” iNKT cells, which are quick to react to pathogens and irritants – thus predisposing a person to colitis and asthma. ^[4]

As parents, keeping our children safe is our number one priority. However, science tells us to draw a line; the way we protect our children may be actually hindering their growth and development. So the next time your child asks to play outside, don’t think too much about it and let him or her go. Remember, dirt is good!