Tom Sokolowski |
According to the hygiene hypothesis children develop healthy immunity by exposure to bacteria in their surroundings and the modern tendency in the industrialised world to keep children away from the dirt, thoroughly wash and sterilise everything they might come into contact with and overuse antibiotics (as well as eating produce from animals routinely fed antibiotics) has contributed to the rise of autoimmunity and allergy – signs of an imbalanced immune system.
Indeed some Inflammatory Bowel Disease (IBD) sufferers are deliberately consuming ‘parasitic’ worms in an attempt to bring their condition under control after the absence of IBD was noted in the so-called ‘developing’ countries where infection with helminths (worms) is the norm. IBD has become common enough that you probably know one or two people who suffer with the two most common forms – Crohn’s disease and Ulcerative colitis. So maybe we should no longer be calling these helminths ‘parasitic’ but ‘symbiotic’, since they seem to be conferring some benefit to us.
It has been long established that a healthy gut flora unperturbed by antibiotic use reduces the risk of allergy and autoimmunity and new research is investigating the links between poor gut flora and obesity, type 2 diabetes, Alzheimer’s disease and other chronic degenerative conditions typical of the modern post-antibiotic era.
A new study shows that more allergies develop in children whose households feature a dishwasher.
However, this is a classic case of ‘correlation not causation’. By this I mean that it might not be the dishwasher itself that causes allergies, but that families who own a dishwasher may have some other tendencies that could be the cause. For example they may be more hygienic in general or they may have less awareness of the toxicity of household products such as cleaners and pesticides.
That the study authors speculate the cause is to do with dishwashers killing more bacteria on the plates shows how the hygiene hypothesis has garnered the respect of the scientific community. This is indeed a likely cause but please take note that hay fever did not exist before the industrial revolution.
I do not believe this is because the first case of hay fever, reported in the early 1800’s, was due to excessive hygiene, but because of the role toxins also play in the development of allergy. Both toxic exposure (even in utero) and most likely a sterile environment predispose towards allergy and autoimmunity (amongst other factors, such as genetics).
So the increased prevalence of allergy in children of dishwasher owners may be due to less bacterial exposure, or due to toxic exposure (possibly of the dishwasher detergent itself), or some other factor. Despite the lack of definite conclusion as to what the study might show us it is worth bearing in mind that moving too far from the environment our genes adapted to over millennia could carry its own costs.
By Tom Sokolowski