It is thought that :
- Our microbial exposure needs are not confined to a single OF species
- Exposure to a diverse range of species is a requirement
- This may mean that our exposure needs can be met by one or more of a diverse range of microbes which make up the human and environmental microbiome
- If any species is missing, their role may be met by others
What is the route of microbial exposure?
Based on current evidence, the oral and respiratory routes seems the most likely candidate, which fits with the OF mechanism.
However, findings do not rule out other routes including inhalation, which is very effective in animal models, or even transdermal exposure.
Possibly all of these routes are involved.
Does exposure need to be maintained during adult life?
Evidence suggests that the most important time of exposure is during pregnancy, and during the first hours, days or months of life
Evidence suggests that exposure needs to be maintained for a significant period e.g. Breastfeeding for 6 months
There is some evidence that on-going exposure may be important
More research is needed. Most of our understanding comes from studies with infants.
A 2008 Swedish study showed that reduced diversity of faecal microbiota in infants at one week was associated with higher rates of eczema at 18 months
A 2011 Danish study showed that increased risk of allergic disease was associated with less gut microbiota diversity in infancy
A 2007 study showed that, when adults with established Inflammatory bowel disease (IBD) or multiple sclerosis (MS) took part in trials involving oral treatment with helminth (worm) eggs, significant improvement of symptoms was seen.
It has been shown that naturally-occurring helminth infection can delay progression of established early MS