The relationship between our microbes and our allergies is very similar to their relationship to asthma. Our human microbiota continuously shapes our immune system which is the determining factor in whether or not we develop allergies and asthma.
Several factors have been associated with lower prevalence of some allergies, including contact with animals as a child (especially exposure to horse stables under the age of one), breastfeeding, vaginal birth and lack of antibiotics early in life.
The sharp rise of life-threatening food allergies over the past few decades has increased the urgency to find new treatments and/or preventative measures for allergies. Microbes seem to hold the best promise for averting disaster in these serious food sensitivities.