Food allergies are immediate reactions which can be brought on by a small amount of the trigger substance. There are a wide range of responses you can have ranging from rashes, runny nose and watering eyes to swelling of the airways requiring immediate medical attention. In the United Kingdom more than 50% of children suffer from some form of allergy, however they can present at any point in life(1). The reason why allergies develop is not well understood, but it is an area of concern for health care professionals since they are becoming more and more common(2).
The role the gut plays in allergy risk is not immediately obvious however, our gastrointestinal tract houses 70% of the body’s immune cells(3). Therefore, our gut microbiome is able to interact with the immune system and our immune response. Hypersensitivity of this immune system is what presents as an allergy. When gut health is poor the lack of friendly flora means harmful bacteria can populate the gut. This may result in changes to the gut lining making it more permeable. As a result, undigested food particles can end up entering the bloodstream and triggering an inflammatory response with allergy symptoms.
Figure 1. Demonstrates how an overgrowth of harmful bacteria can damage the lining of the gut resulting in food particles entering the bloodstream where immune cells lie.
The impact the gut microbiome has on the immune system can be demonstrated through research observing differences in allergy development risk between children born through Caesarean section or vaginal birth. Research suggests that delivery method may influence allergy risk in later life, with babies born via Caesarean section having increased susceptibility1. This is believed to be due to the baby only receiving beneficial maternal bacteria through a natural vaginal birth. As a result, this can influence the development of the baby’s gut microbiota and subsequently their immune response.
Furthermore, a 2013 study found an association between parents that cleaned their baby’s dummy by sucking it, and decreased allergy development. This research involved 184 babies who were tested for allergy development over the first three years of their lives. The babies who had their dummies cleaned through sucking had a 49% reduced risk of developing eczema at the end of three years. Further analysis of 33 of these infants saw increased gut bacterial diversity in those who had their dummies sucked4. This was believed to be due to the bacteria the parent passes on to the child through sucking their dummy, impacting the development of the baby’s microbiome.
Can live culture supplementation decrease allergy severity and risk?
Research has shown benefit in giving children with allergies friendly bacterial supplements this is believed to help the child’s gut flora to flourish. One case saw infants with cow’s milk allergy having an improved tolerance to cow’s milk when it was given alongside with friendly bacteria5. This study indicates the benefit of live cultures in supporting the body against allergens and demonstrates the need for a balanced gut microbiome for overall health.
1. Henry Ford Health System. Babies born by C-section at risk of developing allergies. ScienceDaily. ScienceDaily, 25 February 2013.
2. Pawankar R, Canonica GW, ST Holgate. The WAO White Book on Allergy 2013
3. Montalban-Arques A et al. Selective Manipulation of the Gut Microbiota Improves Immune Status in Vertebrates, Frontiers in Immunology. 2013. 9;6:512.
4. Hesselmar et al. Pacifier cleaning practices and risk of allergy development', Pediatrics.2013
5. Canani and Costanzo, Gut Microbiota as Potential Therapeutic Target for the Treatment of Cow’s Milk Allergy, Nutrients. 2013; 5(3): 651–662.