Why does food allergy appear to be on the increase globally?
Globally, the consensus is that food allergy is on the increase. Do we have enough evidence to support this?
Some scientists and doctors agree that this is true while some say it is not the case. For the school of thought that says it is not true, it is believed that over-diagnosis of food allergy is the case here. This might be a result of the increase in allergy panel kits easily available which people including patients can use for their children. This is widely frowned upon by allergy doctors as much medical history is required as well as expert interpretation to use such kits.
Why is this so?
There are various hypotheses that have been made to support the reason why food allergy is on the increase. They include:
Changes to the environment because of modern lifestyle.
Increased prevalence of eczema. This is also known as the dual allergen exposure hypothesis.
Various lifestyle changes are attributed to modernisation which may impact the prevalence of food allergies. Some researchers in this field suggest that the western lifestyle has resulted in the disappearance of ‘dirt’. With less exposure to the natural environment, there is less opportunity for babies to interact with diverse microbes, vegetation, soil, etc. In addition, an increased number of C-sections has also been suggested may contribute to the increase in allergy globally. This is known as the “old friends’ hypothesis” where the new born is not introduced to ‘friendly’ microbiota at birth.
Still, on lifestyle changes, the influence of modern diet has also been highlighted to be a major contributor to this hypothesis. Migration is also highlighted to play a role in the impact of lifestyle changes.
Increased prevalence of eczema
The prevalent use of strong detergents and antiseptics has been suggested to disturb the ‘good’ microbiota as well as disrupt epithelial barriers. Most of the discussions around eczema suggest that the skin and the gut microbiome are disrupted which results in an increase in food allergy. In a recent review, it was concluded that the use of moisturisers in the first year of life does not prevent eczema. However, this may increase the risk of skin infection whilst the effect on food allergy was unclear.
The influence of diet and reduced microbiome diversity forms the bedrock of scientific thinking on the allergy epidemic. Based on these hypotheses, it is believed that preventative strategies could be explored to restore the previous symbiotic relationship that previously existed. Whilst research is going on to explore these opportunities, let’s look at the protective and risk factors for allergy development in early life. They include:
Mode of delivery of a baby
Maternal use of antibiotics
Use of infant formula
Antibiotic use in infants
Close contact with pets and farm animals
Immune system development
These factors will be explored further. Keep an eye out for it! Updates will be shared through our social media platforms.
The references explored for this blog which you can check out for further information include:
Kellerher MM et al. (2021) Cochrane Database of systematic Reviews. Issue 2
Ma et al. ( 2021) Pediatr Allergy Immunol. 32:1073
Lambrecht & Hammad (2017) Nature Immunology 18 (10): 1076
Sicherer et al (2010) J Allergy Clin Immunol. 125: 1322
Venter et al. (2010) Allergy. 5:103