You are not alone if your child or infant has been diagnosed with a food allergy. In Australia, 10% of infants and 4-8% of children are diagnosed with a food allergy. The most common foods linked to food allergies are soy, shellfish, nuts, peanuts, tree nuts, sesame, eggs, wheat, fish, and milk.
The cause of food allergies is not a simple one as there are many factors which may influence an infant or child’s risk of developing an allergy. Factors such as genetics, if the child was born vaginally or via caesarean, use of antibiotics, and the diet of the mother during pregnancy and of the child once solid foods are introduced. The type of microbes which make up a child’s gut microbiome may also play an important role in preventing and treating allergies.
Your gut microbiome is determined by the number and variety of different types of microbes. Some species are health promoting types and some promote ill health consequences in your body. There is a fine balance to what makes a healthy gut microbiome. Some health promoting microbes can become ill health promoting if the number becomes imbalanced. Everyone has a different gut microbiome, and it is as unique to your as your fingerprint.
The type of microbes present in your gut is largely determined by your diet. When the microbes eat, they excrete short chain fatty acids such as butyrate, which influence the function and health of your body. Microbes can also ill health promoting signals depending on the source of fuel eaten. A diet high in saturated fats, animal-based foods like red meat, high in added sugar and low in plant-based foods promotes disease promoting microbes and an imbalance of gut microbes in your gut.
Studies suggest that consuming a diet which is high in dietary fibre may promote a healthy gut lining and support your immune system to function optimally. Health promoting microbes use fuel from prebiotic fibre, a type of undigestible fibre as well as polyphenols found in plant foods. An important factor promoting an optimal balance of health promoting microbes is through the inclusion of a variety of plant-based foods in your diet. This includes wholegrains such as CornThins, nuts, seeds, legumes, vegetables, and fruit. Aiming for 30 different plant foods each week provides a variety of different prebiotic fuel sources for the diverse range of health promoting gut microbes.
Beyond plant based foods, omega-3 fat is seen to have a positive effect on the gut microbiome. Omega-3 fat is an essential polyunsaturated fat found in foods such as walnuts, chia seeds, linseeds, soybean as well as seafood. Seafood is an especially good source of the type of omega-3 fat which your body can use easily. Good sources are fatty fish like salmon, herring, mackerel, and sardines. Omega-3 fat, unlike saturated fat, has an anti-inflammatory effect on your body.
Around seventy percent of your immune system is found in your gut. This fact alone gives insight to the potential role of your gut microbiome in allergies. Research is still developing but insights have been seen in research such as children with cow’s milk allergy which was present at infancy but resolved by eight years of age have a gut microbiome with higher levels of Clostridia and Firmicutes.
Another study investigated the different types of gut microbes present in ninety children with food or respiratory allergies compared to thirty children of the same age without allergies. Children were studies for 36 months duration with assessment of food allergies tested at each 12 month interval. Researchers found that children with allergies had different types and number of microbes. Specifically, higher levels of Faecalibacterium prausnitzii, Ruminococcus gnavus and lower levels of Bifidobacterium longum, Bacteroides vulgatus, Bacteroides dorei, as well as groups of microbes which consumed fibre.
Ruminococcus gnavus have a lower ability to eat fibre and had pro-inflammatory properties. This strain of microbe is predicted to be a major player in promoting allergic reactions in children, although further research is needed to determine this prediction.
Take home message: There are many factors which may influence a child’s risk of developing an allergy. The gut microbiome may be one important component to consider and may be a future strategy to prevent and treat allergies.
References:
- De Filippis, F., Paparo, L., Nocerino, R. et al. Specific gut microbiome signatures and the associated pro-inflamatory functions are linked to pediatric allergy and acquisition of immune tolerance. Nat Commun 12, 5958 (2021). https://doi.org/10.1038/s41467-021-26266-z
- Bunyavanich, S., Shen, N., Grishin, A., Wood, R., Burks, W., Dawson, P., Jones, S. M., Leung, D., Sampson, H., Sicherer, S., & Clemente, J. C. (2016). Early-life gut microbiome composition and milk allergy resolution. The Journal of allergy and clinical immunology, 138(4), 1122–1130. https://doi.org/10.1016/j.jaci.2016.03.041
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