Food Introductions and Children’s Allergies
By Jaclyn Chasse, ND
If your practice includes any children, you have probably heard parents’ questions about when and how to introduce food to their infant and how their decision impacts the child’s potential for food allergies. Their concern is not unfounded. Over the last decade, the incidence of food allergy in children has increased from 1% to 10% worldwide.1 In the US, the prevalence of food allergy is reported to have increased by 18% between 1993 and 2006.2 With the rise in allergies and atopic illness (eczema, allergies and asthma) in children, parents naturally want to do whatever they can to lessen the risk that these conditions will affect their children.
Over the last decade, recommendations have shifted away from delayed food introduction based upon newly published research. In the past, most pediatric groups and experts, across integrative and conventional medicine, recommended delaying foods such as cow’s milk until age 1, eggs until 2 years, and peanuts and seafood until age 3. It was believed that early exposure to potentially allergenic foods in the intestines could cause sensitization for the child and leave them at an increased risk of allergy.3 At the time, it was believed, more theoretically, that because the infant’s gut mucosal barrier was immature, that the early introduction of foods could trigger sensitivities. Interestingly, a similar theory was applied to topical allergens as well as inhaled allergens, although outside the scope of this article. 2012 World Health Organization recommendations proposed exclusive breastfeeding for the first six months in order to prevent allergic diseases in children.4
This perspective has begun to shift, and now the leading thoughts are that early exposure may actually improve tolerance to the proteins through regulatory T-cell pathways.5 Part of this concern arose because although the above recommendations were enacted (delayed food introduction), there was still an increase in incidence of food allergy and allergic disease in children. (Note: There can obviously be several other factors which come into play in this observed trend, including quality of food, co-administration of gut-harming pesticides in foods, the role of intestinal flora in immune tolerance and early exposures to compounds which can harm this flora balance, among many others.) That being said, the emerging evidence seems to suggest that earlier exposure can be beneficial, as it stimulates early immune tolerance mechanisms in the mucosal surface of the infant’s gut.
Research from Scandinavian countries show that early consumption of fish was associated with lower incidence of allergies in children. In studies in Norway and Sweden, lower levels of eczema and asthma were reported in both high-risk and low-risk children given fish before 9 months of age compared to children where introduction was delayed beyond 1 year. It was also observed in these studies that the greater the dose and the earlier that fish was introduced into the diet, the greater the protection observed.6,7 This could be related to early exposure to fish protein allergens and could also be related to positive impacts of exposure to polyunsaturated fatty acids in fish early on. Further research would be required to discern between the nutritional benefit and the immunological tolerance benefit.
Peanut allergies can be a particularly scary allergen, as the reaction is often anaphylactic and can be triggered even by airborne exposure. An interesting study published in the Journal of Allergy and Clinical Immunology shared the report that Jewish children in the UK had a 10-fold higher prevalence of peanut allergy than Jewish children raised in Israel. There were no differences in the cohorts in regards to genetics, social class, atopy or the peanut allergenicity—the differences were attributed to the fact that children in Israel are exposed to peanuts from an early age, whereas in the UK, typical delayed introduction was applied.8
These reactions may be dependent on the type of food. A new review published in Acta Paediatrica this February by Mermiri et al summarized data that showed that early exposure (after 3 months) to allergenic foods in previously breastfed infants (compared to infants exclusively breastfed through 6 months) had a lower overall incidence of food allergies with eggs and peanuts, but not with cow’s milk, white fish, sesame seeds and wheat.9 Additionally, the same review commented that data shows that diversity of complementary foods in the first year of life can reduce the risk of atopic dermatitis while less food diversity during the first year of life might be linked to a higher risk of developing asthma and allergies in childhood.
The Why Behind Early Exposure and Immune Tolerance
Unfortunately, we don’t have good human studies to support a full understanding of the immune process surrounding early exposure to foods and immune tolerance. Much of the data to date is coming out of in vitro studies, with further studies pending. There seem to be several factors at play, however. First, many of the foods which were commonly avoided in early childhood (fish, eggs, etc.) contain nutrients which have anti-inflammatory qualities (including EPA and DHA fatty acids, phosphatidyl choline, glutathione precursors and more) which could assist with immune balancing from a nutritional perspective. There are likely additional antigen-driven responses. It is believed that early exposure to allergenic foods may trigger an immune response much like immunotherapy (at least with some foods).
In addition to early exposure to allergenic foods, other factors have been evaluated regarding their influence on childhood atopic disease. One randomized controlled trial showed that mothers who consumed polyunsaturated fatty acids during pregnancy and lactation had offspring with a lower incidence of food allergies, allergies and immunoglobulin E (IgE) associated eczema in the first year of life.10 Another review published in 2011 showed that mother’s antioxidant status during pregnancy and their children’s consumption of antioxidants protected against the development of allergies and atopic illness.11
The American Academy of Allergy, Asthma, and Immunology has recommended that mothers not be on any avoidance diets during pregnancy and lactation (assuming no child reactions to foods through breastmilk) and has recommended that infants be breastfeed for a minimum of four months, with food introduction beginning between 4 and 6 months of age. Other agencies across Europe have issued guidance which is substantially similar. While this guidance may be in conflict with guidance shared when we learned food introduction techniques in school, the current scientific evidence seems to support this recommendation.
Breastfeeding should be prioritized for infants whenever possible and research shows that adding antioxidants and fatty acids to children’s diets at the time of food introduction is beneficial, through diverse diets. While every child-mother pair must be considered individually, we hope that this guidance allows you to update your general thinking on food allergy and atopic disease in children.
- Lack G. Clinical practice. Food allergy. N Engl J Med. 2008 Sep 18; 359(12):1252-60.
- Branum AM, Lukacs SL. Food allergy among children in the United States. Pediatrics. 2009 Dec; 124(6):1549-55.
- American Academy of Pediatrics. Committee on Nutrition. Hypoallergenic infant formulas. Pediatrics. 2000 Aug; 106(2 Pt 1):346-9.
- The Optimal Duration of Exclusive Breastfeeding: Report of an Expert on Consultation. Geneva: World Health Organization; March 28-30, 2001.
- Lack G. Epidemiologic risks for food allergy. J Allergy Clin Immunol. 2008 Jun; 121(6):1331-6.
- Alm B, Aberg N et al. Early introduction of fish decreases the risk of eczema in infants. Arch Dis Child 2009;98:823-27.
- Oien T, Storro O et al. Do early intake of fish and fish oil protect against eczema in doctor-diagnosed asthma at 2 years of age? A cohort study. J Epidemiol Community Health 2010;64:124-9.
- DuToit G, Katz, et al. Early consumption of peanuts in infancy is associated with a low prevalence of peanut allergy. J Allergy Clin Immunology 2008;122:984-91.
- Mermiri DT, Lappa T, Papadopoulou AL. Review suggests that the immunoregulatory and anti-inflammatory properties of allergenic foods can provoke oral tolerance if introduced early to infants’ diets. Acta Paediatr 2017 Feb 7. Doi: 10.1111/apa.13778. (Epub ahead of print).
- Furuhjelm C. Warstedt K. et al. Fish oil supplementation in pregnancy and lactation may decrease the risk of infant allergy. Acta Paediatrica 2009;98:1461-7.
- Patelarou E, Giourgouli G, et al. Association between biomarker-quantified antioxidant status during pregnancy and infancy and allergic disease during early childhood: a systemic review. Nutr Rev 2011;69:627-41.
Dr. Jaclyn Chasse is a naturopathic physician and the VP of Scientific and Regulatory Affairs for Emerson Ecologics. She proudly serves as the President of the AANP and thinks everyone needs a good probiotic!