Infant health research

The research below explores the effects of breastfeeding, formula feeding and the early introduction of certain foods on the prevalence of allergies in babies and young children.

Frequency of guideline-defined cow’s milk allergy symptoms in infants: Secondary analysis of EAT trial data

Conclusions from a secondary analysis of the Enquiring About Tolerance (EAT) randomised controlled trial indicate that guideline defined symptoms of non-IgE cow’s milk allergy are very common in infants, thereby having the potential to promote milk allergy over-diagnosis by labelling normal infant symptoms as possible milk allergy.

Vincent, R. et al. 2021. Frequency of guideline-defined cow’s milk allergy symptoms in infants: Secondary analysis of EAT trial data. DOI: 10.1111/cea.14060

Allergy societies and the formula industry

From the early years, the formula industry aligned itself with allergists and other trusted sources of infant feeding information, leading to widespread inappropriate guidance for infant feeding and false promotion of special health-promoting properties of formula. Hydrolysed formula has been inappropriately recommended for allergy prevention for over 30 years and there is excessive consumption of specialised formula in some regions due to milk allergy overdiagnosis. Formal analysis of allergy societies’ relationships with formula companies has not yet been undertaken, but it is likely that most societies and many conferences and educational activities are sponsored by formula companies. This article discusses the World Allergy Organization’s alignment with the formula industry and calls on them to follow WHO guidance, protect the patients that their members serve and stop accepting funding from formula companies.

Boyle, RJShamji, MHAllergy societies and the formula industryClin Exp Allergy2021511260– 1261.

Breastfeeding and the developmental origins of mucosal immunity: how human milk shapes the innate and adaptive mucosal immune systems

This review summarises current knowledge and new discoveries about human milk and mucosal immunity, including how certain microbes in maternal milk seed and shape the infant gut microbiota which helps to regulate gut barrier integrity and training of the developing immune system. Human milk oligosaccharides have been shown to directly modulate gene expression in mast and goblet cells in the gastrointestinal tract, with data showing a reduced risk of peanut sensitisation among infants breastfed by peanut-consuming mothers, thereby suggesting a role for milk-borne food antigens in tolerance development. Finally, interest in human milk antibodies surged during the pandemic with the identification of neutralizing severe acute respiratory syndrome coronavirus 2 antibodies in maternal milk following both natural infection and vaccination. In summary, human milk provides critical immune protection and stimulation to breastfed infants.

Dawod, Bassela,b; Marshall, Jean S.a,b; Azad, Meghan B.c,d,e Breastfeeding and the developmental origins of mucosal immunity: how human milk shapes the innate and adaptive mucosal immune systems, Current Opinion in Gastroenterology: November 2021 – Volume 37 – Issue 6 – p 547-556 doi: 10.1097/MOG.0000000000000778

Hydrolysed formula and allergy prevention

Over the past 30 years, hydrolysed formula has been recommended to prevent allergy in infants – an endorsement supported by historically fraudulent research and selectively reported trials. New TRIGR trial results are discussed in this editorial which reinforce the evidence that whilst extensively hydrolysed formula has a role in managing children with certain intestinal conditions or milk allergy, there is little evidence that hydrolysed formula aids in feeding healthy infants or helps to reduce allergy risk.

Genuneit, J., Boyle, R. Hydrolysed formula and allergy prevention. February 2021. Wiley. DOI: 10.1111/pai.13470

Assessment of Evidence About Common Infant Symptoms and Cow’s Milk Allergy

This study aims to understand whether cows’ milk allergy (CMA) guideline recommendations might promote CMA over-diagnosis or undermine breastfeeding, particularly in light of recent increases in sales of specialized formula for managing CMA. Authors reviewed recommendations made in CMA guidelines and critically appraised 2 key recommendations. In their key conclusions, the authors found that recommendations to manage common infant symptoms as CMA are not evidence-based, especially in breastfed infants who are not directly consuming cow’s milk. Such recommendations may cause harm by undermining confidence in breastfeeding.

Munblit D, Perkin MR, Palmer DJ, Allen KJ, Boyle RJ. Assessment of Evidence About Common Infant Symptoms and Cow’s Milk Allergy. JAMA Pediatr. 2020;174(6):599–608. doi:10.1001/jamapediatrics.2020.0153

Effect of an Intervention to Promote Breastfeeding on Asthma, Lung Function, and Atopic Eczema at Age 16 Years

In this adolescent follow-up of a cluster randomized trial in Belarus, which assessed the effect of a breastfeeding promotion intervention vs usual care among 13,557 participants, there was a 54% reduction in atopic eczema on skin examination but no significant effect on lung function (spirometry) and self-reported asthma diagnosis and symptoms of atopic eczema and wheezing in the past year.

Carsten, F, et al (2018), Effect of an Intervention to Promote Breastfeeding on Asthma, Lung Function, and Atopic Eczema at Age 16 Years, doi:10.1001/jamapediatrics.2017.4064

Assessing the health benefits and risks of the introduction of peanut and hen’s egg into the infant diet before six months of age in the UK

This review of evidence from the Scientific Advisory Committee on Nutrition (SACN) and the Committee on Toxicity (COT) explored whether peanut and hen’s egg should be introduced to an infant’s diet before six months in order to reduce the risk of developing food allergies. They concluded that there was not enough evidence to support this early introduction, reinforcing current recommendations to exclusively breastfeed for 6 months and to only introduce solids around 6 months of age. They also noted that the deliberate exclusion of peanut or hen’s egg beyond six to twelve months of age may increase the risk of allergy to the same foods. Once introduced, and where tolerated, these foods should be part of the infant’s usual diet, to suit both the individual child and family.

SACN/COT Working Group (2017), Assessing the health benefits and risks of the introduction of peanut and hen’s egg into the infant diet before six months of age in the UK.

Hydrolysed formula and allergies

This study sought to determine whether feeding infants with hydrolysed formula reduces their risk of allergic or autoimmune disease. The findings do not support current guidelines that recommend the use of hydrolysed formula to prevent allergic or autoimmune disease in high risk infants.

Boyle, R (2016), Hydrolysed formula and risk of allergic or autoimmune disease: systematic review and meta-analysis. BMJ DOI:

Breastfeeding and asthma and allergies

This study systematically reviewed the association between breastfeeding and childhood allergic disease. The authors found some evidence that breastfeeding is protective for asthma (5–18 years). There is weaker evidence for a protective effect for eczema ≤2 years and allergic rhinitis ≤5 years of age, with greater protection for asthma and eczema in low-income countries.

Lodge, C.J. et al (2015) Breastfeeding and asthma and allergies: a systematic review and meta-analysis. Acta Paediatrica, Special Issue: Impact of Breastfeeding on Maternal and Child Health. Volume 104, Issue Supplement S467, pages 38-53. 

Infant nutrition and atopic disease

This American review found evidence that breastfeeding for at least 4 months, compared with feeding formula made with intact cow milk protein, prevents or delays the occurrence of atopic dermatitis, cow milk allergy, and wheezing in early childhood.

Greer et al. (2008) Effects of early nutritional interventions on the development of atopic disease in infants and children. PEDIATRICS; 121 (1): 183-191

Breastfeeding duration and atopic dermatitis and asthma

This German study found that a longer breastfeeding duration reduces the risk of allergies in early childhood, and linked this protective effect to the concentration of soluble CD14 in breastmilk.

Rothenbacher D et al (2005). Breastfeeding, soluble CD14 concentration in breast milk and risk of atopic dermatitis and asthma in early childhood: birth cohort study. Clin Exp Allergy 35: 1014-21.

Breastfeeding reduces the risk of five types of allergic disease

This study of 4,089 infants in Sweden found that breastfeeding had a preventive effect on the early development of five allergic diseases: asthma, suspected allergic rhinitis, atopic dermatitis, food allergy related symptoms, and suspected allergic respiratory symptoms after exposure to pets or pollen.

Kull I et al (2002). Breast feeding and allergic diseases in infants–a prospective birth cohort study. Arch Dis Child 87: 478-481.

Exclusive breastfeeding and allergies

An investigation among 2,195 children followed up to age 6 years concludes that less exclusive breastfeeding leads to increases in child asthma and atopy.

WH Oddy, JL Sherriff, NH de Klerk, GE Kendall, PD Sly, LJ Beilin, KB Blake, LI Landau, and FJ Stanley. The relation of breastfeeding and body mass index to asthma and atopy in children: a prospective cohort study to age 6 years. Am J Public Health, 2004; 94: 1531-7

Breastfeeding and allergy protection

This review of 132 studies concluded that breastfeeding seems to protect from the development of atopic disease. The effect appears even stronger in children with atopic heredity.

J van Odijk et al (2003). Breastfeeding and allergic disease: a multidisciplinary review of the literature (1966-2001) on the mode of early feeding in infancy and its impact on later atopic manifestations. Allergy 58(9): 833-43.

Related research and further reading

Emerging research: Epigenetics and the microbiome

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The impact of breastfeeding on maternal and child health: Acta Paediatrica special issue

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The Lancet: Increasing breastfeeding worldwide could prevent over 800,000 child deaths every year

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