The role of milk feeds and other dietary supplementary interventions in preventing allergic disease in infants: Fact or fiction?

Exclusive breastfeeding ideally up to 6 months of life is the feed of choice for infants and should be promoted by healthcare professionals. However, when human milk is not sufficient or not available, infant formula, generally cow's milk-based, meeting strictly regulated nutritional and safety requirements, are recommended. Human breastmilk feeding has a positive health impact for both mother and child, but there is limited evidence that it has a long-term protective effect on the development of allergic disease. Some studies have found an association of an increased risk to develop cow's milk allergy with early exposure to cow's milk protein in formula milk. As a result, over the last 30 years, partially hydrolyzed formulas (pHF) have gained popularity and, more recently, become embroiled in a debate about their role in the primary prevention of allergic outcomes. Similar debates exist in regards to the potential preventative effects of pre-, pro- and synbiotics as well as nutritional factors, notably vitamin D and omega-3 fatty acids. This paper aims to critically address these aspects, drawing information from published data interpreted by an international expert group in paediatrics, allergy, gastro-intestinal diseases and nutrition. This group of experts emphasize that human milk is the optimal source of infant nutrition. With regards to pHFs, whilst no harm has been shown with their use and some studies have suggested potential benefit preventing atopic dermatitis in at risk infants, there is insufficient evidence for or against their routine recommendation for primary allergy prevention. The method of hydrolysation differs for every formula. There is insufficient evidence to recommend supplementation with vitamin D, omega-3 LCPUFA, specific prebiotic oligosaccharides or specific probiotic strains during pregnancy, lactation and early life to prevent the development of allergic disease in children. There remains a need for well-designed trials with the currently commercialised pHFs and supplements to allow for better clarity and evidence-based recommendations.