Early Nutritional Strategies to Prevent Allergy
One of the determinants of allergy development would be genetics. Having even just one parent with an allergy already gives their child a 20-40% risk of developing allergies. Despite certain groups being more vulnerable, with the rise of the prevalence of allergies worldwide and majority of cases being from those without the genetic predisposition, it is still worthwhile for even low-risk populations to subscribe to nutritional strategies to prevent allergy development.
Breastfeeding remains the gold standard for infant feeding, and a healthy and balanced diet is recommended for the mother for optimum infant nutrition from pregnancy through to lactation. But in cases where exclusive breastfeeding is not possible, certain infant formulas could contribute to lessening risks for eczema and asthma as per the German Infant Nutritional Intervention (GINI) study.
• We should apply allergy prevention strategies to everyone as the low-risk group will contribute towards the majority of new incidence of allergies.
• Not all formulas are created equal for allergy prevention, and one should choose the formula backed by medical evidence.
• Guidelines recommend no dietary restriction for the mother during pregnancy and breastfeeding in preventing allergies.
Having a family history of allergy raises a child’s risk of developing an allergy later in life. In general, having one parent with an allergy puts a child at 20-40% risk of developing an allergy; this risk roughly doubles if both parents have allergies. Among infants born to parents with no allergies, there is a 15% probability that an allergy will develop. However, in absolute numbers, it is this “no family history of allergy” group that will account for majority of cases of allergies. Thus, we should look at prevention strategies for everyone and not be limited to a selected high-risk group.
The GINI Study
The German Infant Nutritional Intervention (GINI) study is an ongoing birth cohort study, started in 1994, to evaluate the long-term effects of hydrolyzed formulae on allergic diseases in high-risk children. This trial demonstrated that the use of partially hydrolyzed whey (pHF-W) or extensively hydrolyzed casein (eHF-C) in nonexclusively breastfed infants at risk of allergy, led to a lower incidence of eczema for the first 4 months of life compared with cow’s milk formula. The preventive effect persisted until the children were 11-15 years old.
Recent data from the 20-year followup of the GINI study 1 showed that feeding with eHF-C and pHF-W formula during the first 4 months of life reduced the risk of eczema and asthma up to young adulthood. In the intention-to-treat analysis, asthma prevalence between 16 and 20 years was significantly lower in the eHF-C group and in the pHF-W group compared to standard cow’s milk formula (CMF). The risk-reducing effects of eHF-C and pHF-W on eczema was also strongly demonstrated in the per-protocol analysis, consistent with the results reported during the 15-year follow-up of the GINI study.
The GINI study reinforces the concept of the allergic march, in which eczema can predispose to allergic rhinitis and asthma later in life, and interventions that reduce eczema can reduce later atopic manifestations.
Reducing allergic response: Not all hydrolyzed formulas are created equal
The GINI study demonstrated that not all hydrolyzed formula can prevent allergy. Heat techniques used in the manufacture of infant formula can alter the conformation of heat-labile proteins, resulting in the loss of conformational epitopes that elicit allergic response. Allergenicity of linear epitopes can also be altered by enzymatic hydrolysis. An analysis of electrophoretic patterns of proteins from 12 hydrolyzed milk formulas demonstrated formula difference due to different manufacturing processes.2 A latest meta-analysis, undertaken using a single manufacturer pHF-W formula, demonstrated that only a particular pHF-W can offer allergy prevention.3 Thus, it is important to use a proven hydrolyzed formula that has evidence of allergy prevention.
Role of Breastfeeding
Current guidelines recommend human milk as the “gold standard” for infant nutrition. The latest EAACI guidelines4 has no specific recommendations for or against breastfeeding for allergy prevention. Mothers should not restrict consumption of specific allergenic foods and should eat a healthy, balanced diet when pregnant and breastfeeding. This applies regardless of the infant’s risk of food allergy. The taskforce specifically advised against using regular cow milk formula supplementation in breastfed infants during the first week of life as it may lead to increased incidence of cow milk allergy. 5 Other temporary supplementary options may be used, such as donor breast milk, hydrolyzed formula, and amino acid formula.