Childhood allergies are on the rise worldwide, often starting as simple skin rashes before progressing to food allergies and respiratory conditions such as asthma. Doctors refer to this progression as the “Atopic March“—a pattern in which one allergic condition may increase the likelihood of developing others later in life. Because early nutrition plays an important role in shaping the developing immune system, researchers have long searched for ways to interrupt this process. One approach that has attracted considerable interest is the use of partially hydrolyzed formulas (pHF), which contain cow’s milk proteins broken down into smaller fragments. While some studies have suggested these formulas may help reduce allergy risk, long-term evidence has remained limited, and experts emphasize that results cannot be generalized across all pHF products.
To help address that knowledge gap, a team of researchers tracked children through their preschool years and published their findings in Pediatric Allergy and Immunology. Led by Mikaela Sekkidou from the Asthma and Allergy Center in Cyprus, the team sought to determine whether the benefits of a specific whey-based partially hydrolyzed formula persisted over time. The researchers noted that “evidence on the effectiveness of partially hydrolyzed formulas (pHF) as a nutritional intervention to prevent Allergic Manifestations (AM) is limited.” They also pointed out that because “not all pHF are the same,” it is essential to evaluate individual formulas in long-term studies rather than assuming all products offer the same benefits.
To do this, the scientists conducted a 5-year follow-up study based on a previous project called the Allergy Reduction Trial (ART). The original trial enrolled infants considered at elevated risk for allergic disease because they had a family history of allergies. During the first six months of life, researchers compared three feeding groups: infants who received a specific whey-based partially hydrolyzed formula as part of mixed feeding, infants who received standard cow’s milk formula, and infants who were exclusively breastfed. Years later, the researchers followed up with participating families and collected information on physician-diagnosed allergic conditions that developed between the ages of 1 and 5 years.
The study achieved an impressive 83% follow-up rate, with 455 of the original 551 families participating through the five-year assessment. The final analysis included 131 children who had received the partially hydrolyzed formula, 145 who had received standard formula, and 179 who had been exclusively breastfed. To ensure fair comparisons, the researchers adjusted their analyses for factors that can influence allergy risk, including sex, mode of delivery, and parental history of allergic disease.
The results suggested that children who received the specific whey-based partially hydrolyzed formula experienced significantly lower rates of several allergic conditions than children who received standard formula. By age 5, the overall incidence of allergic manifestations was 32.7% among children who received the partially hydrolyzed formula compared with 51.7% among those who received standard formula. Rates of atopic dermatitis, commonly known as eczema, were also substantially lower, affecting 22.1% of children in the partially hydrolyzed formula group versus 38.5% in the standard formula group.
The most striking findings involved food allergy prevention. Children who received the partially hydrolyzed formula experienced significantly lower rates of food allergy, including benefits that persisted through age 5. The effect was particularly pronounced during the preschool years. Between ages 1 and 5, “infant feeding with the pHF resulted in 87% risk-reduction of FA [food allergy]” compared with standard formula. During that period, only 1.5% of children who received the partially hydrolyzed formula developed a food allergy, compared with 12.4% of children who received standard formula.
Ultimately, the study concluded that for infants at increased risk of allergic disease who cannot be exclusively breastfed, “mixed-feeding with a specific whey-based pHF during the first 6 months of life may reduce the risk of atopic dermatitis and food allergy from birth up to the age of 5 years.” The researchers stressed that breastfeeding remains the preferred feeding option whenever possible and emphasized that these findings apply specifically to the formula tested in the study, not necessarily to all partially hydrolyzed formulas. While the results are encouraging, the authors cautioned that additional research is needed before broad recommendations can be made. They concluded that “further ART follow-ups and other longitudinal studies with larger sample size are needed” to confirm and extend these findings.
