By Amy Norton
The products, known as hydrolysed infant formulae, are designed to lower the likelihood of the allergic responses some infants have to standard formula.
Like standard formula, hydrolysed products contain cow's milk proteins; the difference is that the proteins are broken down so that they are less allergenic than the whole proteins in regular formula.
Studies have shown that compared with regular formula, hydrolysed versions seem to lower the risk of allergies in infancy and early childhood. The new findings suggest that those benefits last at least until the age of six.
German researchers found that among more than 2 200 newborns at genetic risk of developing allergies, those given hydrolysed formula were less likely to develop the allergic skin condition eczema by age six.
Compared with their peers who received standard formula, those given a hydrolysed version were up to 29 percent less likely to develop eczema, depending on the type of hydrolysed formula.
Breast milk is considered the best nutrition for infants, and has been shown to lower the risk of allergies.
But in cases where an infant has a parent or sibling who has suffered allergies, and it is necessary to supplement breast milk, parents should use a hydrolysed formula, said Dr. Andrea von Berg, the lead researcher on the new study.
Von Berg, of Marien-Hospital Wesel, and colleagues report the findings in the Journal of Allergy & Clinical Immunology.
The study included 2 252 children born between 1995 and 1998 who all had at least one parent with allergies. All mothers in the study were encouraged to breastfeed, but in cases where breast milk was insufficient, they were randomly assigned to supplement with one of four options: standard formula, partially hydrolysed whey formula, "extensively" hydrolysed whey formula or extensively hydrolysed casein formula.
Overall, the researchers found, children on any of the hydrolysed formulae were less likely to develop allergies by the time they were six years old. A lower eczema risk appeared to be largely responsible for the difference.
In general, children in the hydrolysed formulae groups were up to 29 percent less likely to develop eczema, and the protective effect was more pronounced when the researchers looked only at children whose parents had fully complied with the study's feeding regimen.
One of the formulae - the extensively hydrolysed whey formula - only showed benefits when the children were six years old, von Berg told Reuters Health. In contrast, the other two had protective effects from the first year onward.
"So my preference," the researcher noted, "is one of (those) two."
However, von Berg said, infants who show an allergic reaction to regular formula should not be given a formula that is only partially hydrolysed. In these cases, parents should always consult their paediatrician.