Six randomised controlled trial (RCTs, including three head-to-head studies with 147 children and three open or double-blinded food challenge RCTs with 66 children), seven before-and-after clinical trials (n=195 children) and seven cohorts or case reports (n=8 children) were included. Three RCTs scored 5 points out of 5 on the Jadad scale; others scored 4, 3 or 2 points. Three RCTs were judged to be poorly described or planned.
Amino acid-based formula versus extensively hydrolysed formula (six RCTs, five before-and-after clinical trials, five cohorts or case reports): Three head-to-head comparison RCTs found no significant differences between amino acid-based formula and extensively hydrolysed formula in improvements in gastrointestinal or dermatological symptoms. Two RCTs reported significant differences in one or two measures of growth favouring amino acid-based formula. One RCT reported no difference in two of three growth measures. Three cross-over challenge RCTs found that there were no significant differences in the number of children developing gastrointestinal, respiratory or behavioural problems between amino acid-based formula and extensively hydrolysed formula.
Amino acid-based formula versus soy-based formula (two cross-over RCT challenge trials, two before-and-after clinical trials, two cohorts or case reports): One cross-over challenge RCT reported adverse effects following challenge with soy in children asymptomatic on amino acid-based formula. The other cross-over challenge RCT reported no adverse effects of amino acid-based formula in children tolerant to soy.
Amino acid-based formula versus cow’s milk or milk-based formula (two cross-over RCT challenge trials, two before-and-after clinical trials, two cohorts or case reports): The two cross-over challenge RCTs reported tolerance of amino acid-based formula.
Other results, plus results for before-and-after clinical trials and cohorts or case reports, were also reported.