Improved general health status in an unselected infant population following an allergen-reduced dietary intervention programme: the ZUFF-STUDY-PROGRAMME - Part II: infant growth and health status to age 6 months

Aim of the study. An allergen-reduced dietary intervention programme with s trict dietary requirements was implemented over the first four months of li fe in an unselected population-based infant cohort and compared to a non-in tervention cohort (the ZUFF study). Recommendations for the dietary program me in the intervention cohort were extended, but not strictly implemented, until the end of month six. The intervention was based on breastfeeding, a moderate whey hydrolysate formula (pHF), and delayed introduction of weanin g foods with a high allergenicity. This study was a prospective, controlled , and unblinded study, the first to assess the effects of an allergen-reduc ed, pHF based early nutritional programme in a broad unselected infant popu lation. Because overall healthy development of the infant is a major object ive of any nutritional programme, the study evaluated the effects of the di etary intervention on infant growth and general health status rather than s pecific allergic manifestations. Part I of this paper gave results for nutr itional behaviour only, and Part II gives results for growth and general he alth status during the intervention period through the sixth month of life. Methods. Assignment of study infants was to demographically comparable inte rvention (Z) or control (FF) cohorts according to place of birth. In the in tervention cohort (Z=564), the recommended dietary regimen was breastfeedin g and - if exclusive breastfeeding was not possible - supplementation with a moderately hydrolysed, allergen-reduced infant formula (pHF). Weaning foo ds were delayed until four months of age or later in case of weaning foods with high allergenicity. In the control cohort (FF=566), there was no speci fic intervention. Imbalances between cohorts in confounding (adjuvant) fact ors that could influence health-related outcomes were integrated as covaria tes into the logistic regression of the main analyses. Growth parameters in cluded weight, length, head circumference, BMI, and Z scores (SDS). General health status was assessed by clinically significant findings in gastroint estinal, respiratory, or skin symptoms. Results. Growth at 6 weeks and at 3 and 6 months was similar for Z and FF S ignificantly fewer Z than FF infants had clinically noteworthy health findi ngs at 3 months (Z=27% versus FF=37%, odds ratio=0.63, CI=0.48-0.82) and 6 months (Z=33% versus FF=49%, odds ratio=0.51, CI=0.40-0.66). This correspon ds to a 30% reduction in overall health concerns at 6 months for the interv ention cohort. At 3 and 6 months, differences between cohorts in most measu res of general health status were strongly influenced by a lower incidence of skin symptoms in the Z cohort. Within FF, there were fewer exclusively b reastfed (eBF) infants with health problems at 3 months compared with those who were partially (pBF) or non-breastfed (nBF) (eBF=31%, pBF=40%, nBF=39% , p<0.05). In contrast, in the Z intervention cohort, the number of infants with health concerns was similar for exclusively breastfed infants and for those in whom mother's milk was supplemented or replaced by pHF (eBF=29%, pBF=25%, nBF=26%, ns). In a subanalysis of overall health findings in infan ts without a family risk of allergies, there were again significantly fewer Z than FF infants with any health or any skin problem. Conclusion. An allergen-reduced dietary recommendation that includes a mode rate whey hydrolysate infant formula (pHF) has no negative effects on growt h parameters up to 6 months of life in an infant population unselected for atopic risk. The dietary intervention produced improvements in general heal th status when compared with a control cohort that received infant formula with unhydrolysed proteins (IF), and high allergenic weaning foods at an ea rlier age. The difference between cohorts was principally due to fewer adve rse skin findings. In infants following our allergen-reduced feeding recomm endation, 3-month general health status was comparable between those who we re exclusively breastfed and those in whom breastfeeding was supplemented o r replaced by pHF Our results demonstrate that a pHF feeding recommendation during the first 4 to 6 months of life - when exelusive breastfeeding is n ot possible - is a safe and feasible regimen not only in high-allergic risk populations but in a general unselected infant population. The general use of pHF formula in non- or partly breastfed infants could therefore be cons idered an important contribution to optimised infant nutrition.