Preterm Infants on Early Solid Foods

Aim: In a prospective, randomized, two arm intervention study- the PIES project- we aim to investigate the impact of different time points of introduction of complementary food on growth, body composition, atopic disease and neurodevelopmental outcome in preterm infant with a birth weight <1500 grams. Furthermore, we want to investigate whether a certain standardized feeding protocol meets the nutritional needs of premature infants, and obtain data on safety and efficacy in this context. Methods: At term infants are stratified according to breastfed or formula fed and randomized in one of the following groups: an EARLY complementary feeding group (introduction of complementary food between the 10th and 12th week of life corrected for term, n=76) and LATE complementary feeding group (introduction of complementary food between the 16th and 18th week of life corrected for term, n=76). The infants will be fed with standardized complementary food in addition to formula or breastfeeding until they are one year corrected for prematurity. In an age dependent step up concept, food boxes are delivered to the parents: five types of standardized food boxes with manifold complementary food according to the infants' age and the ability to tolerate small pieces are available for each child during the study. The standardized complementary feeding regimen allows calculating exact intake of nutrients and therefore will provide information concerning primary and secondary outcome. The follow up phase will last until 5 years of age. Within regular visits anthropometric data (height, head circumference, weight, BMI and z-scores ) and body composition via the PeaPod® system will be gathered. Data on atopy will be assessed by clinical scoring system SCORAD (SCORing Atopic Dermatitis) and the laboratory parameters Fx5(Fx5 test uses six food allergens: wheat, egg, cow's milk, soya, peanut and fish) and IgE (immuneglobulineE). Neurodevelopmental outcome will be assessed at the age of one and two years corrected for term by the Bayley Scales and the K-ABC (Kaufman Assessment Battery for Children). The nutritional concept will be monitored concerning short term safety and efficacy (bone metabolism, iron status, protein- and lipid status) as well as regarding long term outcome (diabetes and obesity markers IGF-1 (Insulin-like growth factor-1, adiponectin and leptin).

With the PIES project we intend to close a gap of knowledge in feeding the premature infant during the first year of life and to understand the impact of complementary feeding on growth, atopy, neurodevelopmental outcome and later obesity.

• Early intervention group (Other), also known as commercially available solid food: solid food will be introduced between week 10 and 12
• Late intervention group (Other), also known as commercially available solid food: solid food is introduced between 16-18th week of gestation corrected for prematurity

Primary outcomes

• Height: [1 Year]: To investigate whether a height difference of 5% at one year of age, corrected for prematurity, can be achieved between the early and the late intervention group. Height will be measured under standardized conditions in centimeter (cm) at defined times during the first year of life until one year of age corrected for prematurity. Measurements will be done before, within and after intervention in order to demonstrate the changes due to all intervention tools.

Secondary outcomes

• neurodevelopmental outcome [5 years]: To achieve an improvement of neurodevelopmental outcome assessed by Bayley scales and the K-ABC
• IGF-1 [5 years]: To evaluate the risk for later obesity
• FX5 [5 years]: To achieve a reduction in risk for atopic diseases
• SCORAD [5 years]: To achieve a reduction in risk for atopic diseases.
• Body composition [5 years]: To achieve an increase of free fat mass (FFM) in body composition measured with the Peapod.
• Vitamin D [1 year]: To achieve a degree of bone mineralization.
• Iron status [1 year]: To achieve the development of anemia
• Leptin [5 years]: To evaluate the risk for later obesity
• BMI [5 years]: to evaluate anthropometric parameters
• weight [5 years]: to evaluate anthropometric parameters
• head circumference [5 years]: to evaluate anthropometric parameters
• z-scores [5 years]: to evaluate anthropometric parameters

Sex: All, ages: 1 Week to 3 Months

Inclusion Criteria:

* Preterm infants <1500 gram
* Informed consent

Exclusion Criteria:

Diseases affecting stable growth:

* Gastrointestinal diseases: necrotizing enterocolitis, Hirschsprung disease, chronic inflammatory bowel disease
* Bronchopulmonary dysplasia (BPD) defined as oxygen demand above 36 week gestational age
* Congenital heart diseases
* major congenital birth defects
* chromosomal aberrations

• Results publication: Gsoellpointner M, Thanhaeuser M, Kornsteiner-Krenn M, Eibensteiner F, Ristl R, Jilma B, Brandstetter S, Berger A, Haiden N. Nutritional intake and growth in very low birth weight infants: a comparison of standardized versus parent-led complementary feeding. Eur J Clin Nutr. 2026 Aug 8. doi: 10.1038/s41430-026-01809-z. Online ahead of print. PMID 42570946
• Results publication: Gsoellpointner M, Eibensteiner F, Thanhaeuser M, Ristl R, Jilma B, Berger A, Haiden N. Effects of early introduction of solid foods on nutrient intake in preterm infants during their 1st year of life: a secondary outcome analysis of a prospective, randomized intervention study. Front Nutr. 2023 May 18;10:1124544. doi: 10.3389/fnut.2023.1124544. eCollection 2023. PMID 37275631

• Nadja Haiden, Principal investigator, Medical University of Vienna