Early‐life nutrition is associated with processing speed at age 5 in children born preterm with very low birth weight

Objective Processing speed is suboptimal among preterm‐born children which is of concern as it is a foundational skill supporting higher‐level cognitive functions. The study objective was to evaluate associations between early‐life nutrition and processing speed in childhood. Methods Macronutrient and human milk (mother's own, donor) intakes from 137 children born preterm with very low birth weight enrolled in a nutrition feeding trial were included. Processing speed was evaluated at age 5 using the Wechsler Preschool and Primary Scale of Intelligence‐fourth edition Processing Speed Index. Associations between early‐life nutrition and processing speed were explored through linear regression. Results Children had a mean (standard deviation [SD]) birth gestational age of 28.1 (2.5) weeks, weight of 1036 (260) g and 52% were male. The mean (SD) assessment age was 5.7 (0.2) years. Sex‐dependent relationships were identified between first postnatal month protein, lipid and energy intakes and processing speed at 5 years. For females, lower protein (per 0.1 g/kg/d: −0.88, 95% confidence interval [CI]: −1.53, −0.23; p = 0.01) and energy (per 10 kcal/kg/d: −2.38, 95% CI: −4.70, −0.05; p = 0.03) intakes were related to higher processing speed scores. Mother's milk provision was positively associated (per 10% increase: 0.80, 95% CI: 0.22, 1.37; p = 0.01) and donor milk was negatively associated (per 10% increase: −1.15, 95% CI: −2.22, −0.08; p = 0.04) with processing speed scores; no sex differences were observed. Conclusions First postnatal month nutrition was related to processing speed at age 5 in children born preterm with very low birth weight. Early‐life nutrition that supports processing speed may be leveraged to improve later cognitive outcomes for this vulnerable population. What is Known Preterm‐born children exhibit suboptimal processing speed and the higher‐level cognitive abilities this foundational skill supports. Brain growth and maturation rely on macronutrients and bioactive components provided by human milk, but the early‐life nutrition regimen to optimize processing speed remains unknown. What is New First postnatal month protein, lipid and energy intakes display sex‐specific associations with processing speed in 5‐year‐old preterm‐born children. Mother's milk provision during the first postnatal month is associated with higher processing speed scores. Early‐life nutrition is an intervention that may be leveraged to improve processing speed and sub