Extremely Preterm Infants Have a Higher Fat Mass Percentage in Comparison to Very Preterm Infants at Term-Equivalent Age

Impact of Nutrient Intake on Body Composition in Very Low-Birth Weight Infants Following Early Progressive Enteral Feeding

Preterm infants have increased body adiposity at term-equivalent age and risk of adverse metabolic outcomes. The aim of the study was to define how nutrient intake may impact body composition (BC) of very low-birth weight infants fed with early progressive enteral feeding and standard fortification. Eighty-six infants with <1500 g birth weight were included in the BC study and stratified into extremely preterm (EP) and very preterm (VP) groups. Nutrient intake was calculated during the first 28 days and BC assessed by dual X-ray absorptiometry at discharge and by skinfold thickness at 12 months of corrected age (CA). Total nutrient intake did not differ between the groups. EP infants had a higher fat mass percentage at discharge than VP infants (24.8% vs. 19.4%, p < 0.001); lean mass did not differ. None of the nutrients had any impact on BC of EP infants. Protein intake did not result in a higher lean mass in either group; fat intake was a significant predictor of increased fat mass percentage in VP infants at discharge (p = 0.007) and body adiposity at 12 months of CA (p = 0.021). Nutritional needs may depend on gestational age and routine fortification should be used with caution in more mature infants.

Individualized Fortification Based on Measured Macronutrient Content of Human Milk Improves Growth and Body Composition in Infants Born Less than 33 Weeks: A Mixed-Cohort Study

The optimal method for human milk (HM) fortification has not yet been determined. This study assessed whether fortification relying on measured HM macronutrient content (Miris AB analyzer, Upsala, Sweden) composition is superior to fortification based on assumed HM macronutrient content, to optimize the nutrition support, growth, and body composition in infants born at <33 weeks' gestation. In a mixed-cohort study, 57 infants fed fortified HM based on its measured content were compared with 58 infants fed fortified HM based on its assumed content, for a median of 28 and 23 exposure days, respectively. The ESPGHAN 2010 guidelines for preterm enteral nutrition were followed. Growth assessment was based on body weight, length, and head circumference Δ z-scores, and the respective growth velocities until discharge. Body composition was assessed using air displacement plethysmography. Fortification based on measured HM content provided significantly higher energy, fat, and carbohydrate intakes, although with a lower protein intake in infants weighing ≥ 1 kg and lower protein-to-energy ratio in infants weighing < 1 kg. Infants fed fortified HM based on its measured content were discharged with significantly better weight gain, length, and head growth. These infants had significantly lower adiposity and greater lean mass near term-equivalent age, despite receiving higher in-hospital energy and fat intakes, with a mean fat intake higher than the maximum recommended and a median protein-to-energy ratio intake (in infants weighing < 1 kg) lower than the minimum recommended.

Preterm birth and metabolic implications on later life: A narrative review focused on body composition

Preterm newborn infants are characterized by low body weight and lower fat mass at birth compared with full-term newborn neonates. Conversely, at term corrected age, body fat mass is more represented in preterm newborn infants, causing a predisposition to developing metabolic syndrome and cardiovascular diseases in later life with a different risk profile in men as compared with women. Postnatal growth is a complex change in anthropometric parameters and body composition. Both quantity and quality of growth are regulated by several factors such as fetal programming, early nutrition, and gut microbiota. Weight gain alone is not an optimal indicator of nutritional status as it does not accurately describe weight quality. The analysis of body composition represents a potentially useful tool to predict later metabolic and cardiovascular risk as it detects the quality of growth by differentiating between fat and lean mass. Longitudinal follow-up of preterm newborn infants could take advantage of body composition analysis in order to identify high-risk patients who apply early preventive strategies. This narrative review aimed to examine the state-of-the-art body composition among born preterm children, with a focus on those in the pre-school age group.

Early Life Factors Associated with Lean Body Mass in Spanish Children: CALINA Study

Early life is critical for the programming of body composition. The literature links perinatal factors with fat mass development and its future effects (e.g., obesity); however, little evidence exists between early life factors and lean body mass (LBM). This study follows up on a cohort of 416 Spanish children at ages six to eight, previously evaluated at birth in the CALINA study. Here, we studied the association between early life factors, LBM, and limb strength. Parental origin/nutritional status, maternal smoking during pregnancy, gestational diabetes/weight gain/age, birth weight (BW), early feeding, and rapid weight gain (RWG) were collected from primary care records. Bioimpedance analysis, dual-energy X-ray absorptiometry, peripheral quantitative computed tomography, and a handgrip/standing long jump test were used to assess fat-free mass index (FFMI), total lean soft tissue mass index (TLSTMI), muscle cross-sectional area index (MCSAI), and limb strength, respectively. In girls, maternal smoking, gestational age, and BW were positively associated with FFM/LSTM. In boys, the parents’ BMI, BW, and RWG were positively associated with FFM/LSTM. BW was associated with handgrip strength in both. Maternal BMI in girls and RWG in boys were negatively associated with the standing long jump. Early life programming plays a key role in determining LBM in children.

Body composition of extremely preterm infants fed protein-enriched, fortified milk: a randomized trial

BACKGROUND

Critically ill extremely preterm infants fed human milk are often underrepresented in neonatal nutrition trials aimed to determine the effects of enteral protein supplementation on body composition outcomes.

METHODS

Masked randomized trial in which 56 extremely preterm infants 25-28 weeks of gestation were randomized to receive either fortified milk enriched with a fixed amount of extensively hydrolyzed protein (high protein group) or fortified milk without additional protein (standard protein group).

RESULTS

Baseline characteristics were similar between groups. In a longitudinal analysis, the mean percent body fat (%BF) at 30-32 weeks of postmenstrual age (PMA), 36 weeks PMA, and 3 months of corrected age (CA) did not differ between groups (17 ± 3 vs. 15 ± 4; p = 0.09). The high protein group had higher weight (-0.1 ± 1.2 vs. -0.8 ± 1.3; p = 0.03) and length (-0.8 ± 1.3 vs. -1.5 ± 1.3; p = 0.02) z scores from birth to 3 months CA. The high protein group also had higher fat-free mass (FFM) z scores at 36 weeks PMA (-0.9 ± 1.1 vs. -1.5 ± 1.1; p = 0.04).

CONCLUSIONS

Increased enteral intake of protein increased FFM accretion, weight, and length in extremely preterm infants receiving protein-enriched, fortified human milk.

IMPACT

Extremely preterm infants are at high risk of developing postnatal growth failure, particularly when they have low fat-free mass gains. Protein supplementation increases fat-free mass accretion in infants, but several neonatal nutrition trials aimed to determine the effects of enteral protein supplementation on body composition outcomes have systematically excluded critically ill extremely preterm infants fed human milk exclusively. In extremely preterm infants fed fortified human milk, higher enteral protein intake increases fat-free mass accretion and promotes growth without causing excessive body fat accretion.

IGF-I, Growth, and Body Composition in Preterm Infants up to Term Equivalent Age

Context

There are concerns that a higher fat mass in the early life of preterm infants is associated with adverse cardiometabolic outcomes in young adulthood.

Objective

To investigate the role of IGF-I and growth in determining body composition of preterm infants at term equivalent age.

Methods

An observational study was conducted from August 2015 to August 2018. From birth to term equivalent age, IGF-I levels were measured bi-weekly and growth was assessed weekly. At term equivalent age, body composition was assessed through air displacement plethysmography; 65 infants with a gestational age of 24 to 32 weeks were assessed at term equivalent age, of whom 58 completed body composition measurement. The main outcome measures were fat (free) mass (g) and fat (free) mass percentage at term equivalent age.

Results

In the first month of life, each 0.1 nmol/L per week increase in IGF-I was associated with a 465 g (SE 125 g) increase in fat free mass. A greater increase in weight SDS in the first month of life was associated with a higher fat free mass percentage (B 200.9; 95% CI, 12.1-389.6). A higher head circumference SDS was associated with more fat free mass (r = 0.46; 95% CI, 0.21-0.65). However, a greater increase in weight SDS up to term equivalent age was associated with a lower fat free mass percentage (B -55.7, SE 9.4).

Conclusion

These findings suggest that impaired growth in the first month of life is associated with a less favorable body composition at term equivalent age.

Early Enteral Feeding in Preterm Infants: A Narrative Review of the Nutritional, Metabolic, and Developmental Benefits

Enteral feeding is the preferred method of nutrient provision for preterm infants. Though parenteral nutrition remains an alternative to provide critical nutrition after preterm delivery, the literature suggests that enteral feeding still confers significant nutritional and non-nutritional benefits. Therefore, the purpose of this narrative review is to summarize health and clinical benefits of early enteral feeding within the first month of life in preterm infants. Likewise, this review also proposes methods to improve enteral delivery in clinical care, including a proposal for decision-making of initiation and advancement of enteral feeding. An extensive literature review assessed enteral studies in preterm infants with subsequent outcomes. The findings support the early initiation and advancement of enteral feeding impact preterm infant health by enhancing micronutrient delivery, promoting intestinal development and maturation, stimulating microbiome development, reducing inflammation, and enhancing brain growth and neurodevelopment. Clinicians must consider these short- and long-term implications when caring for preterm infants.

Different feeding regimens were not associated with variation in body composition in preterm infants

AIM

The aim was to determine body composition and growth in preterm infants based on two different feeding regimens and to assess how standard and individual fortification (IF) affect energy and protein intake. Body composition was assessed at full term and at four months corrected age.

METHODS

Sixty preterm infants born before gestational week 32 were randomized either to IF of mother's breast milk after it had been analyzed or to standard fortification (SF) of mother's breast milk based on the average protein and energy content of breast milk. Body composition was measured at full term and at four months corrected age, using air displacement plethysmography. Growth rate and nutritional intake analyses were also conducted.

RESULTS

At 40 weeks gestational age, there was no difference between weight (g) (IF 3056 ± 472 vs. SF 3119 ± 564), body fat (%) (IF 19 ± 3.3 vs. SF 21 ± 5.6), fat mass, or fat-free mass between the two groups. Furthermore, there was no difference between the groups in weight, length, head circumference, or body composition at four months corrected age.

CONCLUSIONS

Fortification based on breast milk analysis may not improve growth in preterm infants compared to SF. However, both groups were smaller and had a different body composition at term corrected age compared to infants born at term.

Early weight gain trajectories and body composition in infancy in infants born very preterm

BACKGROUND

Concerns are raised about the influence of rapid growth on excessive fat mass (FM) gain in early life and later cardiometabolic health of infants born preterm.

OBJECTIVES

To study the association between postnatal weight gain trajectories and body composition in infancy in infants born very preterm.

METHODS

In infants born <30 weeks gestation, we evaluated associations between weight Z-score trajectories for three consecutive timeframes (NICU stay, level-II hospital stay and at home) and body composition, measured at 2 and 6 months corrected age by air-displacement plethysmography.

RESULTS

Of 120 infants included, median gestational age at birth was 27⁺⁵ (interquartile range 26⁺¹ ;28⁺⁵ ) and birth weight 1015 g (801;1250). The majority of infants did not make up for their initial loss of weight Z-score, but growth and later body composition were within term reference values. Weight gain during NICU stay was not associated with fat mass (absolute, %FM or FM index) in infancy. Weight gain during NICU and level II hospital stay was weakly associated with higher absolute lean mass (LM), but not after adjustment for length (LM index). Weight gain in the level-II hospital was positively associated with fat mass parameters at 2 months but not at 6 months. Strongest associations were found between weight gain at home and body composition (at both time points), especially fat mass.

CONCLUSIONS

Weight gain in different timeframes after preterm birth is associated with distinct parameters of body composition in infancy, with weight gain at home being most strongly related to fat mass.

Customized Human Milk Fortification Based on Measured Human Milk Composition to Improve the Quality of Growth in Very Preterm Infants: A Mixed-Cohort Study Protocol

Adequate nutrition of very preterm infants comprises fortification of human milk (HM), which helps to improve their nutrition and health. Standard HM fortification involves a fixed dose of a multi-nutrient HM fortifier, regardless of the composition of HM. This fortification method requires regular measurements of HM composition and has been suggested to be a more accurate fortification method. This observational study protocol is designed to assess whether the target HM fortification method (contemporary cohort) improves the energy and macronutrient intakes and the quality of growth of very preterm infants, compared with the previously used standard HM fortification (historical cohorts). In the contemporary cohort, a HM multi-nutrient fortifier and modular supplements of protein and fat are used for HM fortification, and the enteral nutrition recommendations of the European Society for Paediatric Gastroenterology Hepatology and Nutrition for preterm infants will be considered. For both cohorts, the composition of HM is assessed using the Miris Human Milk analyzer (Uppsala, Sweden). The quality of growth will be assessed by in-hospital weight, length, and head circumference growth velocities and a single measurement of adiposity (fat mass percentage and fat mass index) performed just after discharge, using the air displacement plethysmography method (Pea Pod, Cosmed, Italy). ClinicalTrials.gov registration number: NCT04400396.

Do preterm girls need different nutrition to preterm boys? Sex-specific nutrition for the preterm infant

Boys born preterm are recognised to be at higher risk of adverse outcomes than girls born preterm. Despite advances in neonatal intensive care and overall improvements in neonatal morbidity and mortality, boys born preterm continue to show worse short- and long-term outcomes than girls. Preterm birth presents a nutritional crisis during a critical developmental period, with postnatal undernutrition and growth-faltering common complications of neonatal intensive care. Furthermore, this preterm period corresponds to that of rapid in utero brain growth and development, and the developmental window relating to foetal programming of adult non-communicable diseases, the prevalence of which are associated both with preterm birth and sex. There is increasing evidence to show that from foetal life, boys and girls have different responses to maternal nutrition, that maternal breastmilk composition differs based on foetal sex and that early neonatal nutritional interventions affect boys and girls differently. This narrative review examines the evidence that sex is an important moderator of the outcomes of preterm nutrition intervention, and describes what further knowledge is required before providing nutrition intervention for infants born preterm based on their sex. IMPACT: This review examines the increasing evidence that boys and girls respond differently to nutritional stressors before birth, that maternal breastmilk composition differs by foetal sex and that nutritional interventions have different responses based on infant sex. Boys and girls born preterm are given standard nutritional support which does not take infant sex into account, and few studies of neonatal nutrition consider infant sex as a potential mediator of outcomes. By optimising early nutrition for boys and girls born preterm, we may improve outcomes for both sexes. We propose future studies of neonatal nutritional interventions should consider infant sex.

Protein Intakes during Weaning from Parenteral Nutrition Drive Growth Gain and Body Composition in Very Low Birth Weight Preterm Infants

Weaning from parenteral to enteral nutrition is a critical period to maintain an adequate growth in very low birth weight preterm infants (VLBWI). We evaluated the actual daily nutritional intakes during the transition phase (TP) in VLBWI with adequate and inadequate weight growth velocity (GV ≥ 15 vs. GV < 15 g/kg/day). Fat-free mass (FFM) at term-corrected age (TCA) was compared between groups. Based on actual nutritional intakes of infants with adequate growth, we defined a standardized parenteral nutrition bag (SPB) for the TP. One hundred and six VLBWI were categorized as group 1 (G1): [GV < 15 (n = 56)] and group 2 (G2): [GV ≥ 15 (n = 50)]. The TP was divided into two periods: main parenteral nutritional intakes period (parenteral nutritional intakes >50%) (M-PNI) and main enteral nutritional intakes period (enteral nutritional intakes >50%) (M-ENI). Anthropometric measurements were assessed at discharge and TCA, FFM deposition at TCA. During M-PNI, G2 showed higher enteral protein intake compared to G1 (p = 0.05). During M-ENI, G2 showed higher parenteral protein (p = 0.01) and energy intakes (p < 0.001). A gradual reduction in SPB volume, together with progressive increase in enteral volume, allowed nutritional intakes similar to those of G2. At TCA, G2 had higher FFM compared to G1 (p = 0.04). The reasoned use of SPB could guarantee an adequate protein administration, allowing an adequate growth and higher FFM deposition.