The Impact of Homogenization on Donor Human Milk and Human Milk-Based Fortifiers and Implications for Preterm Infant Health

An exclusive human milk diet (EHMD) has been shown to reduce health complications of prematurity in infants born weighing ≤1250 grams compared to cow milk-based diets. Accordingly, the number of available human milk (HM)-based nutritional products continues to increase. Newly available products, and those reportedly soon to enter the market include homogenized donor human milk (DHM) and homogenized HM–based fortifiers. Existing literature demonstrating the benefits of an EHMD, however, is limited to non-homogenized HM-based products. Herein, we summarize existing evidence on the impact of homogenization on HM, with a particular focus on changes to the macromolecular structure of the milk fat globule and its subsequent impact on digestion kinetics. We use these published data to create a conceptual framework for the potential implications of homogenized HM-based nutritional products on preterm infant health. Importantly, we underscore that the safety and efficacy of homogenized HM-based products warrant investigation.

A Whole-Grain Diet Increases Whole-Body Protein Balance Compared to a Macronutrient-Matched Refined-Grain Diet

Background There are limited data from randomized control trials to support or refute the contention that whole-grains may enhance protein metabolism in humans. The objectives were threefold: 1) to examine the clinical effects of a whole-grain diet on whole-body protein turnover; 2) the cellular effects of whole-grains on protein synthesis in skeletal muscle cells; and 3) the population effects of whole-grain intake on age-related muscle loss. Methods Adults with overweight/obesity (N = 14, age: 40±7 years, BMI: 33±5 kg/m2) were recruited into a crossover, randomized controlled trial (NCT01411540) in which isocaloric, macronutrient-matched whole-grain and refined-grain diets were fully provisioned for two 8-week periods. Diets differed only in the presence of whole-grains (50 g/1000 kcal). Whole-body protein kinetics were assessed at baseline and after each diet in the fasted-state (13C-Leucine) and integrated over 24-hours (15N-Glycine). In vitro studies utilizing C2C12 cells assessed global protein synthesis by SUnSET and anabolic signaling by Western blot. Complementary epidemiologic assessments using the NHANES database assessed the effect of whole-grain intake on muscle function assessed by gait speed in older adults (N = 2,783). Results Integrated 24-hour net protein balance was 3-fold higher on a whole-grain compared to a refined-grain diet (P = 0.04). A whole-grain wheat extract increased submaximal rates of global protein synthesis (27%, P<0.05) in vitro. In a large sample of older adults, whole-grain intake was associated with greater muscle function in older adults (OR (CI) = 0.92 (0.86, 0.98)). Conclusions Consuming 50 g/1000 kcal of whole-grains per day promotes greater whole-body protein turnover and enhances net protein balance in adults. Whole-grains impact skeletal muscle at the cellular level, and in older adults, associate with greater muscle function. Collectively, these data point to a new mechanism whereby whole-grain consumption favorably enhances protein turnover and improves health outcomes.

Weight-For-Height Z-Score Gain During Inpatient And Subsequent Linear Growth During Outpatient Treatment Of Young Children With Severe Acute Malnutrition, A Prospective Study From Uganda

Background Linear catch-up growth after treatment of severe acute malnutrition (SAM) is low, and little is known about the association between ponderal and subsequent linear growth. Objective The study assessed the association of weight-for-height z-score (WHZ) gain with subsequent linear growth during SAM treatment and examined its modifiers. Methods This was a prospective study, nested in a trial (ISRCTN16454889), among 6–59-mo-old children treated for SAM in Uganda. Weight, total length (TL) and knee-heel length (KHL) were measured at admission, weekly during inpatient-therapeutic-care (ITC), at discharge and fortnightly during outpatient-therapeutic-care (OTC) for 8 weeks. Linear regression was used to assess the association between WHZ gain during ITC and linear growth during OTC. Results Of 400 children, 327 were discharged to OTC and 290 followed-up for 8 weeks. Mean WHZ gains were 0.45 in ITC and 1.24 in OTC, whereas mean height-for-age z-score (HAZ) declined 0.41 during ITC and increased 0.14 during OTC. WHZ gain during ITC was positively associated with HAZ, TL and KHL gains during OTC (regression coefficients (b) [95% CI]: (0.12 [0.09; 0.15] z-score; 3.1 [2.4; 3.8] mm; 0.5 [0.1; 0.7] mm). The regression coefficients were highest for the middle tertile of WHZ gain with respect to HAZ and TL. Admission diarrhea and low plasma citrulline reduced the association between WHZ gain during ITC and HAZ and TL gain during OTC (P < 0.001). In contrast, pneumonia (P = 0.051) and elevated plasma CRP (P < 0.001) increased the association with TL gain, but reduced the association with KHL gain (P < 0.001). Conclusion Among children admitted with SAM, considerable WHZ gain during ITC was followed by very modest linear catch-up growth during OTC, with no indication of a WHZ gain threshold, above which linear growth was higher. To optimize linear growth in these children, early treatment of infections and conditions affecting the gut may be necessary.

Sleep Disturbances, Obesity, and Cognitive Function in Childhood: A Mediation Analysis

Background Childhood cognitive development is influenced by biological and environmental factors. One such factor, obesity, impairs cognitive development and is associated with sleep disturbances (SDs). Objective To examine the mediating role of SDs on the relationship between body mass index (BMI) and cognitive function in children. Methods A total of 9951 children aged 9–10 years were included in this cross-sectional study. Children were recruited from the longitudinal Adolescent Brain Cognitive Development (ABCD) Study. Cognitive development was assessed using metrics for fluid, crystallized, and total cognitive function. Mediation analyses were conducted via linear regression modeling, with adjustment for potential confounders (sex, age, ethnicity, household income, parental education, and self-reported physical activity) for each of the three outcomes. Mediation significance was determined by bootstrapping. Results A statistically significant inverse association was found between BMI and total (β = −0.41, P < 0.001) and fluid (β = −0.49, P < 0.001) cognition, but not for crystallized cognition. Total sleep disturbances partially mediated the association between BMI and fluid cognition (indirect effect: -0.02, P = 0.002; proportion on the total effect: 0.05, P = 0.002), but no mediation was found in the association between BMI and total cognition. Conclusions Sleep disturbances partially mediate the effect of childhood obesity on cognitive function, particularly in fluid cognitions. Future work is necessary to understand the effects of sleep disturbances, and obesity on reduced childhood cognition throughout time, predominantly, across the life course.