Association of haemoglobin levels in the first trimester and at 26-30 weeks with fetal and neonatal outcomes: a secondary analysis of the Global Network for Women's and Children's Health's ASPIRIN Trial.

OBJECTIVE: Limited data are available from low- and middle-income countries (LMICs) on the relationship of haemoglobin levels to adverse outcomes at different times during pregnancy. We evaluated the association of haemoglobin levels in nulliparous women at two times in pregnancy with pregnancy outcomes. DESIGN: ASPIRIN Trial data were used to study the association between haemoglobin levels measured at 6+0 -13+6  weeks and 26+0 -30+0  weeks of gestation with fetal and neonatal outcomes. SETTING: Obstetric care facilities in Pakistan, India, Kenya, Zambia, The Democratic Republic of the Congo and Guatemala. POPULATION: A total of 11 976 pregnant women. METHODS: Generalised linear models were used to obtain adjusted relative risks and 95% CI for adverse outcomes. MAIN OUTCOME MEASURES: Preterm birth, stillbirth, neonatal death, small for gestational age (SGA) and birthweight <2500 g. RESULTS: The mean haemoglobin levels at 6+0 -13+6  weeks and at 26-30 weeks of gestation were 116 g/l (SD 17) and 107 g/l (SD 15), respectively. In general, pregnancy outcomes were better with increasing haemoglobin. At 6+0 -13+6  weeks of gestation, stillbirth, SGA and birthweight <2500 g, were significantly associated with haemoglobin of 70-89 g/l compared with haemoglobin of 110-129 g/l The relationships of adverse pregnancy outcomes with various haemoglobin levels were more marked at 26-30 weeks of gestation. CONCLUSIONS: Both lower and some higher haemoglobin concentrations are associated with adverse fetal and neonatal outcomes at 6+0 -13+6  weeks and at 26-30 weeks of gestation, although the relationship with low haemoglobin levels appears more consistent and generally stronger. TWEETABLE ABSTRACT: Both lower and some higher haemoglobin concentrations were associated with adverse fetal and neonatal outcomes at 6-13 weeks and 26-30 weeks of gestation.

Bioactive components in human milk are differentially associated with rates of lean and fat mass deposition in infants of mothers with normal vs. elevated BMI.

OBJECTIVE: To model breastfed infant growth and body composition patterns over the first 4 months with multiple bioactive components of human milk (HM) and clinical factors (including maternal BMI status), which are related to growth. METHODS: Longitudinal observation of infant growth and body composition from 0 to 4 months among 41 predominantly breastfed infants (25 mothers of Normal-weight and 16 mothers with overweight/obesity). Fasted morning HM samples were collected at 5 time-points. Macronutrients, leptin, adiponectin, ghrelin, insulin, cytokines and n-6:n-3 esterified fatty acid ratio were measured. Infant weight-for-length Z-score (WLZ) trajectory, fat-free mass (FFM) gain, fat mass gain and %fat gain were modelled controlling for clinical covariates. RESULTS: HM insulin negatively associated with WLZ trajectory among infants of NW mothers (P = 0.028), but not associated with WLZ trajectory among infants of OW/Ob mothers. HM glucose (P < 0.001) was associated with slower rates of infant FFM gain. Infants of mothers with OW/Ob exhibited slower rates of FFM gain. HM protein, adiponectin and insulin concentrations, and n-6:n-3 ratio were all significant predictors in the model of infant fat mass gain (P < 0.03). Any amount of formula supplementation was associated with faster fat gain (P = 0.002). The model of %fat gain was similar to that of fat mass gain, excepting HM adiponectin was not a significant covariate, and a trend for maternal OW/Ob to correlate with faster %fat gain (P = 0.056). CONCLUSIONS: Bioactive components in HM may contribute to regulation of partitioning of body composition, and these contributions may differ between mothers of normal-weight vs. with OW/Ob.

Routine antenatal ultrasound in low- and middle-income countries: first look - a cluster randomised trial.

OBJECTIVE: Ultrasound is widely regarded as an important adjunct to antenatal care (ANC) to guide practice and reduce perinatal mortality. We assessed the impact of ANC ultrasound use at health centres in resource-limited countries. DESIGN: Cluster randomised trial. SETTING: Clusters within five countries (Democratic Republic of Congo, Guatemala, Kenya, Pakistan, and Zambia) METHODS: Clusters were randomised to standard ANC or standard care plus two ultrasounds and referral for complications. The study trained providers in intervention clusters to perform basic obstetric ultrasounds. MAIN OUTCOME MEASURES: The primary outcome was a composite of maternal mortality, maternal near-miss mortality, stillbirth, and neonatal mortality. RESULTS: During the 24-month trial, 28 intervention and 28 control clusters had 24 263 and 23 160 births, respectively; 78% in the intervention clusters received at least one study ultrasound; 60% received two. The prevalence of conditions noted including twins, placenta previa, and abnormal lie was within expected ranges. 9% were referred for an ultrasound-diagnosed condition, and 71% attended the referral. The ANC (RR 1.0 95% CI 1.00, 1.01) and hospital delivery rates for complicated pregnancies (RR 1.03 95% CI 0.89, 1.20) did not differ between intervention and control clusters nor did the composite outcome (RR 1.09 95% CI 0.97, 1.23) or its individual components. CONCLUSIONS: Despite availability of ultrasound at ANC in the intervention clusters, neither ANC nor hospital delivery for complicated pregnancies increased. The composite outcome and the individual components were not reduced. TWEETABLE ABSTRACT: Antenatal care ultrasound did not improve a composite outcome that included maternal, fetal, and neonatal mortality.

A prospective cause of death classification system for maternal deaths in low and middle-income countries: results from the Global Network Maternal Newborn Health Registry.

OBJECTIVE: To describe the causes of maternal death in a population-based cohort in six low- and middle-income countries using a standardised, hierarchical, algorithmic cause of death (COD) methodology. DESIGN: A population-based, prospective observational study. SETTING: Seven sites in six low- to middle-income countries including the Democratic Republic of the Congo (DRC), Guatemala, India (two sites), Kenya, Pakistan and Zambia. POPULATION: All deaths among pregnant women resident in the study sites from 2014 to December 2016. METHODS: For women who died, we used a standardised questionnaire to collect clinical data regarding maternal conditions present during pregnancy and delivery. These data were analysed using a computer-based algorithm to assign cause of maternal death based on the International Classification of Disease-Maternal Mortality system (trauma, termination of pregnancy-related, eclampsia, haemorrhage, pregnancy-related infection and medical conditions). We also compared the COD results to healthcare-provider-assigned maternal COD. MAIN OUTCOME MEASURES: Assigned causes of maternal mortality. RESULTS: Among 158 205 women, there were 221 maternal deaths. The most common algorithm-assigned maternal COD were obstetric haemorrhage (38.6%), pregnancy-related infection (26.4%) and pre-eclampsia/eclampsia (18.2%). Agreement between algorithm-assigned COD and COD assigned by healthcare providers ranged from 75% for haemorrhage to 25% for medical causes coincident to pregnancy. CONCLUSIONS: The major maternal COD in the Global Network sites were haemorrhage, pregnancy-related infection and pre-eclampsia/eclampsia. This system could allow public health programmes in low- and middle-income countries to generate transparent and comparable data for maternal COD across time or regions. TWEETABLE ABSTRACT: An algorithmic system for determining maternal cause of death in low-resource settings is described.

Global Network for Women's and Children's Health Research: probable causes of stillbirth in low- and middle-income countries using a prospectively defined classification system.

OBJECTIVE: We sought to classify causes of stillbirth for six low-middle-income countries using a prospectively defined algorithm. DESIGN: Prospective, observational study. SETTING: Communities in India, Pakistan, Guatemala, Democratic Republic of Congo, Zambia and Kenya. POPULATION: Pregnant women residing in defined study regions. METHODS: Basic data regarding conditions present during pregnancy and delivery were collected. Using these data, a computer-based hierarchal algorithm assigned cause of stillbirth. Causes included birth trauma, congenital anomaly, infection, asphyxia, and preterm birth, based on existing cause of death classifications and included contributing maternal conditions. MAIN OUTCOME MEASURES: Primary cause of stillbirth. RESULTS: Of 109 911 women who were enrolled and delivered (99% of those screened in pregnancy), 2847 had a stillbirth (a rate of 27.2 per 1000 births). Asphyxia was the cause of 46.6% of the stillbirths, followed by infection (20.8%), congenital anomalies (8.4%) and prematurity (6.6%). Among those caused by asphyxia, 38% had prolonged or obstructed labour, 19% antepartum haemorrhage and 18% pre-eclampsia/eclampsia. About two-thirds (67.4%) of the stillbirths did not have signs of maceration. CONCLUSIONS: Our algorithm determined cause of stillbirth from basic data obtained from lay-health providers. The major cause of stillbirth was fetal asphyxia associated with prolonged or obstructed labour, pre-eclampsia and antepartum haemorrhage. In the African sites, infection also was an important contributor to stillbirth. Using this algorithm, we documented cause of stillbirth and its trends to inform public health programs, using consistency, transparency, and comparability across time or regions with minimal burden on the healthcare system. TWEETABLE ABSTRACT: Major causes of stillbirth are asphyxia, pre-eclampsia and haemorrhage. Infections are important in Africa.

Human milk insulin is related to maternal plasma insulin and BMI: but other components of human milk do not differ by BMI.

BACKGROUND/OBJECTIVES: The impact of maternal BMI and insulin sensitivity on bioactive components of human milk (HM) is not well understood. As the prevalence of obesity and diabetes rises, it is increasingly critical that we understand how maternal BMI and hormones associated with metabolic disease relate to concentrations of bioactive components in HM. SUBJECTS/METHODS: This longitudinal cohort design followed 48 breastfeeding mothers through the first four months of lactation, collecting fasting morning HM samples at 2-weeks and 1, 2, 3 and 4-months, and fasting maternal blood at 2-weeks and 4-months. Insulin, glucose, adipokines leptin and adiponectin, appetite regulating hormone ghrelin, marker of oxidative stress 8OHdG and inflammatory cytokines (IL-6, IL-8, and TNF-a) were measured in HM and maternal plasma. RESULTS: A total of 26 normal weight (NW) (BMI=21.4±2.0 kg/m2) and 22 overweight/obese (OW/Ob) (BMI=30.4±4.2 kg/m2) were followed. Of all HM analytes measured, only insulin and leptin were different between groups - consistently higher in the OW/Ob group (leptin: P<0.001; insulin: P<0.03). HM insulin was 98% higher than maternal plasma insulin at 2-weeks and 32% higher at 4-months (P<0.001). Maternal fasting plasma insulin and HOMA-IR were positively related to HM insulin at 2-weeks (P<0.001, R2⩾0.38, n=31), and 4-months (P⩽0.005, R2⩾0.20, n=38). CONCLUSIONS: The concentrations of insulin in HM are higher than in maternal plasma and are related to maternal BMI and insulin sensitivity. With the exception of leptin, there were minimal other differences observed in HM composition across a wide range in maternal BMI.

Early infant adipose deposition is positively associated with the n-6 to n-3 fatty acid ratio in human milk independent of maternal BMI.

BACKGROUND/OBJECTIVES: Excessive infant weight gain in the first 6-month of life is a powerful predictor of childhood obesity and related health risks. In mice, omega-6 fatty acids (FAs) serve as potent ligands driving adipogenesis during early development. The ratio of omega-6 relative to omega-3 (n-6/n-3) FA in human milk (HM) has increased threefold over the last 30 years, but the impact of this shift on infant adipose development remains undetermined. This study investigated how maternal obesity and maternal dietary FA (as reflected in maternal red blood cells (RBCs) composition) influenced HM n-6 and n-3 FAs, and whether the HM n-6/n-3 ratio was associated with changes in infant adipose deposition between 2 weeks and 4 months postpartum. SUBJECTS/METHODS: Forty-eight infants from normal weight (NW), overweight (OW) and obese (OB) mothers were exclusively or predominantly breastfed over the first 4 months of lactation. Mid-feed HM and maternal RBC were collected at either transitional (2 weeks) or established (4 months) lactation, along with infant body composition assessed using air-displacement plethysmography. The FA composition of HM and maternal RBC was measured quantitatively by lipid mass spectrometry. RESULTS: In transitional and established HM, docosahexaenoic acid (DHA) was lower (P=0.008; 0.005) and the arachidonic acid (AA)/DHA+eicosapentaenoic acid (EPA) ratio was higher (P=0.05; 0.02) in the OB relative to the NW group. Maternal prepregnancy body mass index (BMI) and AA/DHA+EPA ratios in transitional and established HM were moderately correlated (P=0.018; 0.001). Total infant fat mass was increased in the upper AA/DHA+EPA tertile of established HM relative to the lower tertile (P=0.019). The amount of changes in infant fat mass and percentage of body fat were predicted by AA/EPA+DHA ratios in established HM (P=0.038; 0.010). CONCLUSIONS: Perinatal infant exposures to a high AA/EPA+DHA ratio during the first 4 months of life, which is primarily reflective of maternal dietary FA, may significantly contribute to the way infants accumulate adipose.

Zinc status and cognitive function of pregnant women in Southern Ethiopia.

The relation between zinc status and cognitive function was examined in a cross-sectional study in the Sidama area of Southern Ethiopia. Pregnant women >24 weeks of gestation from three adjacent rural villages volunteered to participate. Mean (s.d.) plasma zinc of 99 women was 6.97 (1.07) mumol/l (below the cutoff of 7.6 mumol/l indicative of zinc deficiency at this stage of gestation). The Raven's Coloured Progressive Matrices (CPM) test was administered individually. Scores for the Raven's scale A, which is the simplest scale, ranged from 4 to 10 of a possible 12. Women with plasma zinc <7.6 mumol/l had significantly lower Raven's CPM scale A scores than women with plasma zinc concentrations >7.6 mumol/l. Plasma zinc and maternal age and education predicted 17% of the variation in Raven's CPM scale A scores. We conclude that zinc deficiency is a major factor affecting cognition in these pregnant women.

Normal bone mineral density after treatment for childhood acute lymphoblastic leukemia diagnosed between 1991 and 1998.

OBJECTIVE: We investigated whether previous reports of reduced bone mineral density after management for childhood acute lymphoblastic leukemia (chALL) were confirmed in a more recently treated cohort. STUDY DESIGN: In a cross-sectional study 75 subjects who were given the diagnosis of chALL between January 1, 1991, and December 31, 1997 (69% standard, 31% high risk), at Denver Children's Hospital and who were 11 to 82 months post-diagnosis with no history of relapse, secondary malignancy, or transplant underwent whole body areal bone mineral densitometry (BMD(A) expressed as age- and sex-standardized z scores), a food frequency questionnaire, and a weight-bearing activity survey. RESULTS: Overall, the mean whole body BMD(A) z score was normal (+0.22 +/- 0.96). A significant positive association was found with whole body BMD(A) z score and years elapsed since the beginning of maintenance (linear regression coefficient = +0.2 Deltaz score/year; 95% CI = 0.09 to 0.3) after adjustment was done for risk status/age category, history of cranial radiation, and total days hospitalized. No association was found with high risk/older age at diagnosis, nutrient intake, chemotherapy dosage, or weight-bearing activity. CONCLUSION: Contrary to previous reports in which cranial radiation and longer hospitalizations were prominent components of therapy, our study suggests that more recently treated patients with chALL do not have persistent abnormalities of bone mineral density after completion of therapy.

Interrelationships of key variables of human zinc homeostasis: relevance to dietary zinc requirements.

Currently, estimates of human zinc requirements depend primarily on a factorial approach. The availability of tracer techniques employing zinc stable isotopes has facilitated the acquisition of data on major variables of zinc homeostasis in addition to those that can be measured with careful metabolic balance techniques. These data have promising potential to facilitate and improve the factorial approach. The thesis proposed in this paper is that realistic estimations of dietary zinc requirements by a factorial approach require attention to the dynamic interrelationships between major variables of zinc homeostasis. This applies especially to the positive relationship between endogenous fecal zinc and total absorbed zinc, which is the essential starting point in estimating physiologic and, from there, dietary requirements.

Bioavailability of dietary supplements and impact of physiologic state: infants, children and adolescents.

Bioavailability can be broadly defined as the absorption and utilization of a nutrient, both of which may be affected by such host factors as gender, physiologic state and coexisting pathologic conditions. This report highlights factors of particular importance for the bioavailability of nutrients for infants, children and adolescents. Considerations for nutrient bioavailability for pediatric populations include maturation of the gastrointestinal tract, growth, character of the diet, and nutritional status. Critical periods of development include early infancy (0-6 mo), late infancy/early childhood (6-24 mo) and adolescence (12-18 yr). Iron, zinc and calcium are minerals of particular interest and importance to pediatric populations and are susceptible to alterations in bioavailability. In the young infant, iron and zinc are highly bioavailable from human milk. By approximately 6 mo of age, other dietary sources are needed to maintain continued normal status. In breastfed infants who were born prematurely or with low birth weight, earlier supplemental iron is often recommended. For the older infant and toddler, iron and zinc are also important for normal growth and development. The bioavailability of these trace minerals in complementary foods is discussed. During adolescence, adequate calcium intake is critical to normal bone mineralization. In girls, peak calcium absorption and calcium deposition in bones occur at or near menarche, which illustrates the importance of the physiologic state on mineral bioavailability. Investigations into nutrient bioavailability must carefully consider these factors, because the failure to have well-matched comparison groups with respect to age and/or nutritional status may inadvertently mask differences in nutrient utilization.

Dietary phytate reduction improves zinc absorption in Malawian children recovering from tuberculosis but not in well children.

High dietary phytate content that compromises zinc nutriture is thought to be a major problem among children of the developing world. Zinc stable isotope techniques permit the quantitative assessment of the effect of phytate reduction on zinc homeostasis. We tested the hypothesis that zinc absorption would be increased in Malawian children fed a reduced-phytate corn-plus-soy diet compared with a standard high phytate diet. Twenty-three children hospitalized in Blantyre, Malawi, were enrolled. Children were selected from those recovering from tuberculosis and from well children (those with minor injuries, those awaiting elective surgery or healthy siblings). Children received a diet of corn-plus-soy porridge (either low phytate or high phytate) for a period of 3-7 d and then participated in a zinc stable isotope study. The study included the administration of oral and intravenous zinc stable isotopes and 7-d collections of urine and stool. The diet was maintained throughout the duration of specimen collection. Zinc isotopic enrichments in urine and stool were measured, and zinc fractional absorption, total zinc absorption, endogenous fecal zinc, net zinc retention and size of the exchangeable zinc pool were calculated. Among the 14 children recovering from tuberculosis, dietary phytate reduction resulted in higher fractional absorption (0.41 +/- 0.14 versus 0.24 +/- 0.09, mean +/- SD, P: < 0.05) and total zinc absorption (169 +/- 55 versus 100 +/- 46 microg/(kg. d), P: < 0.05). No effect of phytate reduction was seen in the well children (n = 9). Phytate reduction did not decrease the absolute endogenous fecal zinc, but it did decrease it relative to total absorbed zinc. These preliminary results indicate that phytate reduction may be beneficial in improving zinc nutriture in groups with increased zinc requirements who consume a cereal-based diet.

Development of a compartmental model of human zinc metabolism: identifiability and multiple studies analyses.

A compartmental model of zinc metabolism has been developed from stable isotope tracer studies of five healthy adults. Multiple isotope tracers were administered orally and intravenously, and the resulting enrichment was measured in plasma, erythrocytes, urine, and feces for as long as 3 wk. Data from total zinc measurements and model-independent calculations of various steady-state parameters were also modeled with the kinetic data. A structure comprised of 14 compartments and as many as 25 unknown kinetic parameters was developed to adequately model the data from each of the individual studies. The structural identifiability of the model was established using the GLOBI2 identifiability analysis software. Numerical identifiability of parameter estimates was evaluated using statistical data provided by SAAM. A majority of the model parameters was estimated with sufficient statistical certainty to be considered well determined. After the fitting of the model and data from the individual studies using SAAM/CONSAM, results were submitted to SAAM extended multiple studies analysis for aggregation into a single set of population parameters and statistics. The model was judged to be valid based on criteria described elsewhere.

Abnormalities in zinc homeostasis in young infants with cystic fibrosis.

Low plasma zinc concentrations have been reported in approximately 30% of young infants with cystic fibrosis identified by newborn screening. The objective of this study was to examine zinc homeostasis in this population by application of stable isotope methodology. Fifteen infants with cystic fibrosis (9 male, 6 female; 7 breast-fed, 8 formula-fed) were studied at a mean (+/-SD) age of 1.8 +/- 0.7 mo. On d 1, 70Zn was administered intravenously, and 67Zn was quantitatively administered with all human milk/formula feeds during the day. Three days later, a 3-d metabolic period was initiated, during which time intake was measured and complete urine and fecal collections were obtained. Fractional zinc absorption, total absorbed zinc, endogenous fecal zinc, and net absorbed zinc were measured; fecal fat excretion was also determined. Fractional absorption was significantly higher for the breast-fed infants (0.40 +/- 0.21) compared with the formula-fed group (0.13 +/- 0.06) (p = 0.01), but with the significantly higher dietary zinc intake of the formula-fed group, total absorbed zinc was higher for those receiving formula (p = 0.01). In 1 infants with complete zinc metabolic data, excretion of endogenous zinc was twofold greater for the formula-fed infants (p < 0.05); net absorption (mg zinc/d) was negative for both feeding groups: -0.04 +/- 0.52 for breast-fed; -0.28 +/- 0.57 for formula-fed. Endogenous fecal zinc losses correlated with fecal fat excretion (r = 0.89, n = 9, p = 0.001), suggesting interference with normal conservation of endogenously secreted zinc. These findings indicate impaired zinc homeostasis in this population and suggest an explanation for the observations of suboptimal zinc status in many young infants with cystic fibrosis prior to diagnosis and treatment.

Overview of zinc absorption and excretion in the human gastrointestinal tract.

Zinc homeostasis is primarily maintained via the gastrointestinal system by the processes of absorption of exogenous zinc and gastrointestinal secretion and excretion of endogenous zinc. Although these processes modulate net absorption and the size of the readily exchangeable zinc pools, there are limits to the effectiveness of the homeostatic mechanisms of these and other systems. As a result of the interplay of the subcellular regulation of these mechanisms and host, dietary and environmental factors, zinc deficiency is not uncommon, especially on a global basis. This overview briefly reviews current understanding about the subcellular mechanisms of zinc absorption and transport. Factors recognized to affect zinc absorption at the whole body level are reviewed and include the amount and form of zinc consumed; dietary promoters, such as animal protein and low-molecular-weight organic compounds; dietary inhibitors, such as phytate and possibly iron and calcium when consumed as supplements; and physiologic states, such as pregnancy, lactation and early infancy, all of which increase the demand for absorbed zinc. The control of endogenously secreted zinc is less well understood. Available data suggest that the quantity of secreted zinc with each meal may be considerable and that efficient reabsorption is critical to the maintenance of normal zinc balance. Factors that have been proposed to interfere with the normal reabsorption of endogenous zinc include phytate and unabsorbed fat. Understanding of the dietary, physiologic, pathologic and environmental factors that may adversely affect these processes, and therefore zinc homeostasis, will be critical to preventing and treating zinc deficiency in human populations.

Dietary zinc and iron sources, physical growth and cognitive development of breastfed infants.

Iron and zinc are trace minerals that are of critical importance to the young infant for normal growth and development. Exclusive feeding of human milk provides adequate amounts of both of these nutrients for normal term infants for approximately the first 6 mo. of life. Current recommendations for introduction of complementary foods at this age do not emphasize the order of introduction of specific foods because the infant's gastrointestinal tract is considered mature at this time. Consideration of nutritional needs at 6 mo. has generally focused on the increasing risk of iron deficiency the longer the diet is without an additional source of iron. Recently, there has been more recognition of the risk of zinc deficiency in the second half of the first year of life in breastfed infants. Review of common feeding practices indicates that early complementary foods are typically iron fortified but low in zinc. Several studies have now investigated the effects of meat as an earlier complementary food on iron and zinc status. Results of these studies, although requiring further verification, suggest that increased meat intake by breastfed infants >6 mo. old would adequately support both iron and zinc requirements.

Zinc homeostasis in healthy infants fed a casein hydrolysate formula.

BACKGROUND: The results of earlier, nonquantitative studies suggested that absorption of zinc from a semielemental (casein hydrolysate) formula was inferior to absorption from a cow's milk-based formula. The objective of this study was to compare fractional, total and net zinc absorption, and fecal excretion of endogenous zinc in the same healthy young infants when fed a casein hydrolysate versus cow's milk-based formula. METHODS: Fractional absorption of zinc and fecal excretion of endogenous zinc were determined from measurement of cumulative fecal excretion of unabsorbed tracer and by an isotope dilution technique, respectively, after oral administration of a 70Zn tracer with all formula feedings for 1 day. Six infants were assigned randomly to receive the test or control formula, and the other formula was administered 2 to 5 weeks later. RESULTS: Mean (+/-SD) fractional absorption of zinc from the casein hydrolysate formula (0.47 +/- 0.17) was double that from the cow's milk-based formula (0.22 +/- 0.04; P = 0.01) with a correspondingly greater total zinc absorption (3.23 +/- 1.67 mg Zn/day vs. 1.55 +/- 0.55 mg Zn/day; P = 0.05). Because the excretion of endogenous zinc in the feces did not differ between formulas (0.90 +/- 0.44 mg Zn/day vs. 0.91 +/- 0.29 mg Zn/day), net absorption of zinc was also higher with the casein hydrolysate formula (2.33 +/- 1.65 mg Zn/day vs. 0.81 +/- 0.67 mg Zn/day; P = 0.02). CONCLUSIONS: Retention of zinc appeared to be adequate to meet the needs for growth during feeding with cow's milk-based formula and was more than adequate during short-term feeding with the casein hydrolysate formula.

American Academy of Pediatrics. Committee on Nutrition. Calcium requirements of infants, children, and adolescents.

This statement is intended to provide pediatric caregivers with advice about the nutritional needs of calcium of infants, children, and adolescents. It will review the physiology of calcium metabolism and provide a review of the data about the relationship between calcium intake and bone growth and metabolism. In particular, it will focus on the large number of recent studies that have identified a relationship between childhood calcium intake and bone mineralization and the potential relationship of these data to fractures in adolescents and the development of osteoporosis in adulthood. The specific needs of children and adolescents with eating disorders are not considered.