Zinc and infant nutrition

Zinc is essential for a wide variety of cellular processes in all cells. It is a critical dietary nutrient, particularly in the early stages of life. In the early neonatal period, adequate sources of zinc can be obtained from breast milk. In rare circumstances, the mammary gland produces zinc deficient milk that is potentially lethal for exclusively breast-fed infants. This can be overcome by zinc supplementation to the infant. Alterations to key zinc transporters provide insights into the mechanisms of cellular zinc homeostasis. The bioavailability of zinc in food depends on the presence of constituents that may complex zinc. In many countries, zinc deficiency is a major health issue due to poor nourishment. Young children are particularly affected. Zinc deficiency can impair immune function and contributes to the global burden of infectious diseases including diarrhoea, pneumonia and malaria. Furthermore, zinc deficiency may extend its influence across generations by inducing epigenetic effects that alter the expression of genes. This review discusses the significance of adequate zinc nutrition in infants, factors that influence zinc nutrition, the consequences of zinc deficiency, including its contribution to the global burden of disease, and addresses some of the knowledge gaps in zinc biology.

Conservation of the ST6Gal I gene and its expression in the mammary gland

Milk sialoglycoconjugates can protect the gastrointestinal tract of the suckling neonate by competitively binding to invading pathogens and promoting growth of beneficial flora, and their potential role in postnatal brain development is of particular interest in human infant nutrition. Although the concentration and the distribution of sialoglycoconjugates have been extensively studied in the milk of various species, the investigation of sialyltransferase gene expression in the mammary gland, in the context of lactation, has been limited. The sialyltransferase enzyme ST6Gal I transfers sialic acid from CMP-sialic acid to type 2 (Galβ1,4GlcNAc) free disaccharides or the termini of N- or O-linked oligosaccharides using an α2,6-linkage. Expression of the ST6Gal I gene is primarily regulated at the level of transcription through the use of several cell and development- specific promoters, producing transcripts with divergent 5′ untranslated regions (UTR). In the mouse mammary gland, the novel 5′UTR exon (L) appears to be associated with a drastic increase in ST6Gal I gene expression during lactation. We find that rats also possess an exon (L), suggesting conservation of this regulatory mechanism in rodents. In contrast, an exon (L)-containing transcript was not detected in the lactating bovine or human mammary gland. We also observed a trend of increasing ST6Gal I gene expression in the bovine mammary gland, culminating in involution. This is in contrast to species such as mice where the greatest change in ST6Gal I gene expression occurs between pregnancy and lactation, suggesting different roles in rodents vs. other mammals for α2,6-sialylated oligosaccharides present in milk.

A review of the relationship between socioeconomic position and the early-life predictors of obesity

A range of important early-life predictors of later obesity have been identified. Children of lower socioeconomic position (SEP) have a steeper weight gain trajectory from birth with a strong socioeconomic gradient in child and adult obesity prevalence. An assessment of the association between SEP and the early-life predictors of obesity has been lacking. The review involved a two-stage process: Part 1, using previously published systematic reviews, we developed a list of the potentially modifiable determinants of obesity observable in the pre-natal, peri-natal or post-natal (pre-school) periods; and part 2, conducting a literature review of evidence for socioeconomic patterning in the determinants identified in part 1. Strong evidence was found for an inverse relationship between SEP and (1) pre-natal risk factors (pre-pregnancy maternal body mass index (BMI), diabetes and pre-pregnancy diet), (2) antenatal/peri natal risk factors (smoking during pregnancy and low birth weight) and (3) early-life nutrition (including breastfeeding initiation and duration, early introduction of solids, maternal and infant diet quality, and some aspects of the home food environment), and television viewing in young children. Less strong evidence (because of a lack of studies for some factors) was found for paternal BMI, maternal weight gain during pregnancy, child sleep duration, high birth weight and lack of physical activity in young children. A strong socioeconomic gradient exists for the majority of the early-life predictors of obesity suggesting that the die is cast very early in life (even pre-conception). Lifestyle interventions targeting disadvantaged women at or before child-bearing age may therefore be particularly important in reducing inequality. Given the likely challenges of reaching this target population, it may be that during pregnancy and their child's early years are more feasible windows for engagement.

The infant feeding activity and nutrition trial (INFANT) an early intervention to prevent childhood obesity : cluster-randomised controlled trial

Background : Multiple factors combine to support a compelling case for interventions that target the development of obesity-promoting behaviours (poor diet, low physical activity and high sedentary behaviour) from their inception. These factors include the rapidly increasing prevalence of fatness throughout childhood, the instigation of obesity-promoting behaviours in infancy, and the tracking of these behaviours from childhood through to adolescence and adulthood. The Infant Feeding Activity and Nutrition Trial (INFANT) aims to determine the effectiveness of an early childhood obesity prevention intervention delivered to first-time parents. The intervention, conducted with parents over the infant's first 18 months of life, will use existing social networks (first-time parent's groups) and an anticipatory guidance framework focusing on parenting skills which support the development of positive diet and physical activity behaviours, and reduced sedentary behaviours in infancy.

Methods/Design : This cluster-randomised controlled trial, with first-time parent groups as the unit of randomisation, will be conducted with a sample of 600 first-time parents and their newborn children who attend the first-time parents' group at Maternal and Child Health Centres. Using a two-stage sampling process, local government areas in Victoria, Australia will be randomly selected at the first stage. At the second stage, a proportional sample of first-time parent groups within selected local government areas will be randomly selected and invited to participate. Informed consent will be obtained and groups will then be randomly allocated to the intervention or control group.

Discussion : The early years hold promise as a time in which obesity prevention may be most effective. To our knowledge this will be the first randomised trial internationally to demonstrate whether an early health promotion program delivered to first-time parents in their existing social groups promotes healthy eating, physical activity and reduced sedentary behaviours. If proven to be effective, INFANT may protect children from the development of obesity and its associated social and economic costs.

Associations of maternal long-chain polyunsaturated fatty acids, methyl mercury, and infant development in the Seychelles Child Development Nutrition Study

Fish consumption during gestation can provide the fetus with long-chain polyunsaturated fatty acids (LCPUFA) and other nutrients essential for growth and development of the brain. However, fish consumption also exposes the fetus to the neurotoxicant, methyl mercury (MeHg). We studied the association between these fetal exposures and early child development in the Seychelles Child Development Nutrition Study (SCDNS). Specifically, we examined a priori models of Ω-3 and Ω-6 LCPUFA measures in maternal serum to test the hypothesis that these LCPUFA families before or after adjusting for prenatal MeHg exposure would reveal associations with child development assessed by the BSID-II at ages 9 and 30 months. There were 229 children with complete outcome and covariate data available for analysis. At 9 months, the PDI was positively associated with total Ω-3 LCPUFA and negatively associated with the ratio of Ω-6/Ω-3 LCPUFA. These associations were stronger in models adjusted for prenatal MeHg exposure. Secondary models suggested that the MeHg effect at 9 months varied by the ratio of Ω-6/Ω-3 LCPUFA. There were no significant associations between LCPUFA measures and the PDI at 30 months. There were significant adverse associations, however, between prenatal MeHg and the 30-month PDI when the LCPUFA measures were included in the regression analysis. The BSID-II mental developmental index (MDI) was not associated with any exposure variable. These data support the potential importance to child development of prenatal availability of Ω-3 LCPUFA present in fish and of LCPUFA in the overall diet. Furthermore, they indicate that the beneficial effects of LCPUFA can obscure the determination of adverse effects of prenatal MeHg exposure in longitudinal observational studies.

Iron intakes of Australian infants and toddlers: findings from the Melbourne Infant Feeding, Activity and Nutrition Trial (InFANT) Program

Fe deficiency remains the most common nutritional deficiency worldwide and young children are at particular risk. Preventative food-based strategies require knowledge of current intakes, sources of Fe, and factors associated with low Fe intakes; yet few data are available for Australian children under 2 years. This study’s objectives were to determine intakes and food sources of Fe for Australian infants and toddlers and identify non-dietary factors associated with Fe intake. Dietary, anthropometric and socio-demographic data from the Melbourne Infant Feeding, Activity and Nutrition Trial Program were analysed for 485 infants (mean age: 9·1 (sd 1·2) months) and 423 toddlers (mean age: 19·6 (sd 2·6) months) and their mothers. Dietary intakes were assessed via 24-h recalls over 3 non-consecutive days. Prevalence of inadequate Fe intake was estimated using the full probability approach. Associations between potential non-dietary predictors (sex, breast-feeding status, age when introduced to solid foods, maternal age, maternal education, maternal employment status and mother’s country of birth) and Fe intakes were assessed using linear regression. Mean Fe intakes were 9·1 (sd 4·3) mg/d for infants and 6·6 (sd 2·4) mg/d for toddlers. Our results showed that 32·6 % of infants and 18·6 % of toddlers had inadequate Fe intake. Main food sources of Fe were Fe-fortified infant formula and cereals for infants and toddlers, respectively. Female sex and current breast-feeding were negatively associated with infant Fe intakes. Introduction to solid foods at or later than 6 months was negatively associated with Fe intake in toddlers. These data may facilitate food-based interventions to improve Australian children’s Fe intake levels.

The extended Infant Feeding, Activity and Nutrition Trial (InFANT Extend) Program : a cluster-randomized controlled trial of an early intervention to prevent childhood obesity

BACKGROUND: Understanding how we can prevent childhood obesity in scalable and sustainable ways is imperative. Early RCT interventions focused on the first two years of life have shown promise however, differences in Body Mass Index between intervention and control groups diminish once the interventions cease. Innovative and cost-effective strategies seeking to continue to support parents to engender appropriate energy balance behaviours in young children need to be explored. METHODS/DESIGN: The Infant Feeding Activity and Nutrition Trial (InFANT) Extend Program builds on the early outcomes of the Melbourne InFANT Program. This cluster randomized controlled trial will test the efficacy of an extended (33 versus 15 month) and enhanced (use of web-based materials, and Facebook® engagement), version of the original Melbourne InFANT Program intervention in a new cohort. Outcomes at 36 months of age will be compared against the control group. DISCUSSION: This trial will provide important information regarding capacity and opportunities to maximize early childhood intervention effectiveness over the first three years of life. This study continues to build the evidence base regarding the design of cost-effective, scalable interventions to promote protective energy balance behaviors in early childhood, and in turn, promote improved child weight and health across the life course. TRIAL REGISTRATION: ACTRN12611000386932 . Registered 13 April 2011.

Influence of peers on breastfeeding discontinuation among new parents : the Melbourne InFANT Program

OBJECTIVE We aimed to investigate whether the proportion of breastfeeding mothers in first-time parent groups influenced the likelihood of ceasing breastfeeding and whether this was independent of socioeconomic position.
METHODS Data were from 501 mothers (from 62 first-time parent groups initiated ~6 weeks after birth) who provided data at the baseline and mid-intervention assessments of the Melbourne Infant Feeding, Activity, and Nutrition Trial. Parent groups were divided into those in which ≤25% of mothers had ceased breastfeeding by 6 weeks (low-cessation groups) and those in which >25% had ceased by 6 weeks (high-cessation groups).
RESULTS With the exclusion of mothers who had already ceased breastfeeding by 6 weeks, the proportion of mothers who ceased breastfeeding between the time of parent group initiation (6 weeks) and 6 months was higher in high-cessation groups than in low-cessation groups (37.4% vs 21.7%; P = .001). After adjustment for maternal age, BMI, employment, and education and area-level socioeconomic position, membership in a group in which a large proportion of mothers had ceased breastfeeding by 6 weeks was strongly related to cessation of breastfeeding before 6 months (odds ratio: 2.1 [95% confidence interval: 1.3–3.3]).
CONCLUSIONS Attendance at parent groups where peers are breastfeeding infants of a similar age may have an important influence on the continuation of breastfeeding to 6 months. First-time parent groups or other similar groups may be an important setting in which to promote the continuation of breastfeeding.