10-year cognition in preterms after random assignment to fatty acid supplementation in infancy

The effects of parenteral fish oil on neurodevelopment in preterm infants: A narrative review

OBJECTIVE

This narrative review aimed to summarize studies assessing the effects of parenteral fish oil on neurodevelopment in preterm infants.

METHODS

PubMed was searched (July 1985 to October 2023). We reviewed randomized controlled trials, and observational studies assessing intravenous lipid emulsion with fish oil in preterm infants (born less than 37 weeks' gestation), that reported long-term neurodevelopmental outcomes.

RESULTS

We identified four publications relating to three randomized controlled trials in addition to four cohort studies. Study designs and outcomes were heterogenous and precluded meta-analyses. Results of trials were null for a selection of neurodevelopmental outcomes, however possible benefits of parenteral fish oil supplementation for neurodevelopment was reported in three cohort studies. Certainty of the evidence is hindered by methodological limitations of available trials and observational studies.

CONCLUSIONS

Further research is required to firmly establish the effects of parenteral fish oil on preterm neurodevelopment.

A Systematic Review of Omega-3 Fatty Acid Consumption and Cognitive Outcomes in Neurodevelopment

INTRODUCTION

This systematic review addresses the effects of n-3 long-chain polyunsaturated fatty acids consumption on human neurodevelopment. It evaluates articles published between 2000 and 2022 investigating the cognitive outcomes during the period of neurodevelopment: from fetal development to adolescence. For the purpose of this review the terms LC PUFA and omega-3 fatty acid will be used interchangeably.

METHOD

Data were sourced from several major databases including PubMed (MEDLINE), Web of Science, and ProQuest Central. Randomized controlled trials (RCTs), nonrandomized controlled trials, prospective or retrospective cohort studies, and observational studies investigating the effects of omega-3 fatty acid consumption from dietary supplements, multiple-nutrient supplement, or food questionnaire on neurodevelopment were considered. Study population was separated in three developmental phases: (1) in-utero, (2) lactation/infancy, and (3) childhood/adolescence. Each article was evaluated for several key factors such as study type, type/dosage of PUFAs, number of subjects, length of intervention, participant age range, population characteristics, outcome measure (both primary/cognitive and secondary/other), results, conclusion, and confounding variables/limitations.

RESULTS

A total of 88 articles were included in the review, 69 RCTs and 19 longitudinal or observational studies. The results indicate equivocal effect of intervention, with some short-term benefits observed in the areas of visual attention, working memory, executive function, and communication. Omega-3 supplement might have a short-term positive impact on neurodevelopment in all three phases. Supplementation is recommended throughout life, rather than only during the earliest developmental stage.

Maternal and Neonatal Polyunsaturated Fatty Acid Intake and Risk of Neurodevelopmental Impairment in Premature Infants

The N3 and N6 long chain polyunsaturated fatty acids (LCPUFA) docosahexaenoic acid (DHA) and arachidonic acid (AA) are essential for proper neurodevelopment in early life. These fatty acids are passed from mother to infant via the placenta, accreting into fetal tissues such as brain and adipose tissue. Placental transfer of LCPUFA is highest in the final trimester, but this transfer is abruptly severed with premature birth. As such, efforts have been made to supplement the post-natal feed of premature infants with LCPUFA to improve neurodevelopmental outcomes. This narrative review analyzes the current body of evidence pertinent to neurodevelopmental outcomes after LCPUFA supplementation in prematurely born infants, which was identified via the reference lists of systematic and narrative reviews and PubMed search engine results. This review finds that, while the evidence is weakened by heterogeneity, it may be seen that feed comprising 0.3% DHA and 0.6% AA is associated with more positive neurodevelopmental outcomes than LCPUFA-deplete feed. While no new RCTs have been performed since the most recent Cochrane meta-analysis in 2016, this narrative review provides a wider commentary; the wider effects of LCPUFA supplementation in prematurely born infants, the physiology of LCPUFA accretion into preterm tissues, and the physiological effects of LCPUFA that affect neurodevelopment. We also discuss the roles of maternal LCPUFA status as a modifiable factor affecting the risk of preterm birth and infant neurodevelopmental outcomes. To better understand the role of LCPUFAs in infant neurodevelopment, future study designs must consider absolute and relative availabilities of all LCPUFA species and incorporate the LCPUFA status of both mother and infant in pre- and postnatal periods.

Nutrition and Brain Development

All nutrients are essential for brain development, but pre-clinical and clinical studies have revealed sensitive periods of brain development during which key nutrients are critical. An understanding of these nutrient-specific sensitive periods and the accompanying brain regions or processes that are developing can guide effective nutrition interventions as well as the choice of meaningful circuit-specific neurobehavioral tests to best determine outcome. For several nutrients including protein, iron, iodine, and choline, pre-clinical and clinical studies align to identify the same sensitive periods, while for other nutrients, such as long-chain polyunsaturated fatty acids, zinc, and vitamin D, pre-clinical models demonstrate benefit which is not consistently shown in clinical studies. This discordance of pre-clinical and clinical results is potentially due to key differences in the timing, dose, and/or duration of the nutritional intervention as well as the pre-existing nutritional status of the target population. In general, however, the optimal window of success for nutritional intervention to best support brain development is in late fetal and early postnatal life. Lack of essential nutrients during these times can lead to long-lasting dysfunction and significant loss of developmental potential.

Lipid Intake and Neurodevelopment in Preterm Infants

Preterm infants are born before the critical period of lipid accretion and brain development that occurs during the third trimester of pregnancy. Dietary lipids serve as an important source of energy and are involved in complex processes that are essential for normal central nervous system development. In addition to traditional neurodevelopmental testing, novel quantitative magnetic resonance imaging (MRI) techniques are now available to evaluate the impact of nutritional interventions on early preterm brain development. Trials of long-chain polyunsaturated fatty acid supplementation have yielded inconsistent effects on neurodevelopmental outcomes and quantitative MRI findings. Recent studies using quantitative MRI suggest a positive impact of early lipid intake on brain volumes and white matter microstructural organization by term-equivalent age.

Perinatal Dietary Polyunsaturated Fatty Acids in Brain Development, Role in Neurodevelopmental Disorders

n-3 and n-6 polyunsaturated fatty acids (PUFAs) are essential fatty acids that are provided by dietary intake. Growing evidence suggests that n-3 and n-6 PUFAs are paramount for brain functions. They constitute crucial elements of cellular membranes, especially in the brain. They are the precursors of several metabolites with different effects on inflammation and neuron outgrowth. Overall, long-chain PUFAs accumulate in the offspring brain during the embryonic and post-natal periods. In this review, we discuss how they accumulate in the developing brain, considering the maternal dietary supply, the polymorphisms of genes involved in their metabolism, and the differences linked to gender. We also report the mechanisms linking their bioavailability in the developing brain, their transfer from the mother to the embryo through the placenta, and their role in brain development. In addition, data on the potential role of altered bioavailability of long-chain n-3 PUFAs in the etiologies of neurodevelopmental diseases, such as autism, attention deficit and hyperactivity disorder, and schizophrenia, are reviewed.

The Influence of Omega-3 Long-Chain Polyunsaturated Fatty Acid, Docosahexaenoic Acid, on Child Behavioral Functioning: A Review of Randomized Controlled Trials of DHA Supplementation in Pregnancy, the Neonatal Period and Infancy

This is a review of randomized controlled trials using docosahexaenoic acid (DHA) interventions in the first 1000 days of life with assessments of behavioral functioning in childhood. Electronic databases were searched for trials with a DHA intervention (compared with a placebo group that received no or less DHA) at any time to either women or infants during the first 1000 days, with a subsequent assessment of child behavior. There were 25 trials involving 10,320 mother–child pairs, and 71 assessments of behavior in 6867 of the children (66.5% of those originally enrolled). From the 71 assessments administered, there were 401 comparisons between a DHA group and a control group, with most reporting a null effect. There were no findings of a positive effect of DHA, and 23 instances where the DHA group had worse scores compared with the control group. There was limited evidence that DHA supplementation had any effect on behavioral development, although two of the largest trials with behavioral measures detected adverse effects. Future trials, and future follow-ups of existing trials, should make an effort to evaluate the effect of DHA intervention on behavioral functioning.

Maternal Docosahexaenoic Acid Status during Pregnancy and Its Impact on Infant Neurodevelopment

Dietary components are essential for the structural and functional development of the brain. Among these, docosahexaenoic acid, 22:6n-3 (DHA), is critically necessary for the structure and development of the growing fetal brain in utero. DHA is the major n-3 long-chain polyunsaturated fatty acid in brain gray matter representing about 15% of all fatty acids in the human frontal cortex. DHA affects neurogenesis, neurotransmitter, synaptic plasticity and transmission, and signal transduction in the brain. Data from human and animal studies suggest that adequate levels of DHA in neural membranes are required for maturation of cortical astrocyte, neurovascular coupling, and glucose uptake and metabolism. Besides, some metabolites of DHA protect from oxidative tissue injury and stress in the brain. A low DHA level in the brain results in behavioral changes and is associated with learning difficulties and dementia. In humans, the third trimester-placental supply of maternal DHA to the growing fetus is critically important as the growing brain obligatory requires DHA during this window period. Besides, DHA is also involved in the early placentation process, essential for placental development. This underscores the importance of maternal intake of DHA for the structural and functional development of the brain. This review describes DHA’s multiple roles during gestation, lactation, and the consequences of its lower intake during pregnancy and postnatally on the 2019 brain development and function.

Effect of long-chain polyunsaturated fatty acids in infant formula on long-term cognitive function in childhood: A systematic review and meta-analysis of randomised controlled trials

STUDY REGISTRATION

PROSPERO registration numbers CRD42018105196 and CRD42018088868.

The Influence of DHA on Language Development: A Review of Randomized Controlled Trials of DHA Supplementation in Pregnancy, the Neonatal Period, and Infancy

This review summarizes randomized controlled trials (RCTs) assessing the effect of docosahexaenoic acid (DHA) supplementation in the first 1000 days on child language. Six databases were searched and RCTs were included if they involved supplementation with DHA during pregnancy, to preterm infants, or during the postpartum period, included a placebo group with less or no DHA, and reported a language outcome. We included 29 RCTs involving n = 10,405 participants from 49 publications. There was a total of 84 language measures at ages ranging from 3 months to 12 years. Of the 84 assessments, there were 4 instances where the DHA group had improved scores, and 2 instances where the DHA group had worse scores (with the majority of these significant effects found within one RCT). The remaining comparisons were null. A few RCTs that included subgroup analyses reported (inconsistent) effects. There was limited evidence that DHA supplementation had any effect on language development, although there were some rare instances of both possible positive and adverse effects, particularly within population subgroups. It is important that any subgroup effects are verified in future trials that are adequately powered to confirm such effects.

DHA supplementation in infants born preterm and the effect on attention at 18 months' corrected age: follow-up of a subset of the N3RO randomised controlled trial

Infants born preterm miss out on the peak period of in utero DHA accretion to the brain during the last trimester of pregnancy which is hypothesised to contribute to the increased prevalence of neurodevelopmental deficits in this population. This study aimed to determine whether DHA supplementation in infants born preterm improves attention at 18 months' corrected age. This is a follow-up of a subset of infants who participated in the N3RO randomised controlled trial. Infants were randomised to receive an enteral emulsion of high-dose DHA (60 mg/kg per d) or no DHA (soya oil - control) from within the first days of birth until 36 weeks' post-menstrual age. The assessment of attention involved three tasks requiring the child to maintain attention on toy/s in either the presence or absence of competition or a distractor. The primary outcome was the child's latency of distractibility when attention was focused on a toy. The primary outcome was available for seventy-three of the 120 infants that were eligible to participate. There was no evidence of a difference between groups in the latency of distractibility (adjusted mean difference: 0·08 s, 95 % CI -0·81, 0·97; P = 0·86). Enteral DHA supplementation did not result in improved attention in infants born preterm at 18 months' corrected age.

The role of long chain polyunsaturated fatty acids in perinatal nutrition

The importance of omega-3 long chain polyunsaturated fatty acids in the perinatal period has been the focus of research for several decades. Infants born preterm miss out on the last trimester in utero transfer of omega-3 fatty acids and consequently have lower blood levels than infants born at term. Preterm infant formula was supplemented with the omega-3 docosahexaenoic acid and the omega-6 arachidonic acid from 2000 (to the level found in the breast milk of women consuming a western diet) based on trials reporting improvements in visual acuity. Docosahexaenoic acid supplementation beyond this level has not shown improvements in clinical or developmental outcomes, however the effect on childhood development in the most preterm infants remains to be resolved. Maternal omega-3 supplementation during pregnancy has the potential to reduce the incidence of preterm birth but may also, in some pregnancies, prolong gestation beyond term and increase fetal size.

Early caloric deprivation in preterm infants affects Bayley-III scales performance at 18-24 months of corrected age

BACKGROUND

Adequate nutrition is essential for optimal neurodevelopment to preterm infants. Our aim was to evaluate the impact of caloric deprivation on Bayley-III scales performance at 18-24 months of corrected age, in a cohort of preterm infants.

METHODS

We prospectively enrolled infants with gestational age <30 weeks and birth weight <1500 g. Apart from a whole cohort analysis, we performed a subgroup analysis between infants received inadequate calories (<85 Kcal/kg/day) during the first two weeks of age, compared to a standard nutrition group. All infants underwent a Bayley-III assessment at 18-24 months of corrected age.

RESULTS

From the 63 preterm infants analysed, 25% had caloric deprivation compared to 75% with adequate nutrition. Caloric deprived infants were of lower gestational age and birth weight, and received a lower amount of enteral feeding during the first 14 days of age. There were no differences between the two groups regarding the common neonatal co-morbidities. Caloric deprived infants had significantly lower composite index scores at 18-24 months of corrected age. Caloric deprivation, late onset sepsis, necrotizing enterocolitis, and bronchopulmonary dysplasia were significant risk factors of neurodevelopmental impairment.

CONCLUSIONS

Several neonatal factors affect the neurodevelopmental outcome of preterm infants, and nutrition may pose an important role.

Fish, Shellfish, and Children's Health: An Assessment of Benefits, Risks, and Sustainability

American children eat relatively little fish and shellfish in comparison with other sources of animal protein, despite the health benefits that eating fish and shellfish may confer. At the same time, fish and shellfish may be sources of toxicants. This report serves to inform pediatricians about available research that elucidates health risks and benefits associated with fish and shellfish consumption in childhood as well as the sustainability of fish and shellfish harvests.

A More Comprehensive Approach to the Neuroprotective Potential of Long-Chain Polyunsaturated Fatty Acids in Preterm Infants Is Needed-Should We Consider Maternal Diet and the n-6:n-3 Fatty Acid Ratio?

There is growing evidence that long-chain polyunsaturated fatty acids (LCPUFAs) are of importance for normal brain development. Adequate supply of LCPUFAs may be particularly important for preterm infants, because the third trimester is an important period of brain growth and accumulation of arachidonic acid (n-6 LCPUFA) and docosahexaenoic acid (n-3 LCPUFA). Fatty acids from the n-6 and n-3 series, particularly, have important functions in the brain as well as in the immune system, and their absolute and relative intakes may alter both the risk of impaired neurodevelopment and response to injury. This narrative review focuses on the potential importance of the n-6:n-3 fatty acid ratio in preterm brain development. Randomized trials of post-natal LCPUFA supplementation in preterm infants are presented. Pre-clinical evidence, results from observational studies in preterm infants as well as studies in term infants and evidence related to maternal diet during pregnancy, focusing on the n-6:n-3 fatty acid ratio, are also summarized. Two randomized trials in preterm infants have compared different ratios of arachidonic acid and docosahexaenoic acid intakes. Most of the other studies in preterm infants have compared formula supplemented with arachidonic acid and docosahexaenoic acid to un-supplemented formula. No trial has had a comprehensive approach to differences in total intake of both n-6 and n-3 fatty acids during a longer period of neurodevelopment. The results from preclinical and clinical studies indicate that intake of LCPUFAs during pregnancy and post-natal development is of importance for neurodevelopment and neuroprotection in preterm infants, but the interplay between fatty acids and their metabolites is complex. The best clinical approach to LCPUFA supplementation and n-6 to n-3 fatty acid ratio is still far from evident, and requires in-depth future studies that investigate specific fatty acid supplementation in the context of other fatty acids in the diet.

Neurodevelopmental outcome of nutritional intervention in newborn infants at risk of neurodevelopmental impairment: the Dolphin neonatal double-blind randomized controlled trial

AIM

To investigate whether neonates at risk for neurodevelopmental impairment have improved neurodevelopment after docosahexaenoic acid, choline, and uridine-5-monophosphate supplementation versus controls.

METHOD

Recruitment was from UK neonatal units. Eligible for inclusion were infants born at less than 31 weeks' gestation with a weight less than the ninth centile; infants born at less than 31 weeks' gestation with a grade II or higher intraventricular haemorrhage/preterm white matter injury; infants born between 31 weeks' and 40 weeks' gestation plus 28 days with a grade II or higher intraventricular haemorrhage/preterm white matter injury, moderate or severe hypoxic-ischaemic encephalopathy, or defined neuroimaging abnormalities. Treatment/control supplementation was for 2 years (double-blind, randomized, controlled design). Infants were stratified according to sex, gestation, and brain injury severity. Primary outcome was cognitive composite score (CCS) of the Bayley Scales of Infant Development, Third Edition (Bayley-III at 24mo). Secondary outcomes were language composite score (LCS) of the Bayley-III, motor composite score (MCS) of the Bayley-III, and Vineland Adaptive Behaviour Scales, Second Edition (VABS-II) score.

RESULTS

Sixty-two neonates were recruited, 59 were randomized (34 males, 25 females). Fifty-three started supplementation. Most families found supplementation acceptable. The treatment group CCS-Bayley-III scores were non-significantly higher than controls (mean score difference at 24mo: 9.0; 95% confidence interval -0.2 to 18.2). Language and VABS-II scores, but not motor score, were non-significantly higher in the treatment group.

INTERPRETATION

Most families found supplementation feasible. Improved neurodevelopmental outcomes in the treatment group were not statistically significant. A larger multicentre trial exploration is warranted.

WHAT THIS PAPER ADDS

Dietary supplementation of neonates at risk of neurodevelopmental impairment is feasible. No statistically significant neurodevelopmental advantages were identified for the treatment group compared to controls. Treatment group cognitive and language advantage are of a clinically meaningful magnitude.

The effect of long chain polyunsaturated fatty acid supplementation on intelligence in low birth weight infant during lactation: A meta-analysis

Background

Low birth weight infant (LBWIs) are prone to mental and behavioural problems. As an important constituent of the brain and retina, long chain polyunsaturated fatty acids are essential for foetal infant mental and visual development. The effect of lactation supplemented with long chain polyunsaturated fatty acids (LCPUFA) on the improvement of intelligence in low birth weight children requires further validation.

Methods

In this study, a comprehensive search of multiple databases was performed to identify studies focused the association between intelligence and long chain polyunsaturated fatty acid supplementation in LBWIs. Studies that compared the Bayley Scales of Infant Development (BSID) or the Wechsler Abbreviated Scale of Intelligence for Children (WISC) scores between LBWIs who were supplemented and controls that were not supplemented with LCPUFA during lactation were selected for inclusion in the meta-analysis.

Results

The main outcome was the mean difference in the mental development index (MDI) and psychomotor development index (PDI) of the BSID and the full scale intelligence quotient (FSIQ), verbal intelligence quotient (VIQ) and performance intelligence quotient (PIQ) of the WISC between LBWIs and controls. Our findings indicated that the mean BSID or WISC scores in LBWIs did not differ between the supplemented groups and controls.

Conclusion

This meta-analysis does not reveal that LCPUFA supplementation has a significant impact on the level of intelligence in LBWIs.

n-3 Fatty Acid Supplementation in Mothers, Preterm Infants, and Term Infants and Childhood Psychomotor and Visual Development: A Systematic Review and Meta-Analysis

Background

Epidemiologic studies link maternal seafood and n-3 (ω-3) polyunsaturated fatty acid (PUFA) consumption with improved childhood cognitive development; trials show mixed results.

Objective

We investigated effects of n-3 PUFA supplementation on child cognitive and visual outcomes.

Methods

We systematically reviewed and meta-analyzed randomized controlled trials of n-3 PUFA supplementation in mothers or infants (age ≤2 y) and evaluated standardized measures of cognitive or visual development up to age 18 y. Of 6286 abstracts and 669 full-text articles, 38 trials with 53 intervention arms were included. Data were extracted independently in duplicate. Findings were pooled using random-effects meta-analysis across supplementation periods (maternal, preterm, term infant); we also explored subgroup analyses stratified by supplementation period. Heterogeneity was explored using I2, stratified analysis, and meta-regression. Cognitive development was assessed by Bayley Scales of Infant Development mental and psychomotor developmental indexes (MDI, PDI) and intelligence quotient (IQ); visual acuity was assessed by electrophysiological or behavioral measures.

Results

The 38 trials (mothers: n = 13; preterm infants: n = 7; term infants: n = 18) included 5541 participants. When we explored effects during different periods of supplementation, n-3 PUFA supplementation improved MDI in preterm infants (3.33; 95% CI: 0.72, 5.93), without statistically significant effects on PDI or IQ in different intervention period subgroups. Visual acuity [measured as the logarithm of the minimum angle of resolution (logMAR)] was improved by supplementation in preterm (-0.08 logMAR; 95% CI: -0.14, -0.01 logMAR) and term infants (-0.08 logMAR; 95% CI: -0.11, -0.05 logMAR), with a nonsignificant trend for maternal supplementation (-0.02 logMAR; 95% CI: -0.04, 0.00 logMAR). In main analyses pooling all supplementation periods, compared with placebo, n-3 PUFA supplementation improved MDI (n = 21 trials; 0.91; 95% CI: 0.005, 1.81; P = 0.049), PDI (n = 21 trials; 1.06 higher index; 95% CI: 0.10, 2.03; P = 0.031), and visual acuity (n = 24; -0.063 logMAR; 95% CI: -0.084, -0.041 logMAR; P < 0.001) but not IQ (n = 7; 0.20; 95% CI: -1.56, 1.96, P = 0.83), although few studies assessed this endpoint. Potential publication bias was identified for MDI (Eggers P = 0.005), but not other endpoints. Significant differences in findings were not identified by world region, race, maternal education, age at outcome assessment, supplementation duration, DHA or EPA dose, DHA:AA ratio, or study quality score (P-interaction > 0.05 each).

Conclusions

n-3 PUFA supplementation improves childhood psychomotor and visual development, without significant effects on global IQ later in childhood, although the latter conclusion is based on fewer studies.

Different concentrations of docosahexanoic acid supplement during lactation result in different outcomes in preterm Sprague-Dawley rats

PROPOSE

In this study, we evaluated the effects of different concentrations of docosahexanoic acid (DHA) supplement on preterm Sprague-Dawley rat pups, and in parallel, measured the phosphorylation activity of the mTOR pathway in the hippocampal CA1 area.

METHODS

Preterm Sprague-Dawley rat pups were randomly assigned to experimental groups which included; a sufficient DHA group (100 mg/kg/day); an enriched DHA group (300 mg/kg/day); an excess DHA group (800 mg/kg/day); and a deficient DHA group (normal saline gavage 0.1 ml/10 g). Body weight (g) was measured at days 1/7/14/21/28/42, respectively. Spatial learning and memory were also tested using the Morris water maze at week 6 (day 42). Finally, activation of the mTOR signaling pathway in hippocampal CA1 area were evaluated by western blotting.

RESULTS

Postnatal sufficient/enriched docosahexanoic acid supplement ameliorated body weight restriction, spatial learning and memory restriction, and decreased phosphorylation of AKT, mTOR, P70S6K1, and 4EBP1 in hippocampal CA1 area. Furthermore, excess docosahexanoic acid supplement impeded weight gain and spatial learning and memory, perturbed serum unsaturated fatty acid, and downregulated phosphorylation of AKT, mTOR, P70S6K1, and 4EBP1 in hippocampal CA1 area.

CONCLUSION

Postnatal sufficient/enriched DHA supplement ameliorated growth and spatial learning and memory impairment and upregulated the mTOR pathway in preterm pups, although excessive DHA supplement did not have any beneficial effects.

Docosahexaenoic acid (DHA), a fundamental fatty acid for the brain: New dietary sources

Docosahexaenoic acid (C22: 6n-3, DHA) is a long-chain polyunsaturated fatty acid of marine origin fundamental for the formation and function of the nervous system, particularly the brain and the retina of humans. It has been proposed a remarkable role of DHA during human evolution, mainly on the growth and development of the brain. Currently, DHA is considered a critical nutrient during pregnancy and breastfeeding due their active participation in the development of the nervous system in early life. DHA and specifically one of its derivatives known as neuroprotectin D-1 (NPD-1), has neuroprotective properties against brain aging, neurodegenerative diseases and injury caused after brain ischemia-reperfusion episodes. This paper discusses the importance of DHA in the human brain given its relevance in the development of the tissue and as neuroprotective agent. It is also included a critical view about the ways to supply this noble fatty acid to the population.

Cortisol in Neonatal Mother's Milk Predicts Later Infant Social and Cognitive Functioning in Rhesus Monkeys

Milk provides not only the building blocks for somatic development but also the hormonal signals that contribute to the biopsychological organization of the infant. Among mammals, glucocorticoids (GCs) in mother's milk have been associated with infant temperament. This study extended prior work to investigate rhesus monkey (Macaca mulatta) mother-infant dyads (N = 34) from birth through 8 months postpartum. Regression analysis revealed that cortisol concentrations in milk during the neonatal period predicted impulsivity on a cognitive task, but not global social behaviors, months later. During this time period, sex-differentiated social behavior emerged. For female infants, milk cortisol concentrations predicted total frequency of play. Collectively, these findings support and extend the "lactational programming" hypothesis on the impact of maternal-origin hormones ingested via milk.

Patterns of Early-Life Social and Environmental Exposures and Child Cognitive Development, Rhea Birth Cohort, Crete, Greece

Early-life exposures are critical for later child cognitive development. McCarthy Scales of Children's Abilities (MSCA) were used to assess cognitive development of 700 preschoolers (M_age  = 4.2 years), derived from the "Rhea" birth cohort, in Greece. Principal component analysis (PCA) was applied on prospectively collected exposure data. Six components were extracted; five of them were associated with child cognition. Higher parental social status, preschool attendance and less TV watching, nonsmoking during pregnancy and breastfeeding, and parental involvement in child life were protective factors of child cognition at 4 years. Increased child birth order was negatively associated with child cognition. Offspring's size at birth was not associated with any cognitive outcome. These findings reveal the importance of early-life exposures to child cognitive development.

Neurodevelopmental Outcomes of Preterm Infants Fed Human Milk: A Systematic Review

The neurodevelopmental benefits of breast milk feedings for preterm infants have been controversial. However, the effect on preterm infant neurodevelopment is sustained into childhood. The effects of breast milk feeding during the neonatal period and the duration of breastfeeding display effects on cognition into adolescence. The volume of breast milk received is a key factor in these effects. Additionally, emerging studies support the effects of human milk on structural brain development, such as increased white matter development and increased cortical thickness. The components of breast milk thought to mediate improved cognitive outcomes include long-chain polyunsaturated fatty acids and human milk oligosaccharides.

Early Nutritional Interventions for Brain and Cognitive Development in Preterm Infants: A Review of the Literature

Adequate nutrition is important for neurodevelopmental outcomes in preterm-born infants. In this review, we aim to summarize the current knowledge on nutritional interventions initiated during the hospital stay targeting brain and cognitive development benefits in preterm human infants. Studies can broadly be split in general dietary intervention studies and studies investigating specific nutrients or nutritional supplements. In general, mother's breast milk was reported to be better for preterm infants' neurodevelopment compared to infant formula. The differences in methodologies make it difficult to conclude any effects of interventions with individual nutrients. Only protein and iron level studies showed some consistent findings regarding optimal doses; however, confirmatory studies are needed. This review does not support some widely accepted associations, such as that between long-chain polyunsaturated fatty acid supplementation and visual development. Clear nutritional recommendations cannot be made based on this review. However, the type of infant nutrition (i.e., breast milk versus formula or donor milk), the timing of the nutritional intervention, and the dose of the nutrient/supplement have been found to be relevant factors in determining the success of nutritional intervention studies in preterm infants.

Fit with good fat? The role of n-3 polyunsaturated fatty acids on exercise performance

N-3 PUFA (n-3) polyunsaturated fatty acids (PUFA) are a family of fatty acids mainly found in oily fish and fish oil supplements. The effects of n-3 PUFA on health are mainly derived from its anti-inflammatory proprieties and its influence on immune function. Lately an increased interest in n-3 PUFA supplementation has reached the world of sport nutrition, where the majority of athletes rely on nutrition strategies to improve their training and performance. A vast amount of attention is paid in increasing metabolic capacity, delaying the onset of fatigue, and improving muscle hypertrophy and neuromuscular function. Nutritional strategies are also frequently considered for enhancing recovery, improving immune function and decreasing oxidative stress. The current review of the literature shows that data regarding the effects of n-3PUFA supplementation are conflicting and we conclude that there is, therefore, not enough evidence supporting a beneficial role on the aforementioned aspects of exercise performance.

Longchain polyunsaturated fatty acid supplementation in preterm infants

BACKGROUND

Controversy exists over whether longchain polyunsaturated fatty acids (LCPUFA) are essential nutrients for preterm infants because they may not be able to synthesise sufficient amounts of LCPUFA to meet the needs of the developing brain and retina.

OBJECTIVES

To assess whether supplementation of formula milk with LCPUFA is safe and of benefit to preterm infants. The main areas of interest were the effects of supplementation on the visual function, development and growth of preterm infants.

SEARCH METHODS

Trials were identified by searching the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 2) in the Cochrane Library (searched 28 February 2016), MEDLINE Ovid (1966 to 28 February 2016), Embase Ovid (1980 to 28 February 2016), CINAHL EBSCO (Cumulative Index to Nursing and Allied Health Literature; 1980 to 28 February 2016), MEDLINE In Process & Other Non-indexed Citations (1966 to 28 February 2016) and by checking reference lists of articles and conference proceedings. We also searched ClinicalTrials.gov (13 April 2016). No language restrictions were applied.

SELECTION CRITERIA

All randomised trials evaluating the effect of LCPUFA-supplemented formula in enterally-fed preterm infants (compared with standard formula) on visual development, neurodevelopment and physical growth. Trials reporting only biochemical outcomes were not included.

DATA COLLECTION AND ANALYSIS

All authors assessed eligibility and trial quality, two authors extracted data separately. Study authors were contacted for additional information.

MAIN RESULTS

Seventeen trials involving 2260 preterm infants were included in the review. The risk of bias varied across the included trials with 10 studies having low risk of bias in a majority of the domains. The median gestational age (GA) in the included trials was 30 weeks and median birth weight (BW) was 1300 g. The median concentration of docosahexaenoic acid (DHA) was 0.33% (range: 0.15% to 1%) and arachidonic acid (AA) 0.37% (range: 0.02% to 0.84%). Visual acuity Visual acuity over the first year was measured by Teller or Lea acuity cards in eight studies, by visual evoked potential (VEP) in six studies and by electroretinogram (ERG) in two studies. Most studies found no significant differences in visual acuity between supplemented and control infants. The form of data presentation and the varying assessment methods precluded the use of meta-analysis. A GRADE analysis for this outcome indicated that the overall quality of evidence was low. Neurodevelopment Three out of seven studies reported some benefit of LCPUFA on neurodevelopment at different postnatal ages. Meta-analysis of four studies evaluating Bayley Scales of Infant Development at 12 months (N = 364) showed no significant effect of supplementation (Mental Development Index (MDI): MD 0.96, 95% CI -1.42 to 3.34; P = 0.43; I² = 71% - Psychomotor DeveIopment Index (PDI): MD 0.23, 95% CI -2.77 to 3.22; P = 0.88; I² = 81%). Furthermore, three studies at 18 months (N = 494) also revealed no significant effect of LCPUFA on neurodevelopment (MDI: MD 2.40, 95% CI -0.33 to 5.12; P = 0.08; I² = 0% - PDI: MD 0.74, 95% CI -1.90 to 3.37; P = 0.58; I² = 54%). A GRADE analysis for these outcomes indicated that the overall quality of evidence was low. Physical growth Four out of 15 studies reported benefits of LCPUFA on growth of supplemented infants at different postmenstrual ages (PMAs), whereas two trials suggested that LCPUFA-supplemented infants grow less well. One trial reported mild reductions in length and weight z scores at 18 months. Meta-analysis of five studies (N = 297) showed increased weight and length at two months post-term in supplemented infants (Weight: MD 0.21, 95% CI 0.08 to 0.33; P = 0.0010; I² = 69% - Length: MD 0.47, 95% CI 0.00 to 0.94; P = 0.05; I² = 0%). Meta-analysis of four studies at a corrected age of 12 months (N = 271) showed no significant effect of supplementation on growth outcomes (Weight: MD -0.10, 95% CI -0.31 to 0.12; P = 0.34; I² = 65% - Length: MD 0.25; 95% CI -0.33 to 0.84; P = 0.40; I² = 71% - Head circumference: MD -0.15, 95% CI -0.53 to 0.23; P = 0.45; I² = 0%). No significant effect of LCPUFA on weight, length or head circumference was observed on meta-analysis of two studies (n = 396 infants) at 18 months (Weight: MD -0.14, 95% CI -0.39 to 0.10; P = 0.26; I² = 66% - Length: MD -0.28, 95% CI -0.91 to 0.35; P = 0.38; I² = 90% - Head circumference: MD -0.18, 95% CI -0.53 to 0.18; P = 0.32; I² = 0%). A GRADE analysis for this outcome indicated that the overall quality of evidence was low.

AUTHORS' CONCLUSIONS

Infants enrolled in the trials were relatively mature and healthy preterm infants. Assessment schedule and methodology, dose and source of supplementation and fatty acid composition of the control formula varied between trials. On pooling of results, no clear long-term benefits or harms were demonstrated for preterm infants receiving LCPUFA-supplemented formula.

Polyunsaturated fatty acid supplementation in infancy for the prevention of allergy

BACKGROUND

Early dietary intakes may influence the development of allergic disease. It is important to determine if dietary polyunsaturated fatty acids (PUFAs) given as supplements or added to infant formula prevent the development of allergy.

OBJECTIVES

To determine the effect of higher PUFA intake during infancy to prevent allergic disease.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review group to search the Cochrane Central Register of Controlled Trials (CENTRAL 2015, Issue 9), MEDLINE (1966 to 14 September 2015), EMBASE (1980 to 14 September 2015) and CINAHL (1982 to 14 September 2015). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials that compared the use of a PUFA with no PUFA in infants for the prevention of allergy.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed trial quality and extracted data from the included studies. We used fixed-effect analyses. The treatment effects were expressed as risk ratio (RR) with 95% confidence intervals (CI). We used the GRADE approach to assess the quality of evidence.

MAIN RESULTS

The search found 17 studies that assessed the effect of higher versus lower intake of PUFAs on allergic outcomes in infants. Only nine studies enrolling 2704 infants reported allergy outcomes that could be used in meta-analyses. Of these, there were methodological concerns for eight.In infants up to two years of age, meta-analyses found no difference in incidence of all allergy (1 study, 323 infants; RR 0.96, 95% CI 0.73 to 1.26; risk difference (RD) -0.02, 95% CI -0.12 to 0.09; heterogeneity not applicable), asthma (3 studies, 1162 infants; RR 1.04, 95% CI 0.80 to 1.35, I2 = 0%; RD 0.01, 95% CI -0.04 to 0.05, I2 = 0%), dermatitis/eczema (7 studies, 1906 infants; RR 0.93, 95% CI 0.82 to 1.06, I2 = 0%; RD -0.02, 95% CI -0.06 to 0.02, I2 = 0%) or food allergy (3 studies, 915 infants; RR 0.81, 95% CI 0.56 to 1.19, I2 = 63%; RD -0.02, 95% CI -0.06 to 0.02, I2 = 74%). There was a reduction in allergic rhinitis (2 studies, 594 infants; RR 0.47, 95% CI 0.23 to 0.96, I2 = 6%; RD -0.04, 95% CI -0.08 to -0.00, I2 = 54%; number needed to treat for an additional beneficial outcome (NNTB) 25, 95% CI 13 to ∞).In children aged two to five years, meta-analysis found no difference in incidence of all allergic disease (2 studies, 154 infants; RR 0.69, 95% CI 0.47 to 1.02, I2 = 43%; RD -0.16, 95% CI -0.31 to -0.00, I2 = 63%; NNTB 6, 95% CI 3 to ∞), asthma (1 study, 89 infants; RR 0.45, 95% CI 0.20 to 1.02; RD -0.20, 95% CI -0.37 to -0.02; heterogeneity not applicable; NNTB 5, 95% CI 3 to 50), dermatitis/eczema (2 studies, 154 infants; RR 0.65, 95% CI 0.34 to 1.24, I2 = 0%; RD -0.09 95% CI -0.22 to 0.04, I2 = 24%) or food allergy (1 study, 65 infants; RR 2.27, 95% CI 0.25 to 20.68; RD 0.05, 95% CI -0.07 to 0.16; heterogeneity not applicable).In children aged two to five years, meta-analysis found no difference in prevalence of all allergic disease (2 studies, 633 infants; RR 0.98, 95% CI 0.81 to 1.19, I2 = 36%; RD -0.01, 95% CI -0.08 to 0.07, I2 = 0%), asthma (2 studies, 635 infants; RR 1.12, 95% CI 0.82 to 1.53, I2 = 0%; RD 0.02, 95% CI -0.04 to 0.09, I2 = 0%), dermatitis/eczema (2 studies, 635 infants; RR 0.81, 95% CI 0.59 to 1.09, I2 = 0%; RD -0.04 95% CI -0.11 to 0.02, I2 = 0%), allergic rhinitis (2 studies, 635 infants; RR 1.02, 95% CI 0.83 to 1.25, I2 = 0%; RD 0.01, 95% CI -0.06 to 0.08, I2 = 0%) or food allergy (1 study, 119 infants; RR 0.27, 95% CI 0.06 to 1.19; RD -0.10, 95% CI -0.20 to -0.00; heterogeneity not applicable; NNTB 10, 95% CI 5 to ∞).

AUTHORS' CONCLUSIONS

There is no evidence that PUFA supplementation in infancy has an effect on infant or childhood allergy, asthma, dermatitis/eczema or food allergy. However, the quality of evidence was very low. There was insufficient evidence to determine an effect on allergic rhinitis.

Fatty acid composition in breastfeeding and school performance in children aged 12 years

PURPOSE

Breastfeeding has been associated with improved cognition. It remains unclear whether long-chain polyunsaturated fatty acids (LC-PUFAs) play a role in this association. We assessed the association between LC-PUFA concentrations in infant feeding and school performance at age 12.

METHODS

Within a population-based birth cohort, we compared school performance of 277 non-breastfed children and 157 children who had fatty acid composition of their mothers' breast milk measured. Two indicators of school performance were: (1) the score on a standardized achievement test and (2) the teacher's advice regarding a child's potential performance level in secondary education. Linear regression and multinomial logistic regression analyses were performed to assess the independent association between LC-PUFA content of breast milk and school performance.

RESULTS

Girls, who received breast milk with a relative high content (above the median) of docosahexaenoic acid (DHA), had a higher Cito-test score (β = 2.96 points, 95 % CI 0.24; 5.69) than non-breastfed girls. Among the breastfed girls, each percentage point of higher content of total n-3 LC-PUFA (β = 4.55, 95 % CI 0.43; 8.66) and DHA (β = 7.09, 95 % CI 0.9; 13.3) was associated with a higher Cito-test score. The association between LC-PUFA content and teacher school advice showed a similar pattern. There was no association between LC-PUFA content and school performance in boys.

CONCLUSION

Although a large part of the association between infant milk feeding and cognition seems to be explained by sociodemographic and lifestyle-related factors, a relative high content of n-3 PUFAs, especially DHA, in breast milk is associated with better school performance in 12-year-old girls but not in boys.

The Effect of Supplementation of Long-Chain Polyunsaturated Fatty Acids During Lactation on Neurodevelopmental Outcomes of Preterm Infant From Infancy to School Age: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVE

Long-chain polyunsaturated fatty acids, especially docosahexaenoic acid, have been suggested as a nutrition factor affecting visual and neurobehavioral development of preterm infants. Several randomized controlled trials (RCTs) have investigated the effect of supplementation of long-chain polyunsaturated fatty acids on preterm infants. We conducted a systematic review and meta-analysis to examine the efficacy of long-chain polyunsaturated fatty acid supplementation of formula or breast milk on the neurodevelopment outcomes of preterm infants.

METHODS

Two authors searched PubMed and Cochrane Library (CENTRAL) for RCTs assessing efficacy of long-chain polyunsaturated fatty acids supplementation on the neurobehavioral and development outcomes of preterm infant. Human RCTs which supplemented long-chain polyunsaturated fatty acids during lactation and assessed neurodevelopment were included. The quality of each RCT was assessed, and the results of eligible trials were included in the systematic review and meta-analysis.

RESULTS

We included 11 RCTs with 2272 total participants. Methodologic limitations existed to some extent in most RCTs that were included. Because the age of the participants from different trails was not the same, different scales and indexes had been assessed from different RCTs. Our meta-analysis indicated a significant effect of long-chain polyunsaturated fatty acids supplementation on the neurodevelopment of preterm infants assessed by the Mental Development Index of the Bayley Scales at one to three years of age versus the control groups.

CONCLUSION

Analysis of our consolidated data indicates that long-chain fatty acid supplementation results in a significant improvement in the neurodevelopment of preterm infants as assessed by the Mental Development Index at one to three years of age. The available evidence suggests that long-chain polyunsaturated fatty acid supplementation during lactation may accelerate the pace of neurodevelopment in preterm infants, although their final developmental outcome may be unchanged.

Diffusion tensor imaging and behavior in premature infants at 8 years of age, a randomized controlled trial with long-chain polyunsaturated fatty acids

BACKGROUND

Very low birth weight (VLBW, birth weight<1500 g) children have increased risk of behavioral problems. Diffusion tensor imaging (DTI) of the brain shows reduced white matter maturation. Long-chain polyunsaturated fatty acids are hypothesized to improve both myelination and behavioral outcome.

AIMS

To test the hypothesis that postnatal supplementation with docosahexaenoic acid (DHA) and arachidonic acid (AA) to very low birth weight infants would influence cerebral white matter measured by DTI and improve behavioral outcome at 8 years of age.

STUDY DESIGN

Eight-year follow-up of a randomized, double-blinded, placebo-controlled study of postnatal supplementation with DHA and AA to 129 VLBW infants fed human milk.

SUBJECTS

Ninety-eight children (76%) met for follow-up at 8 years.

OUTCOME MEASURES

Cerebral white matter measured by DTI. Behavioral outcome measured by Strengths and Difficulties questionnaire and selected scales from the Child Behavior Checklist.

RESULTS

No significant differences between the intervention group and the control group were found on white matter microstructure or behavioral data. A non-significant finding of higher fractional anisotropy (FA) in a cluster in the corpus callosum of the intervention group is discussed.

CONCLUSIONS

The present study is the first long-term follow-up of a randomized controlled trial with DHA and AA to human milk fed VLBW infants exploring cerebral white matter microstructure measured by DTI and parent-reported behavioral problems. No effects on white matter microstructure or behavioral outcome were observed at 8 years of age.

Infant formula and neurocognitive outcomes: impact of study end-point selection

OBJECTIVES

Assessing validity and reliability of end points used in docosahexanoic and arachidonic acids (DHA and ARA) infant formula supplementation trials as an example for addressing the impact of end-point selection and critical need for well-defined, reliable and validated clinical outcome assessments for neurocognitive assessment in neonates and infants.

STUDY DESIGN

We searched eight electronic databases and reviewed all randomized, controlled human trials using DHA/ARA supplements with neurodevelopment clinical outcomes. We systematically evaluated the validity and reliability of end-point measures based on the criteria for studying nutritional additives recommended by the Institute of Medicine, criteria described in the Food and Drug Administration guidance for clinical outcome assessment, development and literature review.

RESULTS

We identified 29 articles that met the selection criteria. The end points that were used for neurodevelopment measures in 23 out of 29 original short-term studies included the Bayley Scale of Infant Development (BSID)-I and -II (n=12), Brunet-Lezine test (n=2), videotape infant's movements (n=1), record time to milestones including sitting, crawling, standing and walking (n=1), problem-solving test (n=2), brainstem auditory-evoked potential (n=1), Touwen examination (n=1), Fagan test of infant intelligence (n=2) and visual habituation protocol (n=1). None of these end points have a long-term predictive property for neurocognitive assessment. Compared with standard infant formula, the beneficial effects of DHA/ARA supplementation on neurodevelopment were reported in 2 out of 12 studies using BSID vs 8 out of 11 studies using other end-point measures. In addition, 6 out of 29 long-term follow-up studies used the end points including Stanford-Binet IQ test (n=1), Wechsler Preschool and Primary Scale of Intelligence (n=4) and Bracken Basic Concept Scale (n=1), which are generally scales of intellectual ability and typically do not change substantively in the short term. None of these long-term follow-up studies demonstrated beneficial effects of DHA/ARA supplementation on neurodevelopment.

CONCLUSION

The choice of end-point measures affects the outcomes of DHA/ARA-supplemented infant formula trials. Available data are currently inadequate to conclude that DHA/ARA supplementation has a clinically meaningful beneficial effect upon neurological development. Although BSID is validated to assess early developmental delays, it is not designed to predict long-term neurocognitive outcome. A well-defined, valid and reliable clinical outcome assessment that measures neurocognitive function in neonates and infants is essential to provide the scientific evidence required for future clinical trials.

Long-chain polyunsaturated fatty acids and cognition in VLBW infants at 8 years: an RCT

OBJECTIVE

To test the hypothesis that supplementation with the long chain polyunsaturated fatty acids docosahexaenoic acid (DHA) and arachidonic acid (AA) to very low birth weight (VLBW) infants would improve long-term cognitive functions and influence neuroanatomical volumes and cerebral cortex measured by MRI.

METHODS

The current study is a follow-up of a randomized, double-blinded, placebo-controlled study of supplementation with high-dose DHA (0.86%) and AA (0.91%) to 129 VLBW infants fed human milk. Ninety-eight children participated at 8 years follow-up and completed a broad battery of cognitive tests. Eighty-one children had cerebral MRI scans of acceptable quality.

RESULTS

There were no significant differences between the intervention group and the control group on any of the cognitive measures. Equally, MRI data on segmental brain volumes and cerebral cortex volume, area, and thickness suggested no overall group effect.

CONCLUSIONS

This study is the first long-term follow-up of a randomized controlled trial with supplementation of DHA and AA to human milk fed VLBW infants investigating both cognitive functions and brain macrostructure measured by MRI. No cognitive or neuroanatomical effects of the supplementation were detected at 8 years of age.

Neurodevelopmental outcomes at 7 years' corrected age in preterm infants who were fed high-dose docosahexaenoic acid to term equivalent: a follow-up of a randomised controlled trial

OBJECTIVE

To determine if improvements in cognitive outcome detected at 18 months' corrected age (CA) in infants born <33 weeks' gestation receiving a high-docosahexaenoic acid (DHA) compared with standard-DHA diet were sustained in early childhood.

DESIGN

Follow-up of a multicentre randomised controlled trial. Randomisation was stratified for sex, birth weight (<1250 vs ≥1250 g) and hospital.

SETTING

Five Australian tertiary hospitals from 2008 to 2013.

PARTICIPANTS

626 of the 657 participants randomised between 2001 and 2005 were eligible to participate.

INTERVENTIONS

High-DHA (≈1% total fatty acids) enteral feeds compared with standard-DHA (≈0.3% total fatty acids) from age 2-4 days until term CA.

PRIMARY OUTCOME

Full Scale IQ of the Wechsler Abbreviated Scale of Intelligence (WASI) at 7 years CA. Prespecified subgroup analyses based on the randomisation strata (sex, birth weight) were conducted.

RESULTS

604 (92% of the 657 originally randomised) consented to participate (291 high-DHA, 313 standard-DHA). To address missing data in the 604 consenting participants (22 for primary outcome), multiple imputation was performed. The Full Scale IQ was not significantly different between groups (high-DHA 98.3, SD 14.0, standard-DHA 98.5, SD 14.9; mean difference adjusted for sex, birthweight strata and hospital -0.3, 95% CI -2.9 to 2.2; p=0.79). There were no significant differences in any secondary outcomes. In prespecified subgroup analyses, there was a significant sex by treatment interaction on measures of parent-reported executive function and behaviour. Scores were within the normal range but girls receiving the high-DHA diet scored significantly higher (poorer outcome) compared with girls receiving the standard-DHA diet.

CONCLUSIONS

Supplementing the diets of preterm infants with a DHA dose of approximately 1% total fatty acids from days 2-4 until term CA showed no evidence of benefit at 7 years' CA.

TRIAL REGISTRATION NUMBER

Australian New Zealand Clinical Trials Registry: ACTRN12606000327583.

Beyond building better brains: bridging the docosahexaenoic acid (DHA) gap of prematurity

Long-chain polyunsaturated fatty acids (LCPUFA) including docosahexaenoic acid (DHA) are essential for normal vision and neurodevelopment. DHA accretion in utero occurs primarily in the last trimester of pregnancy to support rapid growth and brain development. Premature infants, born before this process is complete, are relatively deficient in this essential fatty acid. Very low birth weight (VLBW) infants remain deficient for a long period of time due to ineffective conversion from precursor fatty acids, lower fat stores and a limited nutritional provision of DHA after birth. In addition to long-term visual and neurodevelopmental risks, VLBW infants have significant morbidity and mortality from diseases specific to premature birth, including bronchopulmonary dysplasia, necrotizing enterocolitis, and retinopathy of prematurity. There is increasing evidence that DHA has protective benefits against these disease states. The aim of this article is to identify the unique needs of premature infants, review the current recommendations for LCPUFA provision in infants and discuss the caveats and innovative new ways to overcome the DHA deficiency through postnatal supplementation, with the long-term goal of improving morbidity and mortality in this at-risk population.

Current information and Asian perspectives on long-chain polyunsaturated fatty acids in pregnancy, lactation, and infancy: systematic review and practice recommendations from an early nutrition academy workshop

The Early Nutrition Academy supported a systematic review of human studies on the roles of pre- and postnatal long-chain polyunsaturated fatty acids (LC-PUFA) published from 2008 to 2013 and an expert workshop that reviewed the information and developed recommendations, considering particularly Asian populations. An increased supply of n-3 LC-PUFA during pregnancy reduces the risk of preterm birth before 34 weeks of gestation. Pregnant women should achieve an additional supply ≥200 mg docosahexaenic acid (DHA)/day, usually achieving a total intake ≥300 mg DHA/day. Higher intakes (600-800 mg DHA/day) may provide greater protection against early preterm birth. Some studies indicate beneficial effects of pre- and postnatal DHA supply on child neurodevelopment and allergy risk. Breast-feeding is the best choice for infants. Breast-feeding women should get ≥200 mg DHA/day to achieve a human milk DHA content of ∼0.3% fatty acids. Infant formula for term infants should contain DHA and arachidonic acid (AA) to provide 100 mg DHA/day and 140 mg AA/day. A supply of 100 mg DHA/day should continue during the second half of infancy. We do not provide quantitative advice on AA levels in follow-on formula fed after the introduction of complimentary feeding due to a lack of sufficient data and considerable variation in the AA amounts provided by complimentary foods. Reasonable intakes for very-low-birth weight infants are 18-60 mg/kg/day DHA and 18-45 mg/kg/day AA, while higher intakes (55-60 mg/kg/day DHA, ∼1% fatty acids; 35-45 mg/kg/day AA, ∼0.6-0.75%) appear preferable. Research on the requirements and effects of LC-PUFA during pregnancy, lactation, and early childhood should continue. © 2014 S. Karger AG, Basel.

LCPUFAs as conditionally essential nutrients for very low birth weight and low birth weight infants: metabolic, functional, and clinical outcomes-how much is enough?

Preterm infants are denied the rapid accumulation of docosahexaenoic acid (DHA) occurring during the third trimester in utero. The potential benefit of long-chain polyunsaturated fatty acids (LCPUFAs) has generated interest over the last 3 decades. Early intervention trials assessed the effects of supplementing infant formulas lacking DHA with concentrations equivalent to LCPUFA in milk of women from Westernized societies, leading to the inclusion of LCPUFA by the year 2000. Recently attention has been on determining the optimal dose of DHA and on whether there is in advantage in matching the higher doses of late pregnancy.

Long-term effects of LCPUFA supplementation on childhood cognitive outcomes

BACKGROUND

The effect of long-chain polyunsaturated fatty acid (LCPUFA) intake on cognitive development is controversial. Most randomized trials have assessed cognition at 18 mo, although significant development of cognitive abilities (early executive function) emerge later.

OBJECTIVE

The objective was to evaluate cognition beyond 18 mo and longitudinal cognitive change from 18 mo to 6 y in children who were fed variable amounts of docosahexaenoic acid (0.32%, 0.64%, and 0.96% of total fatty acids) and arachidonic acid (ARA; 0.64%) compared with children who were not fed LCPUFA as infants.

DESIGN

Eighty-one children (19 placebo, 62 LCPUFA) who participated in a double-blind, randomized trial of LCPUFA supplementation as infants were re-enrolled at 18 mo and tested every 6 mo until 6 y on age-appropriate standardized and specific cognitive tests.

RESULTS

LCPUFA supplementation did not influence performance on standardized tests of language and performance at 18 mo; however, significant positive effects were observed from 3 to 5 y on rule-learning and inhibition tasks, the Peabody Picture Vocabulary Test at 5 y, and the Weschler Primary Preschool Scales of Intelligence at 6 y. Effects of LCPUFAs were not found on tasks of spatial memory, simple inhibition, or advanced problem solving.

CONCLUSIONS

The data from this relatively small trial suggest that, although the effects of LCPUFAs may not always be evident on standardized developmental tasks at 18 mo, significant effects may emerge later on more specific or fine-grained tasks. The results imply that studies of nutrition and cognitive development should be powered to continue through early childhood. This parent trial was registered at clinicaltrials.gov as NCT00266825.

Effects of long-chain PUFA supplementation in infant formula on cognitive function in later childhood

BACKGROUND

Evidence is accumulating that a dietary supply of long-chain polyunsaturated fatty acids (LC-PUFAs) enhances the development of attention and efficient information processing in infants. However, it is uncertain whether LC-PUFAs in infancy influence cognitive development in later childhood.

OBJECTIVE

The objective was to determine the effects of dietary LC-PUFAs in infancy on measures of cognitive function at age 6 y.

DESIGN

Infants were randomly assigned to receive formula containing either docosahexaenoic acid and arachidonic acid or no LCPUFAs for a period of 4 mo. A reference breastfed group was also included. In a follow-up conducted at age 6 y, children received assessments of intelligence quotient (IQ), attention control (Day-Night Test), and speed of processing on the Matching Familiar Figures Test (MFFT).

RESULTS

At follow-up there were 71 children in the LC-PUFA group, 76 in the control group, and 88 in the breastfed group. The formula groups did not differ on measures of Full-Scale IQ (LCPUFA mean = 98.0; control mean = 100.9) or attention control (LCPUFA mean = 12.7; control mean = 12.8). MFFT error scores were the same for both formula groups, but when making correct responses, the LC-PUFA group was significantly faster (mean = 6.2 s) than the control group [mean = 7.8 s; F(1, 131) = 6.09, P = 0.015].

CONCLUSIONS

IQ scores of children who were fed a formula containing either LC-PUFAs or no LC-PUFAs did not differ at age 6 y. However, children who received LC-PUFAs were faster at processing information compared with children who received unsupplemented formula. Variation in the dietary supply of LC-PUFAs in the first months of life may have long-term consequences for the development of some cognitive functions in later childhood.