Achieving definitive results in long-chain polyunsaturated fatty acid supplementation trials of term infants: factors for consideration

Supplementation with oil rich in eicosapentaenoic acid, but not in docosahexaenoic acid, improves global cognitive function in healthy, young adults: results from randomized controlled trials

BACKGROUND

Evidence regarding the effects of the omega-3 (ɷ-3) PUFAs (n-3 PUFAs) DHA and EPA on cognition is lacking.

OBJECTIVES

We investigated whether supplementation with oils rich in EPA or DHA improves cognition, prefrontal cortex (PFC) hemoglobin (Hb) oxygenation, and memory consolidation.

METHODS

Healthy adults (n = 310; age range: 25-49 y) completed a 26-wk randomized controlled trial in which they consumed either 900 mg DHA/d and 270 mg EPA/d (DHA-rich oil), 360 mg DHA/d and 900 mg EPA/d (EPA-rich oil), or 3000 mg/d refined olive oil (placebo). Cognitive performance and memory consolidation were assessed via computerized cognitive test battery. PFC Hb oxygenation was measured using near infrared spectroscopy (NIRS).

RESULTS

Both global accuracy and speed improved with EPA-rich oil compared with placebo and DHA-rich oil [EPA vs. placebo accuracy: estimated marginal mean (EMM) = 0.17 (95% CI: 0.09, 0.24) vs. EMM = 0.03 (95% CI = -0.04, 0.11); P = 0.044; EPA vs. placebo speed: EMM = -0.15 (95% CI: -0.22, -0.07) vs. EMM = 0.03 (95% CI: -0.05, 0.10); P = 0.003]. Accuracy of memory was improved with EPA compared with DHA [EMM = 0.66 (95% CI: 0.26, 1.06) vs. EMM = -0.08 (95% CI: -0.49, 0.33); P = 0.034]. Both EPA- and DHA-rich oils showed trends towards reduced PFC oxygenated Hb (oxy-Hb) compared with placebo [placebo: EMM = 27.36 µM (95% CI: 25.73, 28.98); DHA: EMM = 24.62 µM (95% CI: 22.75, 26.48); P = 0.060; EPA: EMM = 24.97 µM (95% CI: 23.35, 26.59); P = 0.082].

CONCLUSIONS

EPA supplementation improved global cognitive function and was superior to the oil enriched with DHA. Interpreted within a neural efficiency framework, reduced PFC oxygenated Hb suggests that n-3 PUFAs may be associated with increased efficiency.These trials were registered in the clinical trials registry (https://clinicaltrials.gov/) as NCT03158545, NCT03592251, NCT02763514.

ARA or no ARA in infant formulae, that is the question

Recently, the European Commission issued a Delegated Regulation updating the compositional and information requirements for infant and follow-on formulae that are to be applied at the latest in February 2021. This new regulation changes the status of docosahexaenoic acid (DHA) from an optional ingredient to a mandatory nutrient in these formulae at levels between 20 and 50mg/100kcal (0.5-1% of fatty acids). By contrast, arachidonic acid (ARA) becomes an optional nutrient. Following publication of the new regulation, global scientific experts have expressed concerns regarding the potential health risks of new infant formulae containing only DHA, especially at levels higher than those in breast milk and infant formulae marketed to date. Both DHA and ARA play a crucial role in infant development. First, breast milk, the gold standard for infant feeding, contains both DHA and ARA. Second, during development, the conversion of linoleic acid into ARA through desaturation steps is not sufficient to meet nutritional needs, especially in carriers of newly identified genetic variants in fatty acid desaturases, which weaken the biosynthetic production of ARA. Third, circulating levels of DHA and ARA in breastfed infants can only be matched with the addition of both fatty acids to formulae. And fourth, most studies performed to date have demonstrated that important physiological and developmental endpoints are sensitive to the ratio of dietary ARA:DHA. The precautionary principle applies when implementing the new EU regulation for infant and follow-on formulae. As a consequence, given the vulnerability of developing infants as well as the absence of conclusive evidence that formulae with at least 20mg DHA/100kcal, but no ARA, are safe and suitable to support the growth and development of infants similar to their breastfed peers, it remains necessary to still market formulas containing both ARA and DHA until proved otherwise.

Diurnal rhythm of plasma EPA and DHA in healthy adults

Knowledge of the diurnal variation in circulating omega-3 polyunsaturated fatty acids (n-3 PUFAs) may be an important consideration for the development of dosing protocols designed to optimise tissue delivery of these fatty acids. The objective of the current study was to examine the variation in plasma concentrations of eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) over a 24-h period in healthy adults under eating and sleeping conditions generally approximate to a free-living environment. Twenty-one healthy participants aged 25-44 years took part in a single laboratory visit encompassing an overnight stay. EPA and DHA were measured in plasma samples collected every two hours from 22:00 until 22:00 the following day, with all meals being provided at conventional times. Cosinor analysis was used to estimate the diurnal variation in each fatty acid from pooled data across all participants. A significant diurnal variation in the pooled plasma concentrations of both fatty acids was detected. However, evidence of distinct rhythmicity was strongest for DHA. The timing of the peak concentration of DHA was 17:43 with a corresponding nadir at 05:43. In comparison, the observed acrophase for EPA was delayed by three hours, occurring at 20:41, with a nadir at 08:41. This is the first time that the diurnal variation in these important bioactive fatty acids has been described in a sample of healthy adults following a normal pattern of eating and sleeping. In the absence of any dietary intake of EPA and DHA, circulating levels of these fatty acids fall during the overnight period and reach their lowest point in the morning. Consumption of n-3 PUFAs at night time, which counteracts this pattern, may have functional significance.

Docosahexaenoic and Arachidonic Acid Supplementation of Toddlers Born Preterm Does Not Affect Short-Term Growth or Adiposity

BACKGROUND

Dietary DHA intake among US toddlers is low. Healthy physical growth is an important objective for the clinical care of children born preterm.

OBJECTIVES

The aim of the trial was to examine the effects of supplementing toddlers born preterm with DHA and arachidonic acid (AA) for 180 d on growth and adiposity.

METHODS

Omega Tots, a randomized placebo-controlled trial, was conducted between April 2012 and March 2017. Children born at <35 wk gestation who were 10-16 mo in corrected age were assigned to receive daily oral supplements of DHA and AA (200 mg each, "DHA + AA") or corn oil (placebo) for 180 d. Prespecified secondary outcomes included weight, length, head circumference, mid-upper arm circumference, triceps and subscapular skinfolds, BMI, and their respective z scores, and body fat percentage, which were measured at baseline and trial completion. Mixed-effects regression was used to compare the change in outcomes between the DHA + AA and placebo groups, controlling for baseline values.

RESULTS

Among 377 children included in the analysis (median corrected age = 15.7 mo, 48.3% female), 348 (92.3%) had growth or adiposity data at baseline and trial end. No statistically significant differences between the DHA + AA and placebo groups in growth or adiposity outcomes were observed. For instance, the change in weight-for-age z scores was 0.1 for the DHA + AA group and 0.0 for the placebo group (effect size = 0.01, P = 0.99). However, post-hoc subgroup analyses revealed a statistically significant interaction between treatment group and sex, suggesting somewhat slower linear growth for females assigned to the DHA + AA group compared with the placebo group.

CONCLUSIONS

Among toddlers born preterm, daily supplementation with DHA + AA for 180 d resulted in no short-term differences in growth or adiposity compared with placebo. If DHA supplementation is implemented after the first year of life, it can be expected to have no effect on short-term growth or adiposity. This trial is registered with clinicaltrials.gov as NCT02199808.

Effects of LC-PUFA supply via complementary food on infant development-a food based intervention (RCT) embedded in a total diet concept

BACKGROUND

With the introduction of complementary food, long-chain PUFA (LC-PUFA) supply usually decreases during the second 6 months of life. However, the need for LC-PUFA is still high for infant's rapid development. The aim of this randomized, controlled intervention trial was to examine the effects of an increased n-3 (LC-)PUFA supply using alternative complementary foods on infants' visual and cognitive development.

METHODS

Mother-child dyads of term infants were recruited in maternity hospitals and randomly assigned to one of three study groups, which all were fed according to the German dietary schedule for infant nutrition. Intervention group IG-R (n = 54) received jars of complementary food with rapeseed oil, IG-F (n = 48) jars with oily fish twice a week and the control group (CG, n = 58) the same jars as IG-R with corn oil instead of rapeseed oil during the intervention period (5th-10th month of age). The outcome measures were latencies of FVEP, Bayley's mental developmental index (MDI), and psychomotor developmental index (PDI).

RESULTS

At 10 months of age, there were no significant differences in latencies of FVEP, Bayley's MDI, or in PDI index between the intervention and control groups.

CONCLUSIONS

Fish and rapeseed oil used as (LC-)PUFA sources provided with complementary feeding embedded in a structured infant diet did not affect visual or cognitive development of term infants.

Neither n-3 Long-Chain PUFA Supplementation of Mothers through Lactation nor of Offspring in a Complementary Food Affects Child Overall or Social-Emotional Development: A 2 × 2 Factorial Randomized Controlled Trial in Rural Ethiopia

BACKGROUND

The n-3 (ω-3) long-chain polyunsaturated fatty acid (LC-PUFA) docosahexaenoic acid (DHA) is essential for optimal brain development. There is a lack of evidence on the effect of postnatal n-3 LC-PUFA supplementation on child development in low-income countries.

OBJECTIVE

We evaluated the efficacy of fish-oil supplementation through lactation or complementary food supplementation on the development of children aged 6-24 mo in rural Ethiopia.

METHODS

We conducted a double-blind randomized controlled trial of n-3 LC-PUFA supplementation for 12 mo using fish-oil capsules [maternal intervention: 215 mg DHA + 285 mg eicosapentaenoic acid (EPA)] or a fish-oil-enriched complementary food supplement (child intervention: 169 mg DHA + 331 mg EPA). In total, 360 pairs of mothers and infants aged 6-12 mo were randomly assigned to 4 arms: maternal intervention and child control, child intervention and maternal control, maternal and child intervention, and maternal and child control. Primary outcomes were overall developmental performance with the use of a culturally adapted Denver II test that assesses personal-social, language, fine-motor, and gross-motor domains and social-emotional developmental performance using the Ages and Stages Questionnaire: Social Emotional at baseline and at 6 and 12 mo. We used mixed-effects models to estimate intervention effects on developmental performance over time (intervention × time interaction).

RESULTS

The evolution in overall and social-emotional developmental performance over time did not differ across study arms (intervention × time: F = 1.09, P = 0.35, and F = 0.61, P = 0.61, respectively). Effects did not change after adjustment for child age, birth order, and nutritional status; maternal age and education; wealth; family size; and breastfeeding frequency. Children's developmental performance significantly decreased during study follow-up (β: -0.03 SDs/mo; 95% CI: -0.04, -0.01 SD/mo; P < 0.01).

CONCLUSIONS

n-3 LC-PUFA supplementation does not affect overall or social-emotional development of children aged 6-24 mo in a low-income setting. Follow-up of the cohort is recommended to determine whether there are long-term effects of the intervention. This trial was registered at clinicaltrials.gov as NCT01817634.

Polyunsaturated fatty acids and child neurodevelopment among a population exposed to DDT: a cohort study

BACKGROUND

Child neurodevelopment has been positively linked to maternal intake of polyunsaturated fatty acids (PUFAs) during pregnancy; however, it is unknown if that relationship persists among populations exposed to environmental neurotoxicants.

OBJECTIVE

The aim of this work was to assess whether maternal dietary intake of PUFAs during pregnancy is positively associated with child neurodevelopment, whose mothers were environmentally exposed to 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT).

METHODS

A prospective cohort study with 276 mother-child pairs was performed in Mexico. Neurodevelopment was assessed by Bayley Scales II from children age 1 to 30 months. Dietary PUFAs intake was estimated by Food Frequency Questionnaire at 1st and 3rd trimester of pregnancy. DDE (1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene, the main metabolite of DDT) maternal serum levels were determined by electron capture gas chromatography. Longitudinal multivariate linear mixed-effects analysis, which combines mental (MDI) and motor (PDI) Bayley scales in a single model, were performed.

RESULTS

Our results show that in a sample environmentally exposed to DDT, maternal ingestion of DPA during the first trimester of pregnancy was positively associated with MDI (β = 0.10, 95% CI 0.02, 0.18) in children from 1 to 30 months. Likewise, our results suggest that dietary ALA may be also related to MDI.

CONCLUSION

DPA may benefit neurodevelopment even in populations exposed to DDT. Our results strengthen the importance of PUFAs intake during the prenatal period.

Dietary Docosahexaenoic Acid and Arachidonic Acid in Early Life: What Is the Best Evidence for Policymakers?

BACKGROUND

A wealth of information on the functional roles of docosahexaenoic acid (DHA) and arachidonic acid (ARA) from cellular, animal, and human studies is available. Yet, there remains a lack of cohesion in policymaking for recommended dietary intakes of DHA and ARA in early life. This is predominantly driven by inconsistent findings from a relatively small number of randomised clinical trials (RCTs), which vary in design, methodology, and outcome measures, all of which were conducted in high-income countries. It is proposed that this selective evidence base may not fully represent the biological importance of DHA and ARA during early and later life and the aim of this paper is to consider a more inclusive and pragmatic approach to evidence assessment of DHA and ARA requirements in infants and young children, which will allow policymaking to reflect the marked diversity of need worldwide.

SUMMARY

Data from clinical RCTs is considered in the context of the extensive evidence from experimental, animal and human observational studies. Although the RCT data shows evidence of beneficial effects on visual function and in specific cognitive domains, early methodological approaches do not reflect current thinking and this undermines the strength of evidence. An outline of a framework for an inclusive and pragmatic approach to policy development on dietary DHA and ARA in early life is described.

CONCLUSION

High-quality RCTs that will determine long-term health outcomes in appropriate real-world settings need to be undertaken. In the meantime, a collective pragmatic approach to evidence assessment, may allow public health policymakers to make comprehensive reasoned judgements on the merits, costs, and expediency of dietary DHA and ARA interventions.

Effects of n-3 long-chain PUFA supplementation to lactating mothers and their breastfed children on child growth and morbidity: a 2 × 2 factorial randomized controlled trial in rural Ethiopia

Background

Recurrent infections and inflammation contribute to growth faltering in low-income countries. n-3 (ω-3) Long-chain polyunsaturated fatty-acids (LC-PUFAs) may improve immune maturation, resistance to infections, and growth in young children who are at risk.

Objective

We evaluated the independent and combined effects of fish oil (500 mg n-3 LC-PUFAs/d) supplementation to lactating mothers and their breastfed children, aged 6-24 mo, on child morbidity, systemic inflammation, and growth in southwest Ethiopia.

Design

A 4-arm double-blind randomized controlled trial was conducted by enrolling 360 mother-infant pairs with infants 6-12 mo old. Study arms were both the lactating mother and child receiving fish oil intervention (MCI), only the lactating mother receiving fish oil intervention and child receiving placebo control (MI), only the child receiving intervention and mother receiving placebo control (CI), and both mother and child receiving a placebo supplement or control (C). The primary study outcome was linear growth using monthly changes in length-for-age z score. Anthropometric measurements were taken monthly, and hemoglobin, C-reactive protein, and blood LC-PUFAs were measured at baseline and after 6 and 12 mo of follow-up. Weekly morbidity surveillance was conducted throughout the study.

Results

Fish-oil supplementation significantly increased blood n-3 LC-PUFA concentration (P < 0.01) and decreased the arachidonic acid:(docosahexaenoic acid + eicosapentaenoic acid) ratio (P < 0.001) in all intervention arms. No significant intervention effect was found on linear growth, morbidity, or systemic inflammation. Compared to the control group, a small positive effect on monthly changes in weight-for-length z scores was found in the CI arm (effect size: 0.022/mo; 95% CI: 0.005, 0.039/mo; P = 0.012) and the MCI arm (effect size: 0.018/mo; 95% CI: 0.001, 0.034/mo; P = 0.041).

Conclusions

n-3 LC-PUFA supplementation of lactating mothers and children did not affect child linear growth and morbidity in a low-income setting. n-3 LC-PUFA supplementation given directly to children modestly increased relative weight gain. This trial was registered at clinicaltrials.gov as NCT01817634.

DHA and ARA addition to infant formula: Current status and future research directions

Docosahexaenoic acid (DHA) and arachidonic acid (ARA) are present in breast milk and play important roles in early infant development. A supply of these fatty acids in infant formula (typically following breast milk as a model with ARA > DHA) is thought to be important since endogenous synthesis is insufficient to maintain tissue levels equivalent to breast-fed infants. Intervention studies assessing the impact of DHA- and ARA-supplemented formulas have resulted in numerous positive developmental outcomes (closer to breast-fed infants) including measures of specific cognition functions, visual acuity, and immune responses. A critical analysis of outcome assessment tools reveals the essentiality of selecting appropriate, focused techniques in order to provide accurate evaluation of DHA- and ARA-supplemented formulas. Future research directions should encompass in-depth assessment of specific cognitive outcomes, immune function, and disease incidence, as well as sources of experimental variability such as the status of fatty acid desaturase polymorphisms.

Impact of the n-6:n-3 long-chain PUFA ratio during pregnancy and lactation on offspring neurodevelopment: 5-year follow-up of a randomized controlled trial

BACKGROUND/OBJECTIVES

Evidence regarding the effect of n-3 long-chain polyunsaturated fatty acid (LCPUFA) supplementation during pregnancy on offspring's neurodevelopment is not conclusive.

SUBJECTS/METHODS

In this analysis, the effect of a reduced n-6:n-3 LCPUFA ratio in the diet of pregnant/lactating women (1.2 g n-3 LCPUFA together with an arachidonic acid (AA)-balanced diet between 15th wk of gestation-4 months postpartum vs control diet) on child neurodevelopment at 4 and 5 years of age was assessed. A child development inventory (CDI) questionnaire and a hand movement test measuring mirror movements (MMs) were applied and the association with cord blood LCPUFA concentrations examined.

RESULTS

CDI questionnaire data, which categorizes children as 'normal', 'borderline' or 'delayed' in different areas of development, showed no significant evidence between study groups at 4 (n=119) and 5 years (n=130) except for the area 'letters' at 5 years of age (P=0.043). Similarly, the results did not strongly support the hypothesis that the intervention has a beneficial effect on MMs (for example, at 5 years: dominant hand, fast: adjusted mean difference, -0.08 (-0.43, 0.26); P=0.631). Children exposed to higher cord blood concentrations of docosahexaenoic acid, eicosapentaenoic acid and AA, as well as a lower ratio of n-6:n-3 fatty acids appeared to show beneficial effects on MMs, but these results were largely not statistically significant.

CONCLUSIONS

Our results do not show clear benefits or harms of a change in the n-6:n-3 LCPUFA ratio during pregnancy on offspring's neurodevelopment at preschool age. Findings on cord blood LCPUFAs point to a potential influence on offspring development.

Long chain polyunsaturated fatty acid supplementation in infants born at term

BACKGROUND

The long chain polyunsaturated fatty acids (LCPUFA) docosahexaenoic acid (DHA) and arachidonic acid (AA) are considered essential for maturation of the developing brain, retina and other organs in newborn infants. Standard infant milk formulae are not supplemented with LCPUFA; they contain only alpha-linolenic acid and linoleic acid, from which formula-fed infants must synthesise their own DHA and AA, respectively. Over the past few years, some manufacturers have added LCPUFA to formula milk and have marketed these products as providing an advantage for the overall development of full-term infants.

OBJECTIVES

To assess whether supplementation of formula milk with LCPUFA is both safe and beneficial for full-term infants, while focusing on effects on visual function, neurodevelopment and physical growth.

SEARCH METHODS

Two review authors independently searched the Cochrane Central Register of Controlled Trials (CENTRAL; December 2016), MEDLINE (Ovid, 1966 to December 2016), Embase (Ovid, 1980 to December 2016), the Cumulative Index to Nursing and Allied Health Literature (CINAHL; 1980 to December 2016) and abstracts of the Pediatric Academic Societies (2000 to 2016). We applied no language restrictions.

SELECTION CRITERIA

We reviewed all randomised controlled trials (RCTs) evaluating effects of LCPUFA supplemented versus non-supplemented formula milk on visual function, neurodevelopment and physical growth. We did not include trials reporting only biochemical outcomes.

DATA COLLECTION AND ANALYSIS

Two review authors extracted data independently. We assessed risk of bias of included studies using the guidelines of the Cochrane Neonatal Review Group. When appropriate, we conducted meta-analysis to determine a pooled estimate of effect.

MAIN RESULTS

We identified 31 RCTs and included 15 of these in the review (N = 1889).Nine studies assessed visual acuity, six of which used visual evoked potentials (VEP), two Teller cards and one both. Four studies reported beneficial effects, and the remaining five did not. Meta-analysis of three RCTs showed significant benefit for sweep VEP acuity at 12 months (log of the minimum angle of resolution (logMAR)) (mean difference (MD) -0.15, 95% confidence interval (CI) -0.17 to -0.13; I² = 0; three trials; N = 244), but meta-analysis of three other RCTs showed no benefit for visual acuity measured with Teller cards at 12 months (cycles/degree) (MD -0.01, 95% CI -0.12 to 0.11; I² = 0; three trials; N = 256). GRADE analysis for the outcome of visual acuity indicated that the overall quality of evidence was low.Eleven studies measured neurodevelopmental outcomes at or before two years. Nine studies used Bayley Scales of Infant Development, version II (BSID-II), and only two of these studies reported beneficial effects. Meta-analysis revealed no significant differences between LCPUFA and placebo groups in BSID Mental Developmental Index (MDI) scores at 18 months (MD 0.06, 95% CI -2.01 to 2.14; I² = 75%; four trials; N = 661) and no significant differences in BSID Psychomotor Development Index (PDI) scores at 18 months (MD 0.69, 95% CI -0.78 to 2.16; I² = 61%; four trials; N = 661). Results showed no significant differences between the two groups in BSID-II scores at one year and two years of age. One study reported better novelty preference measured by the Fagan Infant Test at nine months. Another study reported better problem solving at 10 months. One study used the Brunet and Lezine test to assess the developmental quotient and found no beneficial effects. Follow-up of some infants in different studies at three, six and nine years of age revealed no beneficial effects of supplementation. GRADE analysis of these outcomes indicated that the overall quality of evidence was low.Thirteen studies measured physical growth; none found beneficial or harmful effects of supplementation. Meta-analysis of five RCTs showed that the supplemented group had lower weight (z scores) at one year of age (MD -0.23, 95% CI -0.40 to -0.06; I² = 83%; N = 521) and that the two groups showed no significant differences with respect to length and head circumference (z scores). Meta-analysis at 18 months and at two years revealed no significant differences between the two groups with respect to weight (kg), length (cm) and head circumference (cm). GRADE analysis of these outcomes indicated that the overall quality of evidence was low.

AUTHORS' CONCLUSIONS

Most of the included RCTs reported no beneficial effects or harms of LCPUFA supplementation on neurodevelopmental outcomes of formula-fed full-term infants and no consistent beneficial effects on visual acuity. Routine supplementation of full-term infant milk formula with LCPUFA cannot be recommended at this time.

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.

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.

Does docosahexaenoic acid supplementation in term infants enhance neurocognitive functioning in infancy?

The proposal that dietary docosahexaenoic acid (DHA) enhances neurocognitive functioning in term infants is controversial. Theoretical evidence, laboratory research and human epidemiological studies have convincingly demonstrated that DHA deficiency can negatively impact neurocognitive development. However, the results from randomized controlled trials (RCTs) of DHA supplementation in human term-born infants have been inconsistent. This article will (i) discuss the role of DHA in the human diet, (ii) explore the physiological mechanisms by which DHA plausibly influences neurocognitive capacity, and (iii) seek to characterize the optimal intake of DHA during infancy for neurocognitive functioning, based on existing research that has been undertaken in developed countries (specifically, within Australia). The major observational studies and RCTs that have examined dietary DHA in human infants and animals are presented, and we consider suggestions that DHA requirements vary across individuals according to genetic profile. It is important that the current evidence concerning DHA supplementation is carefully evaluated so that appropriate recommendations can be made and future directions of research can be strategically planned.

Long-chain omega-3 fatty acids: time to establish a dietary reference intake

The beneficial effects of consuming omega-3 polyunsaturated fatty acids (n-3 PUFAs), specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), on cardiovascular health have been studied extensively. To date, there is no dietary reference intake (DRI) for EPA and DHA, although many international authorities and expert groups have issued dietary recommendations for them. Given the substantial new evidence published since the last Institute of Medicine (IOM) report on energy and macronutrients, released in 2002, there is a pressing need to establish a DRI for EPA and DHA. In order to set a DRI, however, more information is needed to define the intakes of EPA and DHA required to reduce the burden of chronic disease. Information about potential gender- or race-based differences in requirements is also needed. Given the many health benefits of EPA and DHA that have been described since the 2002 IOM report, there is now a strong justification for establishing a DRI for these fatty acids.

DHA supplementation: current implications in pregnancy and childhood

Dietary supplementation with ω-3 long chain fatty acids including docosahexaenoic acid (DHA) has increased in popularity in recent years and adequate DHA supplementation during pregnancy and early childhood is of clinical importance. Some evidence has been built for the neuro-cognitive benefits of supplementation with long chain polyunsaturated fatty acids (LCPUFA) such as DHA during pregnancy; however, recent data indicate that the anti-inflammatory properties may be of at least equal significance. Adequate DHA availability in the fetus/infant optimizes brain and retinal maturation in part by influencing neurotransmitter pathways. The anti-inflammatory properties of LCPUFA are largely mediated through modulation of signaling either directly through binding to receptors or through changes in lipid raft formation and receptor presentation. Our goal is to review the current findings on DHA supplementation, specifically in pregnancy and infant neurodevelopment, as a pharmacologic agent with both preventative and therapeutic value. Given the overall benefits of DHA, maternal and infant supplementation may improve neurological outcomes especially in vulernable populations. However, optimal composition of the supplement and dosing and treatment strategies still need to be determined to lend support for routine supplementation.

Long-chain polyunsaturated fatty acid supplementation in infants born at term

BACKGROUND

The n-3 and n-6 fatty acids linolenic acid and linoleic acid are precursors of the n-3 and n-6 long chain fatty acids (LCPUFA). Infant formula has historically only contained the precursor fatty acids. Over the last few years, some manufacturers have added LCPUFA to formulae and marketed them as providing an advantage for the development of term infants.

OBJECTIVES

To assess whether supplementation of formula with LCPUFA is safe and of benefit to term infants.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library, April, 2011), MEDLINE (1966 to April 2011), EMBASE (1980 to April 2011), CINAHL (December 1982 to April 2011) and abstracts of the Society for Pediatric Research (1980 to 2010). No language restrictions were applied.

SELECTION CRITERIA

Randomised and quasi randomised trials comparing LCPUFA supplemented vs. non-supplemented formula milk and with clinical endpoints were reviewed.

DATA COLLECTION AND ANALYSIS

Methodological quality of studies was assessed using the guidelines of Cochrane neonatal review group. Data were sought regarding effects on visual acuity, neurodevelopmental outcomes and physical growth. When appropriate, meta-analysis was conducted to provide a pooled estimate of effect.

MAIN RESULTS

Twenty-five randomised studies were identified; fifteen were included (n = 1889) and ten excluded.Visual acuity was assessed by nine studies. Visual evoked potential was used in six studies, two used Teller cards and one used both. Four studies reported beneficial effects while the remaining five did not.Neurodevelopmental outcome was measured by eleven studies. Bayley scales of infant development (BSID) was used in nine studies; only two showed beneficial effects. Meta-analysis did not show significant benefits of supplementation. One study followed the infants up to nine years of age and did not find benefit of supplementation. One study reported better novelty preference measured by Fagan Infant test at nine months. Another study reported better problem solving at 10 months. One study used Brunet and Lezine test to assess the developmental quotient and did not find beneficial effects.Physical growth was measured by thirteen studies; none found beneficial or harmful effects of supplementation. Meta-analysis found that supplemented group may have marginally lower weight at one year of age.

AUTHORS' CONCLUSIONS

Majority of the RCTS have not shown beneficial effects of LCPUFA supplementation on the neurodevelopmental outcomes of term infants. The beneficial effects on visual acuity have not been consistently demonstrated. Routine supplementation of term infant milk formula with LCPUFA can not be recommended.