Lipid needs of preterm infants: updated recommendations

Effects of oral zinc supplementation on zinc status and catch-up growth during the first 2 years of life in children with non-organic failure to thrive born preterm and at term

BACKGROUND

We aimed to analyze the effect of oral zinc supplementation on serum insulin-like growth factor-1 (IGF-1) levels and catch-up growth in infants with non-organic failure to thrive (NOFTT) who were born preterm as compared to those born at term.

METHODS

Totally, 105 NOFTT infants aged 2 years or less were enrolled and divided into two groups according to gestational age at birth. Oral zinc sulfate was administered for 6 months to 49/66 children born at term, and 21/39 children born preterm. Serum zinc, IGF-1, weight, and height were measured at baseline and at 6 months.

RESULTS

There were no differences in baseline serum zinc levels between the two groups. In preterm NOFTT infants, zinc supplementation significantly increased serum zinc levels compared to those in the non-supplementation group (Δ zinc _{0-6 month} 10.3 ± 26.4 μg/dL vs. -8.8 ± 23.7 μg/dL, p = 0.018), but it did not significantly change serum IGF-1 levels or weight- and height for age Z-scores. In NOFTT infants born at term who received zinc supplementation, serum zinc levels, IGF-1, weight for age Z-score, and height for age Z-score increased at 6 months (p = 0.001, p = 0.014, p = 0.049, and p = 0.029, respectively), but this increase was not significantly greater than in the non-supplementation group. Only the increase in serum zinc levels was significant after 6 months (Δ zinc _{0-6 month} 16.8 ± 32.0 μg/dL vs. -10.0 ± 22.6 μg/dL, p = 0.002).

CONCLUSION

Zinc supplementation in NOFTT infants improves serum zinc status, regardless of gestational age at birth. Zinc supplementation in NOFTT infants born at term may improve serum IGF-1 levels and growth, but it does not in NOFTT infants born preterm. Overall nutritional support rather than supplementation of a single nutrient may be more effective for catch-up growth in NOFTT infants born preterm.

2018 Update on Pediatric Medical Overuse: A Review

IMPORTANCE

Efforts to combat medical overuse have gained traction in recent years, but success has been intermittent and shortcomings have been recognized. A commitment to a strong evidence base is needed to more broadly engage clinicians and reduce overuse.

OBSERVATIONS

A structured MEDLINE search and a manual review of tables of contents from selected high-impact journals was performed to identify original research published in 2017 relevant to pediatric overuse. Articles were scored from low to high for 3 categories: quality of methods, magnitude of potential harm, and number of patients potentially harmed. The top-scoring articles presented in this review highlight examples of safe reductions in treatment intensity, including in the setting of cancer, appendicitis, acute respiratory tract infection, and elective anesthesia. This year's articles also provide cautionary examples of rational interventions adopted without a full understanding of potential harms, including pharmacologic migraine therapies, docosahexaenoic acid supplementation for preterm neonates, tight glycemic control for individuals with critically illness, and prophylactic antibiotics for children with vesicoureteral reflux.

CONCLUSIONS AND RELEVANCE

The articles represent high-quality, original research from 2017 that may help mitigate overuse. These works should be fundamental to the maturation of the pediatric overuse field.

Lipid emulsions for parenterally fed preterm infants

This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:

The primary objective is to compare the effectiveness and safety of lipid formulations from different sources, including soybean oil‐based, multicomponent, olive oil‐based, and fish oil–based, in parenterally fed preterm infants.

The secondary objective is to determine the effectiveness and safety of alternative lipid emulsions compared with soybean oil‐based lipid emulsions in relation to gestational age (less than 30 weeks' gestation; 30 weeks' gestation or more), birth weight (1000 grams or less; more than 1000 grams), clinical condition (surgical patients, patients with established cholestasis).

Effect of Different Tube Feeding Methods on the Delivery of Docosahexaenoic and Arachidonic Acid: An In Vitro Pilot Study

BACKGROUND

Arachidonic acid (AA) and docosahexaenoic acid (DHA) are crucial for neural and visual development after premature birth. Preterm infants usually require tube feeding (TF) until the achievement of adequate oral feeding skills; the impact of TF on DHA and AA delivery has not been investigated yet. This study aimed to evaluate the effect of different TF techniques on the delivery of AA and DHA contained in human milk (HM).

METHODS

HM samples (65 mL each) were collected and divided into three 20-mL aliquots. The remaining 5 mL served as baseline. Three TF techniques were simulated (1 for each aliquot): gravity bolus feeding (BF), 3-hour continuous feeding using a horizontal feeding pump, and 3-hour continuous feeding with the feeding pump angled at 45°. For horizontal continuous feeding (HCF) and 45° angled continuous feeding (ACF), aliquots delivered between 0 and 90 minutes (T1) and 91 and 180 minutes (T2) were collected separately. AA and DHA concentration was analyzed by gas chromatography/mass spectrometry and compared among the TF methods. DHA and AA delivery at T1 and T2 was also evaluated.

RESULTS

Fifty-one simulated feeds were performed. DHA and AA amounts after BF and ACF did not differ significantly compared with baseline, whereas HCF resulted in significantly lower DHA and AA concentration. During T2, ACF delivered almost twice the DHA and AA amounts compared with T1.

CONCLUSION

The delivery of HM AA and DHA is significantly affected by TF, with potential clinical implications. When BF is not tolerated, ACF might represent a feasible alternative to reduce TF-related DHA and AA loss.

Carnitine deficiency in preterm infants: A national survey of knowledge and practices

OBJECTIVE

Lipid supplementation improves developmental outcomes in preterm infants. Carnitine is essential for lipid metabolism; however, despite high risk for carnitine deficiency, there are no standards for carnitine supplementation in preterm infants receiving total parenteral nutrition (TPN). Our objective was to assess knowledge, beliefs and practices regarding preterm carnitine deficiency and supplementation among neonatal practitioners.

METHODS

Cross-sectional electronic survey administered via a nationally representative listserv of neonatal practitioners.

RESULTS

492 respondents participated in the survey. Only 21% of respondents were aware that carnitine is secreted by the placenta. 72% believed that carnitine deficiency was common, and 60% believed deficiency could have serious consequences. Five percent routinely screened for deficiency, and 40% routinely provided carnitine supplementation. Respondents with >5 years' experience were more likely to report using carnitine supplementation (50% vs. 38%).

CONCLUSIONS

Although most respondents believed that carnitine deficiency is common and could have serious consequences, few screened for deficiency and fewer than half routinely supplemented. Thus, many preterm infants remain at risk for carnitine deficiency. Further research is needed to elucidate the risks of carnitine deficiency in these vulnerable infants.

Fat Loss in Continuous Enteral Feeding of the Preterm Infant: How Much, What and When Is It Lost?

Human milk fat is a concentrated source of energy and provides essential and long chain polyunsaturated fatty acids. According to previous experiments, human milk fat is partially lost during continuous enteral nutrition. However, these experiments were done over relatively short infusion times, and a complete profile of the lost fatty acids was never measured. Whether this loss happens considering longer infusion times or if some fatty acids are lost more than others remain unknown. Pooled breast milk was infused through a feeding tube by a peristaltic pump over a period of 30 min and 4, 12 and 24 h at 2 mL/h. Adsorbed fat was extracted from the tubes, and the fatty acid composition was analyzed by gas chromatography-mass spectrometry. Total fat loss (average fatty acid loss) after 24 h was 0.6 ± 0.1%. Total fat loss after 24 h infusion was 0.6 ± 0.1% of the total fat infused, although the highest losses occur in the first 30 min of infusion (13.0 ± 1.6%). Short-medium chain (0.7%, p = 0.15), long chain (0.6%, p = 0.56), saturated (0.7%, p = 0.4), monounsaturated (0.5%, p = 0.15), polyunsaturated fatty (0.7%, p = 0.15), linoleic (0.7%, p = 0.25), and docosahexaenoic acids (0.6%, p = 0.56) were not selectively adsorbed to the tube. However, very long chain fatty (0.9%, p = 0.04), alpha-linolenic (1.6%, p = 0.02) and arachidonic acids (1%, p = 0.02) were selectively adsorbed and, therefore, lost in a greater proportion than other fatty acids. In all cases, the magnitude of the loss was clinically low.

Long-chain polyunsaturated fatty acids decline rapidly in milk from mothers delivering extremely preterm indicating the need for supplementation

AIM

Our aim was to perform an in-depth analysis of the composition of fatty acids in milk from mothers delivering extremely preterm babies. We investigated longitudinal changes in milk fatty acid profiles and the relationship between several types of fatty acids, including omega-3 and omega-6.

METHODS

Milk samples were collected at three stages of lactation from 78 mothers who delivered at less than 28 weeks of pregnancy at the Sahlgrenska University Hospital, Gothenburg, Sweden, from April 2013 to September 2015. Fatty acid composition was analysed by gas chromatography-mass spectrometry.

RESULTS

A reduction in long-chain polyunsaturated fatty acids (LCPUFAs) was observed during the lactation period. The concentrations of arachidonic acid and docosahexaenoic acid declined from medians of 0.34 to 0.22 mol% and 0.29 to 0.15 mol%, respectively, between postnatal day 7 and a postmenstrual age of 40 weeks. Strong correlations were found between the intermediates of several classes of fatty acids, including omega-3, omega-6 and omega-9.

CONCLUSION

A rapid reduction in LCPUFA content in the mother's milk during the lactation period emphasises the importance of fatty acid supplementation to infants born extremely preterm, at least during the period corresponding to the third trimester, when rapid development of the brain and adipose tissue requires high levels of LCPUFAs.

Effects on Fatty Acid Metabolism of a New Powdered Human Milk Fortifier Containing Medium-Chain Triacylglycerols and Docosahexaenoic Acid in Preterm Infants

Preterm infants require fortification of human milk (HM) with essential fatty acids (FA) to ensure adequate post-natal development. As part of a larger randomized controlled study, we investigated FA metabolism in a subset of 47 clinically stable preterm infants (birth weight ≤1500 g or gestational age ≤32 weeks). Infants were randomized to receive HM supplemented with either a new HM fortifier (nHMF; n = 26) containing 12.5 g medium-chain FA (MCFA), 958 mg linoleic acid (LA), 417 mg α-linolenic acid (ALA), and 157 mg docosahexaenoic acid (DHA) per 100 g of powder (in compliance with the latest guidelines) or a fat-free HMF (cHMF; n = 21). Plasma phospholipid (PL) and triacylglycerol (TAG), and red blood cell phosphatidylcholine (RBC-PC) and phosphatidylethanolamine (RBC-PE) FA profiles were assessed before and after 21 days of feeding. In the nHMF group, significantly increased levels of n-9 monounsaturated fatty acids were observed, formed most likely by elongation and desaturation of dietary saturated fatty acids present in HM. ALA fortification increased ALA assimilation into plasma TAG. Similarly, DHA fortification enriched the DHA content in RBC-PE, which, in this compartment, was not associated with lower arachidonic acid levels as observed in plasma TAG and phospholipids. RBC-PE, a reliable indicator of FA metabolism and accretion, was the most sensitive compartment in this study.

Assessing whether early attention of very preterm infants can be improved by an omega-3 long-chain polyunsaturated fatty acid intervention: a follow-up of a randomised controlled trial

INTRODUCTION

Docosahexaenoic acid (DHA) accumulates in the frontal lobes (responsible for higher-order cognitive skills) of the fetal brain during the last trimester of pregnancy. Infants born preterm miss some of this in utero provision of DHA, and have an increased risk of suboptimal neurodevelopment. It is thought that supplementing infants born preterm with DHA may improve developmental outcomes. The aim of this follow-up is to determine whether DHA supplementation in infants born preterm can improve areas of the brain associated with frontal lobe function, namely attention and distractibility.

METHODS AND ANALYSIS

We will assess a subset of children from the N-3 (omega-3) Fatty Acids for Improvement in Respiratory Outcomes (N3RO) multicentre double-blind randomised controlled trial of DHA supplementation. Infants born <29 weeks' completed gestation were randomised to receive an enteral emulsion containing 60 mg/kg/day of DHA or a control emulsion from within the first 3 days of enteral feeding until 36 weeks' postmenstrual age.Children will undergo multiple measures of attention at 18 months' corrected age. The primary outcome is the average time to be distracted when attention is focused on a toy. Secondary outcomes are other aspects of attention, and (where possible) an assessment of cognition, language and motor development with the Bayley Scales of Infant and Toddler Development, Third Edition.A minimum of 72 children will be assessed to ensure 85% power to detect an effect on the primary outcome. Families, and research personnel are blinded to group assignment. All analyses will be conducted according to the intention-to-treat principal.

ETHICS AND DISSEMINATION

All procedures were approved by the relevant institutional ethics committees prior to commencement of the study. Results will be disseminated in peer-reviewed journal publications and academic presentations.

TRIAL REGISTRATION NUMBER

ACTRN12612000503820; Pre-results.

The Role of Lipids in Human Milk and Infant Formulae

The quantity and quality of dietary lipids in infant formulae have a significant impact on health outcomes, especially when fat storing and/or absorption are limited (e.g., preterm birth and short bowel disease) or when fat byproducts may help to prevent some pathologies (e.g., atopy). The lipid composition of infant formulae varies according to the different fat sources used, and the potential biological effects are related to the variety of saturated and unsaturated fatty acids. For example, since lipids are the main source of energy when the normal absorptive capacity of the digestive tract is compromised, medium-chain saturated fatty acids might cover this requirement. Instead, ruminant-derived trans fatty acids and metabolites of n-3 long-chain polyunsaturated fatty acids with their anti-inflammatory properties can modulate immune function. Furthermore, dietary fats may influence the nutrient profile of formulae, improving the acceptance of these products and the compliance with dietary schedules.

Influence of Human Milk and Parenteral Lipid Emulsions on Serum Fatty Acid Profiles in Extremely Preterm Infants

Background

Infants born prematurely are at risk of a deficiency in ω‐6 and ω‐3 long‐chain polyunsaturated fatty acids (LC‐PUFAs) arachidonic acid (AA) and docosahexaenoic acid (DHA). We investigated how fatty acids from breast milk and parenteral lipid emulsions shape serum LC‐PUFA profiles in extremely preterm infants during early perinatal life.

Methods

Ninety infants born < 28 weeks gestational age were randomized to receive parenteral lipids with or without the ω‐3 LC‐PUFAs eicosapentaenoic acid (EPA) and DHA (SMOFlipid: Fresenius Kabi, Uppsala, Sweden, or Clinoleic: Baxter Medical AB, Kista, Sweden, respectively). The fatty acid composition of infant serum phospholipids was determined from birth to postmenstrual age 40 weeks, and in mother's milk total lipids on postnatal day 7. Enteral and parenteral intake of LC‐PUFAs was correlated with levels in infant serum.

Results

Infants administered parenteral ω‐3 LC‐PUFAs received 4.4 and 19.3 times more DHA and EPA, respectively, over the first 2 weeks of life. Parenteral EPA but not DHA correlated with levels in infant serum. We found linear relationships between dietary EPA and DHA and infant serum levels in the Clinoleic (Baxter Medical AB) group. The volume of administered SMOFlipid (Fresenius Kabi) was inversely correlated with serum AA, whereas Clinoleic (Baxter Medical AB) inversely correlated with serum EPA and DHA.

Conclusions

There appears to be no or low correlation between the amount of DHA administered parenterally and levels measured in serum. Whether this observation reflects serum phospholipid fraction only or truly represents the amount of accreted DHA needs to be investigated. None of the parenteral lipid emulsions satisfactorily maintained high levels of both ω‐6 and ω‐3 LC‐PUFAs in infant serum.

Parenteral nutrition for preterm infants: Issues and strategy

Due to transient gut immaturity, most very preterm infants receive parenteral nutrition (PN) in the first few weeks of life. Yet providing enough protein and energy to sustain optimal growth in such infants remains a challenge. Extrauterine growth restriction is frequently observed in very preterm infants at the time of discharge from hospital, and has been found to be associated with later impaired neurodevelopment. A few recent randomized trials suggest that intensified PN can improve early growth; whether or not such early PN improves long-term neurological outcome is still unclear. Several other questions regarding what is optimal PN for very preterm infants remain unanswered. Amino acid mixtures designed for infants contain large amounts of branched-chain amino acids and taurine, but there is no consensus on the need for some nonessential amino acids such as glutamine, arginine, and cysteine. Whether excess growth in the first few weeks of life, at a time when very preterm infants receive PN, has an imprinting effect, increasing the risk of metabolic or vascular disease at adulthood continues to be debated. Even though uncertainty remains regarding the long-term effect of early PN, it appears reasonable to propose intensified initial PN. The aim of the current position paper is to review the evidence supporting such a strategy with regards to the early phase of nutrition, which is mainly covered by parenteral nutrition. More randomized trials are, however, needed to further support this type of approach and to demonstrate that this strategy improves short- and long-term outcome.

Docosahexaenoic acid and the preterm infant

Docosahexaenoic acid (DHA) is a long chain poly-unsaturated fatty acid (LCPUFA) that has a role in the cognitive and visual development, as well as in the immune function of newborns. Premature infants are typically deficient in DHA for several reasons, to include fetal accretion of DHA that typically occurs during the third trimester. These premature infants are reliant on enteral sources of DHA, most commonly through breast milk. The DHA content in breast milk varies in direct correlation with maternal DHA intake and mothers consuming a Western diet typically have lower levels of DHA in their breast milk. Maternal DHA supplementation and direct supplementation of DHA to the infant has been tried successfully but there are still conflicting results on the optimal dosage and method of delivery of DHA to the infant. This has led to inconsistent results in trials evaluating the effects of DHA supplementation to the preterm infant in terms of cognitive and immunological outcomes. While short-term benefits have been seen in several studies, long-term benefits are not consistent. Future studies continue to be needed to optimize DHA intake in our premature infants.

Postnatal RBC arachidonic and docosahexaenoic acids deficiencies are associated with higher risk of neonatal morbidities and mortality in preterm infants

Arachidonic (AA) and docosahexaenoic (DHA) acids are essential for the health and development of the neonate. Red blood cell (RBC) fatty acids were analyzed in 583 very low birth weight (VLBW) infants and 274 term infants using capillary gas chromatography. VLBW infants exhibited significantly lower RBC AA (13.0 ± 0.89 vs. 13.5 ± 0.98) and DHA (3.77 ± 0.60 vs. 3.80 ± 0.62), but higher n6:n3 ratio (3.97 ± 0.46 vs. 3.63 ± 0.37) than term infants. In VLBW infants, DHA was lower in those born with small for gestational age (3.69 ± 0.57 vs. 3.86 ± 0.58) and those who suffered from neonatal sepsis (3.73 ± 0.60 vs. 3.86 ± 0.55). Both AA and DHA were significantly lower in infants who developed respiratory distress syndrome or intraventricular hemorrhage, and those who died during the hospital stay. VLBW infants had lower postnatal RBC AA and DHA levels than term infants did. These deficits are associated with higher risk of neonatal morbidities and mortality.

ω-3 and ω-6 long-chain PUFAs and their enzymatic metabolites in neovascular eye diseases

Neovascular eye diseases, including retinopathy of prematurity, diabetic retinopathy, and age-related macular degeneration, threaten the visual health of children and adults. Current treatment options, including anti-vascular endothelial growth factor therapy and laser retinal photocoagulation, have limitations and are associated with adverse effects; therefore, the identification of additional therapies is highly desirable. Both clinical and experimental studies show that dietary ω-3 (n-3) long-chain polyunsaturated fatty acids (LC-PUFAs) reduce retinal and choroidal angiogenesis. The ω-3 LC-PUFA metabolites from 2 groups of enzymes, cyclooxygenases and lipoxygenases, inhibit [and the ω-6 (n-6) LC-PUFA metabolites promote] inflammation and angiogenesis. However, both of the ω-3 and the ω-6 lipid products of cytochrome P450 oxidase 2C promote neovascularization in both the retina and choroid, which suggests that inhibition of this pathway might be beneficial. This review summarizes our current understanding of the roles of ω-3 and ω-6 LC-PUFAs and their enzymatic metabolites in neovascular eye diseases.

Docosahexaenoic acid (DHA) and arachidonic acid (ARA) balance in developmental outcomes

The DHA Intake and Measurement of Neural Development (DIAMOND) trial represents one of only a few studies of the long-term dose-response effects of LCPUFA-supplemented formula feeding during infancy. The trial contrasted the effects of four formulations: 0.00% docosahexaenoic acid (DHA)/0.00% arachidonic acid (ARA), 0.32% DHA/0.64% ARA, 0.64% DHA/0.64% ARA, and 0.96% DHA/0.64% ARA against a control condition (0.00% DHA/0.00% ARA). The results of this trial have been published elsewhere, and show improved cognitive outcomes for infants fed supplemented formulas, but a common finding among many of the outcomes show a reduction of benefit for the highest DHA dose (i.e., 0.96%DHA/0.64% ARA, that is, a DHA: ARA ratio 1.5:1.0). The current paper gathers and summarizes the evidence for the reduction of benefit at this dose, and in an attempt to account for this reduced benefit, presents for the first time data from infants' red blood cell (RBC) assays taken at 4 and 12 months of age. Those assays indicate that blood DHA levels generally rose with increased DHA supplementation, although those levels tended to plateau as the DHA-supplemented level exceeded 0.64%. Perhaps more importantly, ARA levels showed a strong inverted-U function in response to increased DHA supplementation; indeed, infants assigned to the formula with the highest dose of DHA (and highest DHA/ARA ratio) showed a reduction in blood ARA relative to more intermediate DHA doses. This finding raises the possibility that reduced ARA may be responsible for the reduction in benefit on cognitive outcomes seen at this dose. The findings implicate the DHA/ARA balance as an important variable in the contribution of LCPUFAs to cognitive and behavioral development in infancy.

Effects of a lipid emulsion containing fish oil on polyunsaturated fatty acid profiles, growth and morbidities in extremely premature infants: A randomized controlled trial

BACKGROUND & AIMS

The purpose of the study was to compare the effects of the parenteral emulsion SMOFlipid^®, with 15% fish oil, with Clinoleic^® on retinopathy of prematurity (ROP) and other morbidities and growth, and to compare their impact on longitudinal serum levels of fatty acids. Retinopathy of prematurity, other morbidity and growth were correlated with each parenteral lipid supplement.

METHODS

Ninety infants born at gestational age <28 weeks were randomized to treatment with SMOFlipid^® or Clinoleic^®. Two thirds (66%) of the infants received parenteral nutrition for up to 14 days birth (median 8, range 2-14 days), and additional 25% of the infants received for up to 28 days after birth (median 21, range 15-28 days). Cord blood samples and then venous blood samples were obtained at ages 1, 7, 14, and 28 days and at postmenstrual age (PMA) 32, 36, and 40 weeks. Breastmilk was collected at postnatal day 7, and at PMA 32 and 40 weeks. Serum phospholipid and breastmilk total fatty acids were analyzed by gas chromatography-mass spectrometry. Treatment groups were compared with regard to ROP, bronchopulmonary dysplasia, necrotizing enterocolitis, patent ductus arteriosus sepsis and growth between birth and 36 weeks.

RESULTS

Infants on SMOFlipid^® had higher fractions of omega-3 LCPUFA eicosapentaenoic acid (EPA) and slightly higher omega-3 LCPUFA docosahexaenoic acid (DHA) fraction and a decreased arachidonic acid (AA) to DHA ratio from one week after birth up to 32 postmenstrual weeks compared to infants on Clinoleic^®. Treatment groups did not differ in morbidities or growth.

CONCLUSION

Supplementation with SMOFlipid^® containing 15% fish oil during parenteral nutrition increased EPA substantially, DHA marginally, reduced AA and decreased AA to DHA ratio. It did not reduce morbidity or affect growth. Since extremely preterm infants accumulate a large deficit of DHA and AA, studies on more prolonged or different levels of DHA and AA supplementation are warranted.

Effects of Maternal Supplementation With Omega-3 Precursors on Human Milk Composition

BACKGROUND

Long-chain polyunsaturated fatty acids (LC-PUFAs) are important for newborn neurosensory development. Supplementation of breastfeeding mothers' diets with omega-3 PUFAs, such as alpha-linolenic acid (ALA), may increase their concentration in human milk. Research aim: This study aimed to assess human milk composition after 15-day supplementation regimens containing either omega-3 PUFAs or olive oil, which does not provide ALA.

METHODS

A multicenter factorial randomized trial was conducted with four groups of breastfeeding women, with each group containing 19 to 22 women. After a 15-day ALA washout period, three groups received supplementation with omega-3 precursors for 15 days: an enriched margarine (M), a rapeseed oil (R), and a margarine and rapeseed oil (MR). The fourth was unexposed to omega-3 precursors (olive oil control diet, O). After 15 days, blind determination of human milk fatty acid (FA) composition was assessed by gas chromatography, and the FA composition was compared among groups using variance analyses.

RESULTS

Alpha-linolenic acid content, expressed as the mean (standard deviation) total human milk FA percentage, was significantly higher after diet supplementation with omega-3 PUFAs, with values of 2.2% (0.7%) (MR), 1.3% (0.5%) (R), 1.1% (0.4%) (M), and 0.8% (0.3%) (O at D30) ( p < .003 for each comparison). The lowest LA-ALA ratio (5.5) was found in the MR group ( p < .001). Docosahexaenoic acid and trans FA concentrations did not differ among groups.

CONCLUSION

In lactating women, omega-3 supplementation via the combination of enriched margarine and rapeseed oil increased the ALA content of human milk and generated the most favorable LA-ALA ratio for LC-PUFA synthesis.

Docosahexaenoic Acid and Bronchopulmonary Dysplasia in Preterm Infants

BACKGROUND

Studies in animals and in humans have suggested that docosahexaenoic acid (DHA), an n-3 long-chain polyunsaturated fatty acid, might reduce the risk of bronchopulmonary dysplasia, but appropriately designed trials are lacking.

METHODS

We randomly assigned 1273 infants born before 29 weeks of gestation (stratified according to sex, gestational age [<27 weeks or 27 to <29 weeks], and center) within 3 days after their first enteral feeding to receive either an enteral emulsion providing DHA at a dose of 60 mg per kilogram of body weight per day or a control (soy) emulsion without DHA until 36 weeks of postmenstrual age. The primary outcome was bronchopulmonary dysplasia, defined on a physiological basis (with the use of oxygen-saturation monitoring in selected infants), at 36 weeks of postmenstrual age or discharge home, whichever occurred first.

RESULTS

A total of 1205 infants survived to the primary outcome assessment. Of the 592 infants assigned to the DHA group, 291 (49.1% by multiple imputation) were classified as having physiological bronchopulmonary dysplasia, as compared with 269 (43.9%) of the 613 infants assigned to the control group (relative risk adjusted for randomization strata, 1.13; 95% confidence interval [CI], 1.02 to 1.25; P=0.02). The composite outcome of physiological bronchopulmonary dysplasia or death before 36 weeks of postmenstrual age occurred in 52.3% of the infants in the DHA group and in 46.4% of the infants in the control group (adjusted relative risk, 1.11; 95% CI, 1.00 to 1.23; P=0.045). There were no significant differences between the two groups in the rates of death or any other neonatal illnesses. Bronchopulmonary dysplasia based on a clinical definition occurred in 53.2% of the infants in the DHA group and in 49.7% of the infants in the control group (P=0.06).

CONCLUSIONS

Enteral DHA supplementation at a dose of 60 mg per kilogram per day did not result in a lower risk of physiological bronchopulmonary dysplasia than a control emulsion among preterm infants born before 29 weeks of gestation and may have resulted in a greater risk. (Funded by the Australian National Health and Medical Research Council and others; Australian New Zealand Clinical Trials Registry number, ACTRN12612000503820 .).

Reduction of Arachidonate Is Associated With Increase in B-Cell Activation Marker in Infants: A Randomized Trial

BACKGROUND

Infants who are not breast-fed benefit from formula with both docosahexaenoic acid (C22:6n3) and arachidonic acid (ARA; C20:4n6). The amount of ARA needed to support immune function is unknown. Infants who carry specific fatty acid desaturase (FADS) polymorphisms may require more dietary ARA to maintain adequate ARA status.

OBJECTIVE

The aim of the study was to determine whether ARA intake or FADS polymorphisms alter ARA levels of lymphocytes, plasma, and red blood cells in term infants fed infant formula.

METHODS

Infants (N = 89) were enrolled in this prospective, double-blind controlled study. Infants were randomized to consume formula containing 17 mg docosahexaenoic acid and 0, 25, or 34 mg ARA/100 kcal for 10 weeks. Fatty acid composition of plasma phosphatidylcholine and phosphatidylethanolamine, total fatty acids of lymphocytes and red blood cells, activation markers of lymphocytes, and polymorphisms in FADS1 and FADS2 were determined.

RESULTS

Lymphocyte ARA was higher in the 25-ARA formula group than in the 0- or 34-ARA groups. In plasma, 16:0/20:4 and 18:0/20:4 species of phosphatidylcholine and phosphatidylethanolamine were highest and 16:0/18:2 and 18:0/18:2 were lowest in the 34-ARA formula group. In minor allele carriers of FADS1 and FADS2, plasma ARA content was elevated only at the highest level of ARA consumed. B-cell activation marker CD54 was elevated in infants who consumed formula containing no ARA.

CONCLUSIONS

ARA level in plasma is reduced by low ARA consumption and by minor alleles in FADS. Dietary ARA may exert an immunoregulatory role on B-cell activation by decreasing 16:0/18:2 and 18:0/18:2 species of phospholipids. ARA intake from 25 to 34 mg/100 kcal is sufficient to maintain cell ARA level in infants across genotypes.

Fatty acid requirements for the preterm infant

Fatty acids are critical nutrient regulators of intracellular signaling and influence key pathways including inflammatory responses, hemostasis as well as central nervous system development and function. Preterm birth interrupts the maternal-fetal transfer of essential fatty acids including docosahexaenoic and arachidonic acids, which occurs during the third trimester. Postnatal deficits of these nutrients accrue in preterm infants during the first week and they remain throughout the first months. Due to the regulatory roles of these fatty acids, such deficits contribute an increased risk of developing prematurity-related morbidities including impaired growth and neurodevelopment. The fatty acid contents of parenteral and enteral nutrition are insufficient to meet current recommendations. This chapter summarizes the regulatory roles of fatty acids, current recommendations and limitations of parenteral and enteral nutrition in meeting these recommendations in preterm infants. Suggested areas for research on the roles of fatty acids in preterm infant health are also provided.

Extremely preterm infants receiving standard care receive very low levels of arachidonic and docosahexaenoic acids

BACKGROUND & AIMS

Adequate supply of arachidonic (ARA) and docosahexaenoic (DHA) acids is essential for brain development, and extremely preterm infants may be at risk of deficiency. Current levels of ARA and DHA given to extremely preterm infants and the amounts available for accretion have not been established, although recent evidence suggests DHA intake is at a level likely to lead to severe deficits. This study quantified the omega-6 and omega-3 polyunsaturated fatty acid (PUFA) intakes from all sources in the first six weeks of life of preterm infants in standard care. In addition, the relationship between blood levels of circulating cytokines and PUFAs was explored.

METHODS

Single centre longitudinal study with omega-6 and omega-3 PUFA intake data analysed from all sources for 17 infants born <28 weeks gestation. At six weeks of age the infants' whole-blood fatty acid levels were measured along with a range of cytokines and chemokines analysed by Luminex^® multiplex array.

RESULTS

ARA intake was significantly below international recommendations in weeks 1-5 (all p < 0.05), and DHA intake was significantly below recommendations in week 1 (p < 0.0001). The amounts of ARA and DHA available for accretion were significantly below estimated accretion rates in all weeks (all p < 0.001). Mean ARA and DHA intakes were correlated with their respective blood levels (r = 0.568, p = 0.017 and r = 0.704, p = 0.002). There were significant relationships between MIP-1β and blood DHA levels (rs = 0.559, p = 0.02) and between RANTES and omega-6:omega-3 PUFA ratio (rs = -0.498, p = 0.042).

CONCLUSIONS

This study establishes that extremely preterm infants receive insufficient intakes of ARA and DHA. Moreover, blood fatty acid levels may provide a useful measure of intake, where establishing sufficient consumption could have clinical importance. There may also be important interactions between long-chain PUFA status and markers of inflammation, which requires further study.

Multi-omic profiles of hepatic metabolism in TPN-fed preterm pigs administered new generation lipid emulsions

We aimed to characterize the lipidomic, metabolomic, and transcriptomic profiles in preterm piglets administered enteral (ENT) formula or three parenteral lipid emulsions [parenteral nutrition (PN)], Intralipid (IL), Omegaven (OV), or SMOFlipid (SL), for 14 days. Piglets in all parenteral lipid groups showed differential organ growth versus ENT piglets; whole body growth rate was lowest in IL piglets, yet there were no differences in either energy expenditure or (13)C-palmitate oxidation. Plasma homeostatic model assessment of insulin resistance demonstrated insulin resistance in IL, but not OV or SL, compared with ENT. The fatty acid and acyl-CoA content of the liver, muscle, brain, and plasma fatty acids reflected the composition of the dietary lipids administered. Free carnitine and acylcarnitine (ACT) levels were markedly reduced in the PN groups compared with ENT piglets. Genes associated with oxidative stress and inflammation were increased, whereas those associated with alternative pathways of fatty acid oxidation were decreased in all PN groups. Our results show that new generation lipid emulsions directly enrich tissue fatty acids, especially in the brain, and lead to improved growth and insulin sensitivity compared with a soybean lipid emulsion. In all total PN groups, carnitine levels are limiting to the formation of ACTs and gene expression reflects the stress of excess lipid on liver function.

Docosahexaenoic Acid Slows Visual Field Progression in X-Linked Retinitis Pigmentosa: Ancillary Outcomes of the DHAX Trial

PURPOSE

Docosahexaenoic acid (DHA) was supplemented in a single-site, placebo-controlled, randomized clinical trial designed to slow vision loss associated with X-linked retinitis pigmentosa (XLRP); the DHAX Trial. We previously reported no significant differences between supplemented and placebo groups in intent-to-treat analysis of primary ERG outcomes. Assessed herein are hypothesis-generating measures of ancillary visual function outcomes in participants fully adhering to trial protocol.

METHODS

Male participants with XLRP (range, 7-31 years) received 30 mg DHA/kg/d (n = 29) or placebo (n = 22) for 4 years. Visual outcomes were measured annually and red blood cell (RBC) DHA determined every 6 months.

RESULTS

Oral DHA supplementation increased mean RBC-DHA levels by 4-fold (P < 0.0001) over placebo. No group differences in progression were found for visual acuity (P = 0.11), shape discrimination (P = 0.18), or fundus appearance (P = 0.70). Optical coherence tomography (OCT) became available during year 2 of the trial; no group differences were seen in ellipsoid zone constriction (P = 0.87) over 2 years. Yearly rates of progression were reduced for dark-adapted thresholds (P = 0.06) and visual field sensitivity for foveal, macular, peripheral, total, and ellipsoid zone regions by DHA supplementation (P = 0.039, P = 0.031, P < 0.0001, P < 0.0001, and P = 0.033). Rates of visual field sensitivity decline were dependent on RBC-DHA (P = 0.046 to <0.0001).

CONCLUSIONS

Supplementation of DHA significantly elevated blood DHA levels and reduced the rate of progression in final dark-adapted thresholds and visual field sensitivity. From the relationship between RBC-DHA and the rate of field sensitivity loss, we can extrapolate that an RBC-DHA level of 17% could minimize the decline in field sensitivity. (ClinicalTrials.gov number, NCT00100230.)

Long-chain polyunsaturated fatty acids and the preterm infant: a case study in developmentally sensitive nutrient needs in the United States

The vast majority of infant formulas in the United States contain the long-chain polyunsaturated fatty acids (PUFAs) docosahexaenoic acid (22:6n-3) and arachidonic acid (20:4n-6), which were first permitted by the US Food and Drug Administration in 2001. As a scientific case study, preclinical animal studies of these nutrients definitively influenced the design and interpretation of human clinical studies. Early studies were tied to the availability of test substances, and in hindsight suggest re-evaluation of the essential fatty acid concept in light of the totality of available evidence. Research in the 1950s established the essentiality of n-6 PUFAs for skin integrity; however, widespread recognition of the essentiality of n-3 PUFAs came decades later despite compelling evidence of their significance. Barriers to an understanding of the essentiality of n-3 PUFAs were as follows: 1) their role is in neural function, which is measured only with difficulty compared with skin lesions and growth faltering that are apparent for n-6 PUFAs; 2) the experimental use of vegetable oils as PUFA sources that contain the inefficiently used C18 PUFAs rather than the operative C20 and C22 PUFAs; 3) the shift from reliance on high-quality animal studies to define mechanisms that established the required nutrients in the first part of the 20th century to inherently challenging human studies. Advances in nutrition of premature infants require the best practices and opinions available, taking into account the totality of preclinical and clinical evidence.

Alternative lipid emulsions versus pure soy oil based lipid emulsions for parenterally fed preterm infants

BACKGROUND

The pure soybean oil based lipid emulsions (S-LE) conventionally used for parenteral nutrition (PN) in preterm infants have high polyunsaturated fatty acid (PUFA) content. The newer lipid emulsions (LE) from alternative lipid sources with reduced PUFA content may improve clinical outcomes in preterm infants.

OBJECTIVES

To determine the safety and efficacy of the newer alternative LE compared with the conventional S-LE for PN in preterm infants.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group (CNRG) to search the Cochrane Central Register of Controlled Trials (CENTRAL; Issue 7), MEDLINE (1946 to 31 July 2015), EMBASE (1947 to 31 July 2015), CINAHL (1982 to 31 July 2015), Web of Science (31 July 2015), conference proceedings, trial registries (clinicaltrials.gov, controlled-trials.com, WHO's ICTRP), and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials in preterm infants (< 37 weeks), comparing newer alternative LE with S-LE.

DATA COLLECTION AND ANALYSIS

Data collection and analysis conformed to the methods of the CNRG. We assessed the quality of evidence for important outcomes using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, in addition to reporting the conventional statistical significance of results.

MAIN RESULTS

Fifteen studies (N = 979 infants) are included in this review. Alternative LE including medium chain triglycerides/long chain triglycerides (MCT/LCT) LE (3 studies; n = 108), MCT-olive-fish-soy oil-LE (MOFS-LE; 7 studies; n = 469), MCT-fish-soy oil-LE (MFS-LE; 1 study; n = 60), olive-soy oil-LE (OS-LE; 7 studies; n = 406), and borage-soy oil-LE (BS-LE; 1 study; n = 34) were compared with S-LE. The different LE were also considered together to compare 'all fish oil containing-LE' versus S-LE (7 studies; n = 499) and 'all alternative LE' versus S-LE (15 studies; n = 979). Some studies had multiple intervention arms and were included in more than one comparison. No study compared pure fish oil-LE or structured-LE to S-LE.The GRADE quality of evidence (GRADE QoE) ranged from 'low' to 'very low.' Evidence came mostly from small single centre studies, many focusing on biochemical aspects as their primary outcomes, with optimal information size not achieved for the important clinical outcomes in any comparison.In the primary outcomes of the review there was a pooled effect towards decreased bronchopulmonary dysplasia (BPD) in OS-LE vs S-LE (4 studies, n = 261) not reaching statistical significance (typical risk ratio (RR) 0.69, 95% confidence interval (CI) 0.46 to 1.04, I² = 32%; typical risk difference (RD) -0.08, 95% CI -0.17 to 0.00, I² = 76%; GRADE QoE: 'very low'). No difference in BPD was observed in any other comparison. There were no statistically significant differences in the primary outcomes of death, growth rate (g/kg/day) or days to regain birth weight in any comparison.Retinopathy of prematurity (ROP) stage 1-2 was reported to be statistically significantly lower in one single centre study (n = 80) in the MOFS-LE group compared with the S-LE group (1/40 vs 12/40, respectively; RR 0.08, 95% CI 0.01 to 0.61; RD -0.27, 95% CI -0.43 to -0.12; number needed to benefit (NNTB) 4, 95% CI 2 to 8). However there were no statistically significant differences in the secondary outcome of ROP ≥ stage 3 in any of the individual studies or in any comparison (GRADE QoE: 'low' to 'very low'). No other study reported on ROP stages 1 and 2 separately.There were no statistically significant differences in the secondary outcomes of sepsis, PN associated liver disease (PNALD)/cholestasis, ventilation duration, necrotising enterocolitis (NEC) ≥ stage 2, jaundice requiring treatment, intraventricular haemorrhage grade III-IV, periventricular leukomalacia (PVL), patent ductus arteriosus (PDA), hypertriglyceridaemia, and hyperglycaemia in any comparison.No study reported on neurodevelopmental outcomes or essential fatty acid deficiency.

AUTHORS' CONCLUSIONS

All lipid emulsions in this review appeared to be safe and were well tolerated in preterm infants. Compared with the pure soy oil based LE, use of MOFS-LE was associated with a decrease in the early stages (1-2) of ROP in one study. However there were no statistically significant differences in clinically important outcomes including death, growth, BPD, sepsis, ROP ≥ stage 3, and PNALD with the use of newer alternative LE versus the conventional pure soy oil based LE (GRADE QoE ranged from 'low' to 'very low'). Currently there is insufficient evidence to recommend any alternative LE over S-LE or vice versa in preterm infants.Larger randomised studies focusing on important clinical outcomes, targeting specific 'at risk' population subgroups (e.g. extreme prematurity, long term PN, etc), and exploring the effect of different proportions of lipid constituents are required to evaluate the effectiveness of newer lipid emulsions compared with the conventional pure soy based LE in preterm infants.

The fatty acid desaturase 2 (FADS2) gene product catalyzes Δ4 desaturation to yield n-3 docosahexaenoic acid and n-6 docosapentaenoic acid in human cells

Docosahexaenoic acid (DHA) is a Δ4-desaturated C22 fatty acid and the limiting highly unsaturated fatty acid (HUFA) in neural tissue. The biosynthesis of Δ4-desaturated docosanoid fatty acids 22:6n-3 and 22:5n-6 are believed to proceed via a circuitous biochemical pathway requiring repeated use of a fatty acid desaturase 2 (FADS2) protein to perform Δ6 desaturation on C24 fatty acids in the endoplasmic reticulum followed by 1 round of β-oxidation in the peroxisomes. We demonstrate here that the FADS2 gene product can directly Δ4-desaturate 22:5n-3→22:6n-3 (DHA) and 22:4n-6→22:5n-6. Human MCF-7 cells lacking functional FADS2-mediated Δ6-desaturase were stably transformed with FADS2, FADS1, or empty vector. When incubated with 22:5n-3 or 22:4n-6, FADS2 stable cells produce 22:6n-3 or 22:5n-6, respectively. Similarly, FADS2 stable cells when incubated with d5-18:3n-3 show synthesis of d5-22:6n-3 with no labeling of 24:5n-3 or 24:6n-3 at 24 h. Further, both C24 fatty acids are shown to be products of the respective C22 fatty acids via elongation. Our results demonstrate that the FADS2 classical transcript mediates direct Δ4 desaturation to yield 22:6n-3 and 22:5n-6 in human cells, as has been widely shown previously for desaturation by fish and many other organisms.

Challenges in breast milk fortification for preterm infants

PURPOSE OF REVIEW

To outline new evidence published from 2013 to 2014 about breast milk fortification in preterm infants.

RECENT FINDINGS

Breast milk is the feeding choice for preterm infants because of its immunoprotective properties. However, breast milk's nutrient content is not sufficient for preterm infants, and interindividual variation is high. The variation challenges standard fortification, which assumes a standard breast milk composition. Two new fortification strategies (adjustable fortification and target fortification) optimize macronutrient intake and improve growth. Adjustable fortification uses blood urea nitrogen levels to adjust fortifier strength. Target fortification analyzes breast milk and fortifies macronutrients individually to achieve targeted intake. Its feasibility is shown in clinical routine. Current breast milk analyzers used for target fortification achieve acceptable precision for protein and fat but not for lactose and energy. Evidence of benefits for postdischarge breast milk fortification is lacking. Eliminating cow's milk products and feeding exclusively breast milk may decrease the occurrence of feeding intolerance and necrotizing enterocolitis. To facilitate exclusively breast milk diets, a collaboration of prenatal, nutrition and lactation stakeholders is key. Fortification increases osmolality; however, safety cutoffs to prevent necrotizing enterocolitis are unclear. There is also new evidence that composition and structure of various macronutrients and micronutrients affect growth and development, and might play a role in future fortification concepts.

SUMMARY

Recent research focuses on the variability of breast milk composition, its impact on postnatal growth patterns and the usefulness of target fortification. As well, diets exclusively composed of human milk are a promising approach to improve feeding tolerance. For safe fortification, osmolality cutoff levels are needed.

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.

Is there a difference in breast milk fatty acid composition of mothers of preterm and term infants?

OBJECTIVE

Arachidonic acid (ARA) (c20:4 w6) and docosahexanoic acid (DHA) (c22:6 w3) are of major importance for neural maturation and retinal function in infancy. Requirements in preterm infants are increased due to accelerated growth and limited body stores. Data regarding human milk fatty acid composition after preterm and full-term delivery is inconsistent. This study compared fatty acid composition in breast milk from full-term and preterm infants. Findings were correlated with maternal dietary intake.

METHODS

Human milk was obtained 4-5 days after full-term delivery (20 infants) and 4-5, 10-11 and 14-15 days after preterm delivery (21 infants, of whom 6 were born before 30 weeks). For fatty acid analysis, lipids were extracted, transesterified and separated by gas liquid chromatography.

RESULTS

Total fat content was similar in the two groups. FA composition including LCPUFA and specifically ARA & DHA were similar in full-term and preterm infants and in the sub-set born before 30 weeks. In preterm infants, postnatal age did not influence LCPUFA content.

CONCLUSIONS

This study did not detect any effect of gestational age or postnatal age on milk LCPUFA content. Accordingly, the increased demand for LCPUFA and specifically DHA in preterm infants need to be met by other supplementation.

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.

A review of the impact of dietary intakes in human pregnancy on infant birthweight

Studies assessing maternal dietary intakes and the relationship with birthweight are inconsistent, thus attempting to draw inferences on the role of maternal nutrition in determining the fetal growth trajectory is difficult. The aim of this review is to provide updated evidence from epidemiological and randomized controlled trials on the impact of dietary and supplemental intakes of omega-3 long-chain polyunsaturated fatty acids, zinc, folate, iron, calcium, and vitamin D, as well as dietary patterns, on infant birthweight. A comprehensive review of the literature was undertaken via the electronic databases Pubmed, Cochrane Library, and Medline. Included articles were those published in English, in scholarly journals, and which provided information about diet and nutrition during pregnancy and infant birthweight. There is insufficient evidence for omega-3 fatty acid supplements’ ability to reduce risk of low birthweight (LBW), and more robust evidence from studies supplementing with zinc, calcium, and/or vitamin D needs to be established. Iron supplementation appears to increase birthweight, particularly when there are increases in maternal hemoglobin concentrations in the third trimester. There is limited evidence supporting the use of folic acid supplements to reduce the risk for LBW; however, supplementation may increase birthweight by ~130 g. Consumption of whole foods such as fruit, vegetables, low-fat dairy, and lean meats throughout pregnancy appears beneficial for appropriate birthweight. Intervention studies with an understanding of optimal dietary patterns may provide promising results for both maternal and perinatal health. Outcomes from these studies will help determine what sort of dietary advice could be promoted to women during pregnancy in order to promote the best health for themselves and their baby.

Four-year placebo-controlled trial of docosahexaenoic acid in X-linked retinitis pigmentosa (DHAX trial): a randomized clinical trial

IMPORTANCE

X-linked retinitis pigmentosa is a severe inherited retinal degenerative disease with a frequency of 1 in 100,000 persons. Because no cure is available for this orphan disease and treatment options are limited, slowing of disease progression would be a meaningful outcome.

OBJECTIVE

To determine whether high-dose docosahexaenoic acid (DHA), an ω-3 polyunsaturated fatty acid, slows progression of X-linked retinitis pigmentosa measured by cone electroretinography (ERG).

DESIGN, SETTING, AND PARTICIPANTS

A 4-year, single-site, randomized, placebo-controlled, double-masked phase 2 clinical trial at a research center specializing in medical retina. Seventy-eight male patients diagnosed as having X-linked retinitis pigmentosa were randomized to DHA or placebo. Data were omitted for 2 patients with non-X-linked retinitis pigmentosa and 16 patients who were unable to follow protocol during the first year. The remaining participants were tested annually and composed a modified intent-to-treat cohort (DHA group, n = 33; placebo group, n = 27).

INTERVENTIONS

All participants received a multivitamin and were randomly assigned to oral DHA (30 mg/kg/d) or placebo.

MAIN OUTCOMES AND MEASURES

The primary outcome was the rate of loss of cone ERG function. Secondary outcomes were rod and maximal ERG amplitudes and cone ERG implicit times. Capsule counts and red blood cell DHA levels were assessed to monitor adherence.

RESULTS

Average (6-month to 4-year) red blood cell DHA levels were 4-fold higher in the DHA group than in the placebo group (P < .001). There was no difference between the DHA and placebo groups in the rate of cone ERG functional loss (0.028 vs 0.022 log µV/y, respectively; P = .30). No group differences were evident for change in rod ERG (P = .27), maximal ERG (P = .65), or cone implicit time (no change over 4 years). The rate of cone loss (ie, event rate) was markedly reduced compared with rates in previous studies. No severe treatment-emergent adverse events were found.

CONCLUSIONS AND RELEVANCE

Long-term DHA supplementation was not effective in slowing the loss of cone or rod ERG function associated with X-linked retinitis pigmentosa. Participant dropout and lower-than-expected disease event rate limited power to detect statistical significance. A larger sample size, longer trial, and attainment of a target blood DHA level (13%) would be desirable. While DHA supplementation at 30 mg/kg/d does not present serious adverse effects, routine monitoring of gastrointestinal tolerance is prudent.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00100230.

Safety assessment of docosahexaenoic acid in X-linked retinitis pigmentosa: the 4-year DHAX trial

PURPOSE

Docosahexaenoic acid (DHA) continues to be evaluated and recommended as treatment and prophylaxis for various diseases. We recently assessed efficacy of high-dose DHA supplementation to slow vision loss in patients with X-linked retinitis pigmentosa (XLRP) in a randomized clinical trial. Because DHA is a highly unsaturated fatty acid, it could serve as a target for free-radical induced oxidation, resulting in increased oxidative stress. Biosafety was monitored during the 4-year trial to determine whether DHA supplementation was associated with identifiable risks.

METHODS

Males (n = 78; 7-31 years) meeting entry criteria were enrolled. The modified intent-to-treat cohort (DHA = 33; placebo = 27) adhered to the protocol ≥ 1 year. Participants were randomized to an oral dose of 30 mg/kg/d DHA or placebo plus a daily multivitamin. Comprehensive metabolic analyses were assessed for group differences. Treatment-emergent adverse events including blood chemistry metabolites were recorded.

RESULTS

By year 4, supplementation elevated plasma and red blood cell-DHA 4.4- and 3.6-fold, respectively, compared with the placebo group (P < 0.00001). Over the trial duration, no significant differences between DHA and placebo groups were found for vitamin A, vitamin E, platelet aggregation, antioxidant activity, lipoprotein cholesterol, or oxidized LDL levels (all P > 0.14). Adverse events were transient and not considered severe (e.g., gastrointestinal [GI] irritability, blood chemistry alterations). One participant was unable to tolerate persistent GI discomfort.

CONCLUSIONS

Long-term, high-dose DHA supplementation to patients with XLRP was associated with limited safety risks in this 4-year trial. Nevertheless, GI symptoms should be monitored in all patients taking high dose DHA especially those with personal or family history of GI disturbances. (ClinicalTrials.gov number, NCT00100230.).

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.

Fatty acid requirements in preterm infants and their role in health and disease

Challenges remain in optimizing the delivery of fatty acids to attain their nutritional and therapeutic benefits in neonatal health. In this review, knowledge about placental transfer of fatty acids to the developing fetus is summarized, the potential role and mechanisms of fatty acids in enhancing neonatal health and minimizing morbidities is outlined, the unique considerations for fatty acid delivery in the preterm population are defined, and the research questions are proposed that need to be addressed before new standards of care are adopted at the bedside for the provision of critical fatty acids to preterm infants.

The challenge of understanding cerebral white matter injury in the premature infant

White matter injury in the premature infant leads to motor and more commonly behavioral and cognitive problems that are a tremendous burden to society. While there has been much progress in understanding unique vulnerabilities of developing oligodendrocytes over the past 30years, there remain no proven therapies for the premature infant beyond supportive care. The lack of translational progress may be partially explained by the challenge of developing relevant animal models when the etiology remains unclear, as is the case in this disorder. There has been an emphasis on hypoxia-ischemia and infection/inflammation as upstream etiologies, but less consideration of other contributory factors. This review highlights the evolution of white matter pathology in the premature infant, discusses the prevailing proposed etiologies, critically analyzes a sampling of common animal models and provides detailed support for our hypothesis that nutritional and hormonal deprivation may be additional factors playing critical and overlooked roles in white matter pathology in the premature infant.

Meeting the fetal requirement for polyunsaturated fatty acids in pregnancy

PURPOSE OF REVIEW

The aim of this review is to summarize recent evidence on the importance of individual long chain polyunsaturated fatty acid (LCPUFA) to the developing fetus and the maternal dietary requirement for these.

RECENT FINDINGS

Large-scale randomized controlled trials and innovative genetic and stable isotope studies are providing new insights in this field.

SUMMARY

Large randomized controlled trials of LCPUFA supplementation in pregnancy suggest that higher n-3 LCPUFA intake reduces the risk of preterm birth and increases the length of gestation, with secondary effects on birth weight. There is little evidence of an effect on postnatal visual function and cognition, but interpretation is complicated by maternal metabolic adaptations and adipose tissue status in the newborn. The links between polymorphisms in the FADS genes and tissue fatty acid composition suggest that LCPUFA synthesis influences overall availability. Stable isotope studies have also demonstrated the capacity for LCPUFA synthesis in pregnancy, the fact that n-6 synthesis is greater than n-3, metabolic channeling of individual fatty acids to different fates, and selective placental transfer. Studies linking FADS genotype to cognition imply that n-3 LCPUFA synthesis could have an effect on infant cognition, but more large-scale genetic studies are needed.

Plasma phospholipids indicate impaired fatty acid homeostasis in preterm infants

BACKGROUND

During fetal development, docosahexaenoic (DHA) and arachidonic acid (ARA) are particularly enriched in brain phospholipids. After preterm delivery, fetal enrichment of DHA and ARA via placental transfer is replaced by enteral and parenteral nutrition, which is rich in linoleic acid (LA) instead. Specific DHA and ARA enrichment of lipoproteins is reflected by plasma phosphatidylcholine (PC) species, whereas plasma phosphatidylethanolamine (PE) composition reflects hepatic stores.

OBJECTIVE

We profiled PC and PE species in preterm infant plasma, compared with cord and maternal blood, to assess whether current feeding practice meets fetal conditions in these patients.

DESIGN

Preterm infant plasma (N = 171, 23-35 w postmenstrual age (PMA), postnatal day 1-103), cord plasma (N = 194) and maternal serum (N = 121) (both 24-41 w PMA) were collected. After lipid extraction, PC and PE molecular species were analyzed using tandem mass spectrometry.

RESULTS

Phospholipid concentrations were higher in preterm infant than in cord plasma after correction for PMA. This was mainly due to postnatal increases in LA-containing PC and PE, resulting in decreased fractions of their DHA- and ARA-containing counterparts. These changes in preterm infant plasma phospholipids occurred during the time of transition to full enteral feeds (day 0-10 after delivery). Thereafter, the fraction of ARA-containing phospholipids further decreased, whereas that of DHA slowly reincreased but remained at a level 50% of that of PMA-matched cord blood.

CONCLUSIONS

The postnatal increase in LA-PC in preterm infant plasma results in decreased fractions of DHA-PC and ARA-PC. These changes are also reflected by PE molecular composition as an indicator of altered hepatic fatty acid homeostasis. They are presumably caused by inadequately high LA, and low ARA and DHA supply, at a stage of development when ARA-PC and DHA-PC should be high, probably reducing the availability of DHA and ARA to the developing brain and contributing to impaired neurodevelopment of preterm infants.