Prostanoid formation during feeding of a preterm formula with long-chain polyunsaturated fatty acids in healthy preterm infants during the first weeks of life

Polyunsaturated fatty acid supplementation in infancy for the prevention of allergy

BACKGROUND

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

OBJECTIVES

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

SEARCH METHODS

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

Pre- and post-term growth in pre-term infants supplemented with higher-dose DHA: a randomised controlled trial

The effect of the dietary n-3 long-chain PUFA, DHA (22 : 6n-3), on the growth of pre-term infants is controversial. We tested the effect of higher-dose DHA (approximately 1 % dietary fatty acids) on the growth of pre-term infants to 18 months corrected age compared with standard feeding practice (0·2–0·3 % DHA) in a randomised controlled trial. Infants born < 33 weeks gestation (n 657) were randomly allocated to receive breast milk and/or formula with higher DHA or standard DHA according to a concealed schedule stratified for sex and birth-weight ( < 1250 and ≥ 1250 g). The dietary arachidonic acid content of both diets was constant at approximately 0·4 % total fatty acids. The intervention was from day 2 to 5 of life until the infant's expected date of delivery (EDD). Growth was assessed at EDD, and at 4, 12 and 18 months corrected age. There was no effect of higher DHA on weight or head circumference at any age, but infants fed higher DHA were 0·7 cm (95 % CI 0·1, 1·4 cm; P = 0·02) longer at 18 months corrected age. There was an interaction effect between treatment and birth weight strata for weight (P = 0·01) and length (P = 0·04). Higher DHA resulted in increased length in infants born weighing ≥ 1250 g at 4 months corrected age and in both weight and length at 12 and 18 months corrected age. Our data show that DHA up to 1 % total dietary fatty acids does not adversely affect growth.

Effect of long-chain polyunsaturated fatty acid supplementation of preterm infants on disease risk and neurodevelopment: a systematic review of randomized controlled trials

BACKGROUND

Supplementation of preterm formulas with long-chain polyunsaturated fatty acids (LCPUFAs) is based on their effectiveness to increase blood status and improve visual outcomes. Dispute remains over their efficacy on global development.

OBJECTIVE

The objective was to compare the effects of LCPUFA-supplemented with those of control formulas on neurodevelopment and diseases associated with prematurity.

DESIGN

We systematically reviewed randomized controlled trials involving preterm infants that tested LCPUFA-supplemented formulas. The weighted mean differences (WMDs) in neurodevelopmental scores and relative risk (RR) of disease were calculated to compare infants fed LCPUFA-supplemented formula with those fed control formula.

RESULTS

No clear differences in Bayley Scales of Infant Development (BSID) scores were observed between groups. Mental development of LCPUFA-supplemented infants was 3.4 points higher than that of control infants with BSID version II (WMD: 3.44; 95% CI: 0.56, 6.31; P = 0.02; n = 879), although it was driven by 2 trials with large effect sizes and wide CIs. Psychomotor development was lower in supplemented infants tested with BSID version I (WMD: -7.99; 95% CI: -14.00, -1.99; P = 0.009; n = 87); however, it was limited by small sample sizes. No differences in the RR of sepsis (1.08; 95% CI: 0.79, 1.46; P = 0.63; n = 1333) or in the RR of necrotizing enterocolitis (1.13; 95% CI: 0.62, 2.04; P = 0.69; n = 1333) were found. Similarly, the risks of retinopathy of prematurity, intraventricular hemorrhage, and bronchopulmonary dysplasia were not different between groups, but data were limited by small sample sizes and trials with an increased risk of bias.

CONCLUSIONS

LCPUFA-supplemented formula does not alter the risk of NEC or sepsis. Further work is needed to determine the extent of benefit of LCPUFA-supplemented formula on the mental development of preterm infants.

Low-dose aspirin in pregnancy: maternal and neonatal aspirin concentrations and neonatal prostanoid formation

OBJECTIVE

To evaluate maternal and neonatal plasma concentrations of acetylsalicylic acid and salicylic acid and the neonatal endogenous prostanoid formation during low-dose aspirin prophylaxis (LDA; 100 mg daily) in pregnant women.

METHODS

Concentrations of acetylsalicylic acid and salicylic acid in maternal plasma after at least 4 weeks of LDA (n = 14) and in umbilical cord plasma of newborns after maternal LDA (n = 7) were determined by gas chromatography-mass spectrometry. Platelet and renal formation of thromboxane A2 and the formation of prostaglandin E2 and prostacyclin were evaluated in vivo by quantification of index metabolites in plasma and urine by gas chromatography-mass spectrometry in neonates after maternal LDA (n = 14) and in a control group.

RESULTS

In the pregnant women, acetylsalicylic acid and salicylic acid concentrations rapidly increased after ingestion of LDA. Acetylsalicylic acid was completely eliminated within 4 hours, whereas salicylic acid was detected with low concentrations at 18 and 21 hours after dosing. In the neonates, acetylsalicylic acid was not detected. Salicylic acid was detected in 1 infant only. Platelet thromboxane A2 formation in the newborn infants was significantly suppressed but recovered within 2 to 3 days after discontinuation of LDA. Renal thromboxane A2 formation and the formation of prostaglandin E2 and prostacyclin were not affected by LDA.

CONCLUSION

In pregnant women who are treated with LDA, acetylsalicylic acid is not completely inactivated in the portal circulation but reaches the uteroplacental circulation and exerts antiplatelet effects in the fetus and newborn.

Role of renal PGE2 in the adaptation from foetal to extrauterine life in term and preterm infants

Urinary PGE(2) concentrations were assayed using a new EIA method, in 16 preterm and 18 term neonates at birth and 3 days later, since there is evidence that PGE(2) in urine are likely to reflect their renal generation and then could be correlated with kidney maturation or renal problems. PGE(2) concentrations were not different at birth (1.50+/-1.12 vs 1.56+/-1.94 ng/day), while resulted significantly higher in preterms, compared to terms, three days after birth (2.22+/-1.23 vs 1.39+/-0.79 ng/day). This increase in daily PGE(2) excretion observed only in preterm neonates could be due to an increased renal biosynthesis as a mechanism of compensatory response to prevent further decrements in renal plasma flow, since prostanoids play an important role in protecting the immature kidney from high levels of angiotensin II. Otherwise, the passive reabsorption of PGE(2) along the distal nephron could be altered because of kidney immaturity. The measurement of PGE(2) in urine of neonates, particularly prematures, could be useful to provide a better understanding of the homeostatic function of the kidney in the phase of adaptation to extra-uterine life.

Nutrient requirements for preterm infant formulas

Achieving appropriate growth and nutrient accretion of preterm and low birth weight (LBW) infants is often difficult during hospitalization because of metabolic and gastrointestinal immaturity and other complicating medical conditions. Advances in the care of preterm-LBW infants, including improved nutrition, have reduced mortality rates for these infants from 9.6 to 6.2% from 1983 to 1997. The Food and Drug Administration (FDA) has responsibility for ensuring the safety and nutritional quality of infant formulas based on current scientific knowledge. Consequently, under FDA contract, an ad hoc Expert Panel was convened by the Life Sciences Research Office of the American Society for Nutritional Sciences to make recommendations for the nutrient content of formulas for preterm-LBW infants based on current scientific knowledge and expert opinion. Recommendations were developed from different criteria than that used for recommendations for term infant formula. To ensure nutrient adequacy, the Panel considered intrauterine accretion rate, organ development, factorial estimates of requirements, nutrient interactions and supplemental feeding studies. Consideration was also given to long-term developmental outcome. Some recommendations were based on current use in domestic preterm formula. Included were recommendations for nutrients not required in formula for term infants such as lactose and arginine. Recommendations, examples, and sample calculations were based on a 1000 g preterm infant consuming 120 kcal/kg and 150 mL/d of an 810 kcal/L formula. A summary of recommendations for energy and 45 nutrient components of enteral formulas for preterm-LBW infants are presented. Recommendations for five nutrient:nutrient ratios are also presented. In addition, critical areas for future research on the nutritional requirements specific for preterm-LBW infants are identified.

Randomized trials with polyunsaturated fatty acid interventions in preterm and term infants: functional and clinical outcomes

The role of polyunsaturated fatty acids (PUFA) in infant nutrition has now been well studied through many randomized controlled trials (RCT) that provide us with high-quality evidence, particularly in relation to efficacy. As a result of a systematic search of the literature for RCT of supplementation of formulas of term and preterm infants with long-chain polyunsaturated fatty acids (LC-PUFA), we have identified 21 studies that have physiological responses or growth as outcomes. There have been 11 RCT involving preterm infants, and many of these claim a beneficial effect on visual, neural, or developmental outcomes. There are some reports of negative effects on growth in relation to the addition of n-3 LC-PUFA to preterm formulas but not when AA is added with n-3 LC-PUFA. Small studies have shown no differences in prostanoid formation or peroxidative stress between n-3 LC-PUFA-supplemented and unsupplemented infants. There have been 10 RCT involving term infants; whereas some studies report an effect on visual/neural/developmental outcomes, an equal number report no effect. There have been no reports of negative effects of n-3 LC-PUFA on growth in term infants. In summary, there appear to be few safety concerns relating to the use of LC-PUFA in infant nutrition. The potential medium- and long-term effects of including these compounds in the early diet of infants remain to be assessed.

The role of polyunsaturated fatty acids in term and preterm infants and breastfeeding mothers

DHA and AA, which are components of breast milk but not infant formulas marketed in the United States and some other countries, are important components of the brain, and DHA is a major component of the retina. Also, many studies have demonstrated advantages of breastfeeding versus formula-feeding on subsequent cognitive and visual function; however, available data are insufficient to justify the conclusion that the presence of DHA and AA in breast milk is partially or soley responsible for the apparent advantages of breastfeeding. On the other hand, many studies of DHA (and AA)-supplemented versus unsupplemented formulas have shown clear advantages of the supplemented formulas on visual acuity at 2 and 4 months of age or neurodevelopmental status at 12 to 18 months of age. Although one logically may assume that these early effects may have long-term effects, this assumption is not warranted by the available data. One of the major problems is the difficulty of assessing visual and cognitive function of infants. Scores on standard neurodevelopmental tests at 1 year of age, for example, are only weakly correlated with performance at school age (when more definitive assessments are possible), and little is known about the predictability of later visual function from behavioral or electrophysiologic assessments of visual function early in life. Even prematurely born infants can synthesize DHA and AA and other omega-3 and omega-6 LC-PUFAs from the dietary EFAs, LA and ALA. Nonetheless, plasma, erythrocyte and brain lipid levels of DHA are lower in infants whose diets do not contain DHA. Whether more optimal intakes of ALA result in higher plasma and tissue levels of this FA is unclear. The breast-milk content of LC-PUFAs is not regulated by the mammary gland but, rather, reflects the concentrations of LC-PUFAs in maternal plasma lipids that, in turn, are dependent on maternal diet and, probably, maternal activities of the desaturases and elongases involved in converting dietary LA and ALA to LC-PUFAs. This occurrence suggests that some infants receive sufficient LC-PUFA to support normal rates of deposition, whereas others may not. Also, some infants probably can synthesize additional LC-PUFAs from the LA and ALA contents of human milk. Thus, depending on maternal diet and maternal and infant desaturase and elongase activities, some breastfed infants may receive less than adequate LC-PUFAs to support normal rates of deposition. Clearly, the role of LC-PUFAs in infant development is not a simple issue. Also, no foolproof method exists to ensure an adequate but not excessive intake. Thus, because some evidence shows that dietary LC-PUFA (DHA, AA, or both) as components of breast milk or formula confers at least transient developmental benefits, supplementation of infant formulas with LC-PUFAs is supportable provided that the supplements used are safe. The safety of all available supplements is unknown; however, some trials reveal few reasons for major concerns about the safety of single-cell oils, low-EPA fish oil, or egg-yolk phospholipid or triglyceride fractions.

Effect of preterm formula with and without long-chain polyunsaturated fatty acids on the urinary excretion of F2-isoprostanes and 8-epi-prostaglandin F2alpha

BACKGROUND

The objective of this study was to evaluate the effect of conventional and long-chain polyunsaturated fatty acids (LCP)-enriched preterm formula on the endogenous formation of F2-isoprostanes and 8-epi-prostaglandin (PG) F2alpha as possible markers of lipid peroxidation in preterm infants during their first weeks of life.

METHODS

In a prospective, randomized, double-blind study, infants received either formula enriched with LCP (n = 8), standard preterm formula (n = 7), or (expressed) breast milk (n = 8). Urine was sampled at study entry and after the study period of 3 weeks. The formation of F2-isoprostanes and 8-epi-PGF2alpha was evaluated by measuring the urinary excretion by gas chromatography-mass spectrometry.

RESULTS

No differences in the urinary excretion of F2-isoprostanes and 8-epi-PGF2alpha were observed at the end of the study period.

CONCLUSIONS

This result suggests that supplementation of a preterm formula with LCP for a period of 3 weeks does not stimulate lipid peroxidation in preterm infants.

Biological effects and safety issues related to long-chain polyunsaturated fatty acids in infants

The purpose of this workshop at the American Oil Chemists' Society Symposium, "PUFA in Infant Nutrition: Consensus and Controversies," was to enumerate the safety issues raised by the prospect of supplementing infant formulas with long-chain polyunsaturated fatty acids (LC-PUFA), to evaluate the evidence that these concerns are problematical, or theoretically problematical, and to identify the safety issues most in need of resolution. This was approached by reviewing briefly the known biological effects of LC-PUFA and how these effects might give rise to concerns about safety of LC-PUFA as components of infant formulas. Some of these issues were then discussed in more detail by invited participants, all of whom had submitted abstracts concerning the issue discussed. The pertinent aspects of all issues discussed during the workshop are summarized. In addition, since the symposium was held over 2 yr ago, an addendum summarizing additional data reported since the symposium that either support or refute issues discussed during the workshop also is included.