Long-chain polyunsaturated fatty acids and infant formula

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.

Omega 3 fatty acids on child growth, visual acuity and neurodevelopment

The aim of this review is to evaluate the effects of omega-3 long chain polyunsaturated fatty acids (n-3 LCPUFA) supplementation in pregnant and lactating women and infants during postnatal life, on the visual acuity, psychomotor development, mental performance and growth of infants and children. Eighteen publications (11 sets of randomized control clinical trial [RCTs]) assessed the effects of the n-3 LCPUFA supplementation duringpregnancyon neurodevelopment and growth, in the same subjects at different time points; 4 publications (2 data sets from RCTs) addressed physiological responses to n-3 LCPUFA supplementation duringpregnancy & lactationand 5 publications (3 data sets from RCTs) exclusively duringlactation. Some of these studies showed beneficial effects of docosahexaenoic acid (DHA) supplementation during pregnancy and/or lactation especially on visual acuity outcomes and some on long-term neurodevelopment; a few, showed positive effects on growth. There were also 15 RCTs involving term infants who received infant formula supplemented with DHA, which met our selection criteria. Many of these studies claimed a beneficial effect of such supplementation on visual, neural, or developmental outcomes and no effects on growth. Although new well designed and conducted studies are being published, evidence from RCTs does not demonstrate still a clear and consistent benefit of n-3 LCPUFA supplementation during pregnancy and/or lactation on term infants growth, neurodevelopment and visual acuity. These results should be interpreted with caution due to methodological limitations of the included studies.

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.

Toward optimizing vision and cognition in term infants by dietary docosahexaenoic and arachidonic acid supplementation: a review of randomized controlled trials

The question of whether a dietary supply of docosahexaenoic acid (DHA) and arachidonic acid (ARA) imparts advantages to visual or cognitive development in term infants has been debated for many years. DHA and ARA are present in human milk, and nursing infants consume these fatty acids needed for rapid synthesis of cell membranes, particularly neural cells. The reported mean DHA and ARA levels of human milk worldwide are 0.32% and 0.47% of total fatty acids, respectively. Prior to 2002 in the US, formula-fed infants did not receive these fatty acids and relied solely on endogenous conversion of the dietary essential omega-3 (n-3) and omega-6 (n-6) fatty acids, alpha-linolenic and linoleic acids, to DHA and ARA, respectively. Formula-fed infants were found to have significantly less accretion of DHA in brain cortex after death than breastfed infants. Numerous studies have found positive correlations between blood DHA levels and improvements in cognitive or visual function outcomes of breastfed and formula-fed infants. Results of randomized controlled clinical trials of term formula-fed infants evaluating functional benefits of dietary DHA and ARA have been mixed, likely due to study design heterogeneity. A comparison of visual and cognitive outcomes in these trials suggests that dietary DHA level is particularly relevant. Trials with formulas providing close to the worldwide human milk mean of 0.32% DHA were more likely to yield functional benefits attributable to DHA. We agree with several expert groups in recommending that infants receive at least 0.3% DHA, with at least 0.3% ARA, in infant feedings; in addition, some clinical evidence suggests that an ARA:DHA ratio greater than 1:1 is associated with improved cognitive outcomes.

Effect of supplementing pregnant and lactating mothers with n-3 very-long-chain fatty acids on children's IQ and body mass index at 7 years of age

OBJECTIVES

Arachidonic acid (20:4n-6) and docosahexaenoic acid (22:6n-3) are essential for brain growth and cognitive development. We have reported that supplementing pregnant and lactating women with n-3 very-long-chain polyunsaturated fatty acids promotes higher IQ scores at 4 years of age as compared with maternal supplementation with n-6 polyunsaturated fatty acids. In our present study, the children were examined at 7 years of age with the same cognitive tests as at 4 years of age. We also examined the relation between plasma fatty acid pattern and BMI in children, because an association between arachidonic acid and adipose tissue size has been suggested.

METHODS

The study was randomized and double-blinded. The mothers took 10 mL of cod liver oil or corn oil from week 18 of pregnancy until 3 months after delivery. Their children were tested with the Kaufman Assessment Battery for Children at 7 years of age, and their height and weight were measured.

RESULTS

We did not find any significant differences in scores on the Kaufman Assessment Battery for Children test at 7 years of age between children whose mothers had taken cod liver oil (n = 82) or corn oil (n = 61). We observed, however, that maternal plasma phospholipid concentrations of alpha-linolenic acid (18:3n-3) and docosahexaenoic acid during pregnancy were correlated to sequential processing at 7 years of age. We observed no correlation between fatty acid status at birth or during the first 3 months of life and BMI at 7 years of age.

CONCLUSION

This study suggests that maternal concentration of n-3 very-long-chain polyunsaturated fatty acids during pregnancy might be of importance for later cognitive function, such as sequential processing, although we observed no significant effect of n-3 fatty acid intervention on global IQs. Neonatal fatty acid status had no influence on BMI at 7 years of age.

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. Controversy exists over whether LCPUFA are also essential nutrients in infancy. 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 STRATEGY

Eligible studies were identified by searching MEDLINE (March 2007), EMBASE 1980 - 2007, Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 1, 2007) and CINAHL (December 1982 - March 2007). Abstracts of the Society for Pediatric Research were hand searched from 1980 to 2006 inclusive. Reference lists of published narrative and systematic reviews were also reviewed. No language restrictions were applied.

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

Methodological quality of eligible studies was assessed according to allocation concealment, blinding of intervention, blinding of outcome assessment and completeness of follow up. 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. Continuous data were analysed using weighted mean difference (WMD). There were no categorical outcomes in this review.

MAIN RESULTS

Twenty randomised studies were identified. Fourteen were included (n = 1719) and six excluded. Eleven included studies were of good quality. The main outcomes assessed were visual acuity, neurodevelopmental and physical growth. Visual acuity was measured at various stages throughout the first three years of life by nine studies. Visual evoked potential was used to assess visual acuity in five studies. The remaining four used Teller visual acuity cards. The results were inconsistent. Three studies reported beneficial effect of LCPUFA supplementation on visual acuity while the remaining six did not. Neurodevelopmental outcome was measured at different ages throughout the first two years by eleven studies. Bayley scales of infant development (BSID) was used in eight studies. Only one showed beneficial effect of LCPUFA supplementation on BSID scales. Pooled meta-analysis of the data also did not show any statistically significant benefit of LCPUFA supplementation on either mental or psychomotor developmental index of BSID. One study reported better novelty preference measured by Fagan Infant test at nine months in supplemented infants compared with controls. Another study reported better problem solving at 10 months with supplementation. One study used Brunet and Lezine developmental test to assess the developmental quotient and did not find beneficial effects of LCPUFA supplementation. Physical growth was measured at various ages throughout first three years of life by twelve studies. Some studies reported the actual measurements while some reported the rate of growth over a time period. Some studies z scores. Irrespective of the type of LCPUFA supplementation, duration of supplementation and method of assessment, none of the individual studies found beneficial or harmful effects of LCPUFA supplementation. Meta-analysis of relevant studies also did not show any effect of LCPUFA supplementation on growth of term infants.

AUTHORS' CONCLUSIONS

The results of most of the well conducted RCTS have not shown beneficial effects of LCPUFA supplementation of formula milk on the physical, visual and neurodevelopmental outcomes of infants born at term. Only one group of researchers have shown some beneficial effects on VEP acuity. Two groups of researchers have shown some beneficial effect on mental development. Routine supplementation of milk formula with LCPUFA to improve the physical, neurodevelopmental or visual outcomes of infants born at term can not be recommended based on the current evidence. Further research is needed to see if the beneficial effects demonstrated by Dallas 2005 trial of Birch et al can be replicated in different settings.

Distribution, depletion and recovery of docosahexaenoic acid are region-specific in rat brain

The present study examined: (i) age-induced regional changes in fatty acid composition of brain phospholipids; (ii) alpha-linolenic acid deficiency-induced regional depletion and recovery of DHA in the brain. DHA and arachidonic acid (AA) did not distribute evenly in the brain. In weaning and adult rats, the region with the highest DHA percentage was the cortex whereas the medulla had the lowest DHA percentage. In the aged rats, both the cortex and cerebellum were the regions with the highest DHA percentage whereas in the neonatal rats, the striatum had the greatest percentage of DHA, and the hypothalamus and hippocampus had the least percentage of DHA. Regarding AA, the hippocampus was the region that had the highest percentage whereas the medulla was the region with the lowest percentage except for the neonatal rats, whose cerebellum, hypothalamus, striatum and midbrain had AA percentage lower than hippocampus and cortex. DHA was not proportionally depleted in various regions of brain when the rats were maintained on an n-3-deficient diet for two generations. The results demonstrated that the cortex, hippocampus, striatum, cerebellum and hypothalamus had DHA depleted by >71 %, whereas the midbrain and medulla had only 64 and 57 % DHA depleted, respectively. The most important observation was that the diet reversal for 12 weeks resulted in complete DHA recovery in all regions except for the medulla where the recovery was only 62 %. It was concluded that the location of DHA, n-3 deficiency-induced DHA depletion and reversibility of DHA deficiency across the brain were region-specific.

Supplementation of infant formula with long-chain polyunsaturated fatty acids does not influence the growth of term infants

BACKGROUND

Adequate growth is an important indicator of health and well-being in infants.

OBJECTIVE

Our objective was to determine the effect of supplementing infant formula with long-chain polyunsaturated fatty acids (LCPUFAs) on the growth of term infants.

DESIGN

Using the methodology outlined by the Cochrane Collaboration, we reviewed all known randomized controlled trials that involved LCPUFA supplementation of infant formula fed to term infants. Outcome measures were weight, length, and head circumference. Original data obtained from the investigators of published trials were used. Outcomes were analyzed with fixed-effects or random-effects model meta-analyses and were reported as weighted mean differences with 95% CIs.

RESULTS

We identified 14 eligible trials that had data available for meta-analysis (1846 infants). Trial quality was generally high. Meta-analysis showed no significant effect of LCPUFA supplementation on infant weight, length, or head circumference at any assessment age. Similarly, subgroup analyses showed that supplementation with only n-3 LCPUFAs (no arachidonic acid) had no significant effect on infant weight, length, or head circumference. The source of LCPUFA supplementation (phospholipid or triacylglycerol) also did not significantly affect infant growth.

CONCLUSION

We found no evidence that LCPUFA supplementation of infant formula influences the growth of term infants in either a positive or a negative way.