Visual acuity and blood lipids in term infants fed human milk or formulae

A Scoping Review of Clinical Studies in Infants Fed Formulas Containing Palm Oil or Palm Olein and Sn-2 Palmitate

BACKGROUND

Palmitic acid (PA; 16:0) is added to infant formula in the form of palm oil/palm olein (PO/POL) and stereospecific numbered-2 palmitate (SN2). Several studies have examined the effects of PO/POL and or SN2 in formulas on health outcomes, mainly growth, digestion, and absorption of nutrients. However, the roles of PA, PO/POL, and SN2 on neurodevelopment remains unknown.

OBJECTIVES

The objective of this scoping review was to map out studies in infants fed formula with PO/POL or SN2 to identify current knowledge on the role of PA in infant nutrition, specifically neurodevelopment.

METHODS

Data sources, including Medline, Embase, CAB Abstracts, and the Cochrane Database, were searched. Eligible articles were randomized controlled trials (RCTs) and observational studies examining outcomes in term singleton infants fed formula containing PO/POL or SN2. Studies examining preterm infants or infants with infections, mixed-feeding interventions, or outcomes not concerned with PO/POL or SN2 were excluded. Screening and data extraction were performed by 2 independent reviewers, and results were charted into 10 outcome categories.

RESULTS

We identified 28 RCTs and 2 observational studies. Only 1 RCT examined a neurodevelopmental outcome, reporting infants fed SN2 formula had higher fine motor skill scores compared to those fed a vegetable oil formula with a lower amount of SN2; however, only after adjustment for maternal education and at an earlier, but not a later time point. Anthropometric measures do not appear to be influenced by PO/POL or SN2 within formulas. Alternatively, it was reported that infants fed PO/POL within formulas had a decreased absorption of calcium, total fat, and PA compared to those fed vegetable oil formulas. However, studies were heterogenous, making it difficult to isolate the effects of PO/POL or SN2 in formulas.

CONCLUSIONS

Our review reiterates the need for future studies to address the effects of PO/POL and SN2 on neurodevelopment in infants. This study is registered at Open Science Framework as osf.io/697he.

The Importance of Marine Omega-3s for Brain Development and the Prevention and Treatment of Behavior, Mood, and Other Brain Disorders

Most of the global population is deficient in long-chain marine omega-3s. In particular, docosahexaenoic acid (DHA), a long-chain omega-3 fatty acid, is important for brain and eye development. Additionally, DHA plays a significant role in mental health throughout early childhood and even into adulthood. In the brain, DHA is important for cellular membrane fluidity, function and neurotransmitter release. Evidence indicates that a low intake of marine omega-3s increases the risk for numerous mental health issues, including Attention Deficit Hyperactivity Disorder (ADHD), autism, bipolar disorder, depression and suicidal ideation. Studies giving supplemental marine omega-3s have shown promise for improving numerous mental health conditions. This paper will review the evidence surrounding marine omega-3s and mental health conditions.

Human milk fatty acid profile across lactational stages after term and preterm delivery: A pooled data analysis

BACKGROUND

Lipids in human milk (HM) provide the majority of energy for developing infants, as well as crucial essential fatty acids (FA). The FA composition of HM is highly variable and influenced by multiple factors. We sought to increase understanding of the variation in HMFA profiles and their development over the course of lactation, and after term and preterm delivery, using a pooled data analysis.

OBJECTIVE

To review the literature and perform a pooled data analysis to qualitatively describe an extensive FA profile (36 FAs) in term and preterm colostrum, transitional - and mature milk up to 60 days postpartum.

DESIGN

A Medline search was conducted for HMFA profile data following term or preterm delivery. The search was confined to English language papers published between January 1980 and August 2018. Studies reporting original data, extensive FA profiles in HM from healthy mothers were included. Weighted least squares (WLS) means were calculated from the pooled data using random or fixed effect models.

RESULTS

Our pooled data analysis included data from 55 studies worldwide, for a total of 4374 term milk samples and 1017 preterm milk samples, providing WLS means for 36 FAs. Patterns in both term and preterm milk were apparent throughout lactation for some FAs: The most abundant FAs (palmitic, linoleic and oleic acid) remained stable over time, whereas several long-chain polyunsaturated FAs (including ARA and DHA) seemed to decrease and short- and medium-chain FAs increased over time.

CONCLUSIONS

High heterogeneity between individual studies was observed for the reported levels of some FAs, whereas other FAs were remarkably consistent between studies. Our pooled data suggests that specific FA categories fluctuate according to distinct patterns over the course of lactation; many of these patterns are comparable between term and preterm milk.

The Kansas University DHA Outcomes Study (KUDOS) clinical trial: long-term behavioral follow-up of the effects of prenatal DHA supplementation

BACKGROUND

Docosahexaenoic acid (DHA) is a long-chain polyunsaturated fatty acid that has been linked to improved vision and cognition in postnatal feeding studies and has been consistently associated with reduction of early preterm birth in prenatal supplementation trials. This is a report of the first long-term follow-up of infants from mothers receiving prenatal DHA supplementation in a US cohort.

OBJECTIVE

Our objective was to evaluate the efficacy of the prenatal supplementation on both global and granular longitudinal assessments of cognitive and behavioral development.

METHODS

In a randomized double-blind clinical trial, mothers received either 600 mg/d of DHA or a placebo beginning at 14.5 weeks of gestation and capsules were provided until delivery. Children from those pregnancies were followed by cognitive and behavioral assessments administered from 10 mo through 6 y of age. From 301 mothers in the initial study, ∼200 infants completed the longitudinal schedule.

RESULTS

Although this intervention had been shown to reduce high-risk pregnancies and improve visual attention in infants during the first year, only a few positive long-term effects of prenatal DHA supplementation emerged from analyses of this follow-up. Increases in maternal blood DHA during pregnancy were related to verbal and full scale intelligence quotient (IQ) scores at 5 and 6 y, but these effects disappeared after controlling for SES. Maternal blood DHA concentrations at delivery were unrelated to outcomes, although maternal DHA at enrollment was related to productive vocabulary at 18 mo.

CONCLUSIONS

Although prenatal DHA supplementation substantially reduced early preterm birth and improved visual attention in infancy in this sample, no consistent long-term benefits were observed into childhood. Increases in maternal blood DHA concentration in pregnancy were related to higher IQs but this effect was confounded with SES and disappeared when SES was statistically controlled. This trial was registered at http://www.clinicaltrials.gov as NCT00266825 and NCT02487771.

Palm Oil and Beta-palmitate in Infant Formula: A Position Paper by the European Society for Paediatric Gastroenterology, Hepatology, and Nutrition (ESPGHAN) Committee on Nutrition

BACKGROUND

Palm oil (PO) is used in infant formulas in order to achieve palmitic acid (PA) levels similar to those in human milk. PA in PO is esterified predominantly at the SN-1,3 position of triacylglycerol (TAG), and infant formulas are now available in which a greater proportion of PA is in the SN-2 position (typical configuration in human milk). As there are some concerns about the use of PO, we aimed to review literature on health effects of PO and SN-2-palmitate in infant formulas.

METHODS

PubMed and Cochrane Database of Systematic Reviews were systematically searched for relevant studies on possible beneficial effects or harms of either PO or SN-2-palmitate in infant formula on various health outcomes.

RESULTS

We identified 12 relevant studies using PO and 21 studies using SN-2-palmitate. Published studies have variable methodology, subject characteristics, and some are underpowered for the key outcomes. PO is associated with harder stools and SN-2-palmitate use may lead to softer stool consistency. Bone effects seem to be short-lasting. For some outcomes (infant colic, faecal microbiota, lipid metabolism), the number of studies is very limited and summary evidence inconclusive. Growth of infants is not influenced. There are no studies published on the effect on markers of later diseases.

CONCLUSIONS

There is insufficient evidence to suggest that PO should be avoided as a source of fat in infant formulas for health reasons. Inclusion of high SN-2-palmitate fat blend in infant formulas may have short-term effects on stool consistency but cannot be considered essential.

Impact of palm olein in infant formulas on stool consistency and frequency: a meta-analysis of randomized clinical trials

Background: Meta-analysis studies have documented that palm olein (PALM) predominant formulas reduce calcium and fat absorption, and bone mineralization in infants, but none have been documented for stool consistency and frequency.

Objective: The study objective was to conduct a meta-analysis of published randomized clinical trials (RCTs) on the effect of PALM-based formulas on stool consistency and frequency in infants.

Design: A literature search was conducted in BIOSIS Previews®, Embase®, Embase® Alert, MEDLINE® and Cochrane databases. PALM-based RCTs with available stool outcomes were selected and meta-analyzed. Mean rank stool consistency (MRSC, primary outcome) and stool frequency (secondary outcome) were compared between infants fed PALM-based and PALM-free formulas (NoPALM), using random effects model.

Results: Nine out of identified16 studies were meta-analyzed. The mean MRSC (scale of 1 = watery to 5 = hard) in the NoPALM-fed infants was lower (softer stools) compared to the PALM-fed infants (mean difference ‒0.355, 95% Confidence Interval [CI] of ‒0.472 to ‒0.239, p < 0.001). Difference for stool frequency was not significant (p = 0.613).

Conclusion: Meta-analysis of RCTs indicated that NoPALM-fed infants have significantly softer stools but similar stool frequencies versus PALM-fed infants, despite differences in study types and design. Future meta-analysis could benefit from including comparison with human milk-fed infants.

Retina and omega-3

Over the last decade, several epidemiological studies based on food frequency questionnaires suggest that omega-3 polyunsaturated fatty acids could have a protective role in reducing the onset and progression of retinal diseases. The retina has a high concentration of omega-3, particularly DHA, which optimizes fluidity of photoreceptor membranes, retinal integrity, and visual function. Furthermore, many studies demonstrated that DHA has a protective, for example antiapoptotic, role in the retina. From a nutritional point of view, it is known that western populations, particularly aged individuals, have a higher than optimal omega-6/omega-3 ratio and should enrich their diet with more fish consumption or have DHA supplementation. This paper underscores the potential beneficial effect of omega-3 fatty acids on retinal diseases.

Long-chain polyunsaturated fatty acid supplementation in infancy reduces heart rate and positively affects distribution of attention

A double-blind, randomized, controlled, parallel-group prospective trial was conducted to determine whether a dose-response existed for four different levels of docosahexaenoic acid (DHA) supplementation on the cognitive performance of infants. A total of 122 term infants were fed one of four different formulas varying in their DHA composition (0.00, 0.32, 0.64, and 0.96% of total fatty acids as DHA) from birth to 12 mo. The three DHA-supplemented formulas also contained 0.64% of total fatty acids as arachidonic acid (ARA, 20:4n-6). Infants were tested at 4, 6, and 9 mo of age on a visual habituation protocol that yielded both behavioral and psychophysiological indices of attention. Infants in all DHA+ARA-supplemented conditions had lower heart rates than those in the unsupplemented condition; there was no dose-response for this effect. The distribution of time that infants spent in different phases of attention (a cognitive index derived from the convergence of behavioral and cardiac responses) varied as a function of dosage. Infants supplemented at the two lower DHA doses spent proportionately more time engaged in active stimulus processing than infants fed the unsupplemented formula, whereas infants fed the highest dose were intermediate and did not differ from any other group.

The DIAMOND (DHA Intake And Measurement Of Neural Development) Study: a double-masked, randomized controlled clinical trial of the maturation of infant visual acuity as a function of the dietary level of docosahexaenoic acid

BACKGROUND

The range of human milk docosahexaenoic acid (DHA) concentrations worldwide is much broader than the range explored in randomized clinical trials to date.

OBJECTIVE

The primary objective was to determine the effect of 4 amounts of DHA supplementation on the visual acuity of formula-fed infants at 12 mo of age. Secondary objectives were to evaluate visual acuity maturation, red blood cell fatty acids, tolerance, anthropometric measures, and adverse events.

DESIGN

This double-masked, randomized trial was conducted at 2 sites (Dallas and Kansas City). Three hundred forty-three healthy, term, formula-fed infants were enrolled at 1-9 d of age and were randomly assigned to be fed 1 of the following 4 infant formulas containing equivalent nutrient amounts, except for long-chain polyunsaturated fatty acids: control (0% DHA), 0.32% DHA, 0.64% DHA, or 0.96% DHA; DHA-supplemented formulas also provided 0.64% arachidonic acid. Visual acuity was measured by visual evoked potentials in 244 infants who completed the 12-mo primary outcome examination.

RESULTS

Infants fed control formula had significantly poorer visual evoked potential visual acuity at 12 mo of age than did infants who received any of the DHA-supplemented formulas (P < 0.001). There were no significant differences in visual evoked potential visual acuity between the 3 amounts of DHA supplementation for either site at any age tested.

CONCLUSIONS

DHA supplementation of infant formula at 0.32% of total fatty acids improves visual acuity. Higher amounts of DHA supplementation were not associated with additional improvement of visual acuity. This trial was registered at clinicaltrials.gov as NCT00753818.

Three randomized controlled trials of early long-chain polyunsaturated Fatty Acid supplementation on means-end problem solving in 9-month-olds

This study examines whether feeding infants formula supplemented with long-chain polyunsaturated fatty acids (LCPUFA) improves cognitive function of 9-month-olds. Participants included 229 infants from 3 randomized controlled trials. Children received either formula supplemented with docosahexaenoic acid and arachidonic acid, or a control formula beginning at 1-5 days (12-month feeding study), or following 6 weeks (6-week-weaning study) or 4-6 months of breastfeeding (4-to 6-month weaning study). Infants were assessed with a 2-step problem solving task. In the 12-month feeding and 6-week weaning studies, supplemented children had more intentional solutions (successful task completions) and higher intention scores (goal-directed behaviors) than controls. These results suggest that LCPUFA supplementation improves means-end problem solving.

Effect of breastfeeding and sociodemographic factors on visual outcome in childhood and adolescence

BACKGROUND

It has been suggested that early life factors, including breastfeeding and birth weight, program childhood myopia.

OBJECTIVE

We examined the relation of reduced unaided vision (indicative of myopia) in childhood and adolescence with infant feeding, parental education, maternal age at birth, birth weight, sex, birth order, and socioeconomic status.

DESIGN

Three British cohorts recruited infants born in 1946 (n = 5362), 1958 (n = 18,558), and 1970 (n = 16,567). Adjusted odds ratios (ORs) for unaided vision of 6/12 or worse at ages 10-11 and 15-16 y from each cohort were pooled by using fixed-effects meta-analyses.

RESULTS

The prevalence of reduced vision ranged from 4.4% to 6.5% at 10-11 y and from 9.4% to 11.4% at 16 y, with marginally higher levels in later cohorts. Breastfeeding declined across successive cohorts (65%, 43%, and 22% in those breastfed for >1 mo, respectively). Pooled ORs showed no associations between infant feeding and vision after adjustment at either age. Parental education (OR: 1.48, high versus low education; 95% CI: 1.23, 1.79), maternal age (OR: 1.10, per 5-y increase; 95% CI: 1.04, 1.17), birth weight (OR: 0.85, per 1-kg rise; 95% CI: 0.76, 0.95), number of older siblings (OR: 0.89, per older sibling; 95% CI: 0.83, 0.94), and sex (OR: 1.10, girls versus boys; 95% CI: 0.98, 1.23) were related to adverse visual outcome in childhood. Stronger associations were observed in adolescence, except that the association with birth weight was null.

CONCLUSIONS

Infant feeding does not appear to influence visual development. Consistent associations of reduced vision with parental education, sex, maternal age, and birth order suggest that other environmental factors are important for visual development and myopia in early life.

Docosahexaenoic and arachidonic acid concentrations in human breast milk worldwide

Concentrations of the long-chain polyunsaturated fatty acids (LCPUFAs) docosahexaenoic acid (DHA, 22:6n-3) and arachidonic acid (AA, 20:4n-6) in human breast milk are important indicators of infant formula DHA and AA concentrations, and recent evidence suggests that neural maturation of breastfed infants is linked to breast-milk LCPUFA concentrations. We report a descriptive meta-analysis that considered 106 studies of human breast milk culled to include only studies that used modern analysis methods capable of making accurate estimates of fatty acid (FA) profiles and criteria related to the completeness of reporting. The final analysis included 65 studies of 2474 women. The mean (+/-SD) concentration of DHA in breast milk (by wt) is 0.32 +/- 0.22% (range: 0.06-1.4%) and that of AA is 0.47 +/- 0.13% (range: 0.24-1.0%), which indicates that the DHA concentration in breast milk is lower than and more variable than that of AA. The highest DHA concentrations were primarily in coastal populations and were associated with marine food consumption. The correlation between breast-milk DHA and AA concentrations was significant but low (r = 0.25, P = 0.02), which indicates that the mean ratio of DHA to AA in regional breast milk varies widely. This comprehensive analysis of breast-milk DHA and AA indicates a broad range of these nutrients worldwide and serves as a guide for infant feeding.

Fatty acid composition of white adipose tissue and breast milk of Mauritian and French mothers and erythrocyte phospholipids of their full-term breast-fed infants

The fatty acid compositions of white adipose tissue, colostrum and mature milk triacylglycerols from Mauritian (n 13) and French (n 15) women were analysed and compared in order to highlight cultural differences in dietary intakes and their influence on milk fatty acid composition. Erythrocyte phosphatidylethanolamine and phosphatidylcholine fatty acid compositions were also investigated in their term infants, breast-fed over a period of 6 weeks. Fatty acid composition (g/100 g) of all samples was determined by GLC and anthropometric measurements were assessed in the two populations at birth and on day 42. Comparisons of white adipose tissue fatty acid compositions demonstrated lower levels of saturated (23·64 (se 1·54) v. 29·75 (se 0·67), P < 0·01) and monounsaturated (39·44 (se 1·27) v. 54·84 (se 0·75), P < 0·001) fatty acids and higher levels of polyunsaturated fatty acids (n−6 series: 32·47 (se 1·31) v. 14·32 (se 0·47), P < 0·001 and n−3 series: 2·87 (se 0·49) v. 0·80 (se 0·07), P < 0·01) in Mauritian than in French samples respectively. Accordingly, milk fat of the Mauritian women contained higher levels of parent essential fatty acids and their longer-chain derivatives than did milk fat from French women. Higher levels of parent essential fatty acids but lower levels of long-chain polyunsaturated fatty acids were found in erythrocyte phospholipids of Mauritian infants compared with French infants. Infants' erythrocyte arachidonate and docosahexaenoate contents did not correlate with any anthropometric variables at birth or at day 42, neither did they correlate with anthropometric variation over the study period. Our results suggest the lack of a simple relationship between the amount of long-chain polyunsaturated fatty acids in human milk and their accretion in the erythrocyte phospholipids of breast-fed infants when provided concomitantly with high levels of both linoleic and α-linolenic acids in ratios which fall within recommended ranges.

Infant nutrition and stereoacuity at age 4-6 y

BACKGROUND

Breastfeeding has been reported to benefit visual development in children. A higher concentration of docosahexaneoic acid (DHA) in breast milk than in formula has been proposed as one explanation for this association and as a rationale for adding DHA to infant formula, but few long-term data support this possibility.

OBJECTIVE

The objectives of the study were, first, to test the hypothesis that breastfeeding benefits stereoscopic visual maturation and, second, if that benefit is shown, to ascertain whether it is mediated by the dietary intake of DHA.

DESIGN

Stereoacuity was measured by using the random dot E test (primary outcome), and visual acuity was measured by using the Sonksen-Silver acuity system (secondary outcome) in previously breastfed (n = 78) or formula-fed (n = 184) children aged 4-6 y who had been followed prospectively from birth. In the formula-fed group, children were randomly assigned to receive formula with either DHA or arachidonic acid (n = 94) or a control formula (n = 90) for the first 6 mo.

RESULTS

Breastfed children had a significantly (P = 0.001) greater likelihood of foveal stereoacuity (high-grade or < 100 s/arc) than did formula-fed children (odds ratio: 2.5; 95% CI: 1.4, 4.5) independent of potential confounding (P = 0.005). Stereoacuity did not differ significantly between children randomly assigned to DHA-supplemented or control formula. None of the groups differed in Sonksen-Silver visual acuity.

CONCLUSIONS

These findings support the hypothesis that breastfeeding benefits long-term stereoscopic development. An effect of DHA cannot be excluded, but the lack of difference in stereoacuity between infants randomly assigned to DHA-containing and those assigned to control formula raises the hypothesis that factors in breast milk other than DHA account for the observed benefits.

Dietary PUFA for preterm and term infants: review of clinical studies

Human milk contains n-3 and n-6 LCPUFA (long chain polyunsaturated fatty acids), which are absent from many infant formulas. During neonatal life, there is a rapid accretion of AA (arachidonic acid) and DHA (docosahexaenoic acid) in infant brain, DHA in retina and of AA in the whole body. The DHA status of breast-fed infants is higher than that of formula-fed infants when formulas do not contain LCPUFA. Studies report that visual acuity of breast-fed infants is better than that of formula-fed infants, but other studies do not find a difference. Cognitive development of breast-fed infants is generally better, but many sociocultural confounding factors may also contribute to these differences. The effect of dietary LCPUFA on FA status, immune function, visual, cognitive, and motor functions has been evaluated in preterm and term infants. Plasma and RBC FA status of infants fed formulas supplemented with both n-3 and n-6 LCPUFA was closer to the status of breast-fed infants than to that of infants fed formulas containing no LCPUFA. Adding n-3 LCPUFA to preterm-infant formulas led to initial beneficial effects on visual acuity. Few data are available on cognitive function, but it seems that in preterm infants, feeding n-3 LCPUFA improved visual attention and cognitive development compared with infants receiving no LCPUFA. Term infants need an exogenous supply of AA and DHA to achieve similar accretion of fatty acid in plasma and RBC (red blood cell) in comparison to breast-fed infants. Fewer than half of all studies have found beneficial effects of LCPUFA on visual, mental, or psychomotor functions. Improved developmental scores at 18 mo of age have been reported for infants fed both AA and DHA. Growth, body weight, and anthropometrics of preterm and term infants fed formulas providing both n-3 and n-6 LCPUFA fatty acids is similar in most studies to that of infants fed formulas containing no LCPUFA. A larger double-blind multicenter randomized study has recently demonstrated improved growth and developmental scores in a long-term feeding study of preterm infants. Collectively, the body of literature suggests that LCPUFA is important to the growth and development of infants. Thus, for preterm infants we recommend LCPUFA intakes in the range provided by feeding of human milk typical of mothers in Western countries. This range can be achieved by a combination of AA and DHA, providing an AA to DHA ratio of approximately 1.5 and a DHA content of as much as 0.4%. Preterm infants may benefit from slightly higher levels of these fatty acids than term infants. In long-term studies, feeding more than 0.2% DHA and 0.3% AA improved the status of these fatty acids for many weeks after DHA; AA was no longer present in the formula, enabling a DHA and AA status more similar to that of infants fed human milk. The addition of LCPUFA in infant formulas for term infants, with appropriate regard for quantitative and qualitative qualities, is safe and will enable the formula-fed infant to achieve the same blood LCPUFA status as that of the breast-fed infant.

The role of essential fatty acids in development

The presence of docosahexaenoic acid (DHA) and arachidonic acid (ARA) in human milk but not in infant formula, coupled with lower plasma and brain lipid contents of DHA in formula-fed than in breast-fed infants and reports of higher IQ in individuals who were breast-fed versus formula-fed as infants, suggest that exogenous DHA (and ARA) may be essential for optimal development. Thus, since 1990, several studies have examined the impact of formulas containing DHA or DHA plus ARA on visual function and neurodevelopmental outcome. Some of these studies have shown benefits but others have not. These results leave largely unanswered the question of whether these fatty acids are beneficial for either the term or preterm infant. However, evidence that preterm infants might benefit is somewhat more convincing than that for term infants. Despite the limited evidence for efficacy, formulas supplemented with DHA and ARA are now available and appear to be safe.

The effect of α-linolenic acid and linoleic acid on the growth and development of formula-fed infants: A systematic review and meta-analysis of randomized controlled trials

This systematic review and meta-analysis aimed to evaluate the effect of modifying 18-carbon PUFA [18-C PUFA: alpha-linolenic acid (ALA, 18:3n-3) and linoleic acid (LA, 18:2n-6)] in the diets of term and preterm infants on DHA (22:6n-3) status, growth, and developmental outcomes. Only randomized controlled trials (RCT) involving formula-fed term and preterm infants, in which the 18-C PUFA composition of the formula was changed and growth or developmental outcomes were measured, were included. Differences were presented as control (standard formula) and treatment (18-C PUFA-supplemented formula). Primary analyses for term infants were 4 and 12 mon and for preterm infants 37-42 and 57 wk postmenstrual age. Five RCT involving term infants and three RCT involving preterm infants were included in the systematic review. Infants fed ALA-supplemented formula had significantly higher plasma and erythrocyte phospholipid DHA levels than control infants. There was no effect of ALA supplementation on the growth of preterm infants. In term infants, ALA supplementation was associated with increased weight and length at 12 mon, which was at least 4 mon after the end of dietary intervention. Developmental indices of term infants did not differ between groups. There was a transient improvement in the retinal function of preterm infants fed ALA-supplemented diets compared with controls. The findings suggest that ALA-supplemented diets improve the DHA status of infants. Further studies are needed to provide convincing evidence regarding the effects of ALA supplementation of formula on infant growth and development.

Maternal DHA and the development of attention in infancy and toddlerhood

Infants were followed longitudinally to document the relationship between docosahexaenoic acid (DHA) levels and the development of attention. Erythrocyte (red-blood cell; RBC) phospholipid DHA (percentage of total fatty acids) was measured from infants and mothers at delivery. Infants were assessed in infant-control habituation at 4, 6, and 8 months augmented with psychophysiological measures, and on free-play attention and distractibility paradigms at 12 and 18 months. Infants whose mothers had high DHA at birth showed an accelerated decline in looking over the 1st year and increases in examining during single-object exploration and less distractibility in the 2nd year. These findings are consistent with evidence suggesting a link between DHA and cognitive development in infancy.

The source of long-chain PUFA in formula supplements does not affect the fatty acid composition of plasma lipids in full-term infants

Supplementation of formulas for full-term infants with long-chain (LC) PUFA [arachidonic acid (AA) and docosahexaenoic acid (DHA)] at levels resembling human milk is recommended because they provide biochemical and functional benefits to the neonate. The objective of this work was to determine whether the source of dietary LC-PUFA affects the bioavailability in full-term infants. Treatment groups were as follows: full-term infants were fed from birth to 3 mo breast-milk (n = 11, 0.4 and 0.3 g/100 g total fatty acids as AA and DHA, respectively), formula containing LC-PUFA in the form of egg phospholipids (n = 12), or a formula supplemented with LC-PUFA in the form of triglycerides synthesized by single cells of algal and fungal microorganisms (n = 12). Both formulas provided 0.4 and 0.1 g/100 g total fatty acids as AA and DHA, respectively. We compared the fatty acid compositions of the main plasma lipid fractions (phospholipids, triglycerides, and cholesteryl esters) at birth and 3 mo. At 3 mo, lower levels of nervonic acid (NA), docosapentaenoic (DPA) acid, and DHA were found in all plasma lipid fractions from infants fed formula compared with those in the human milk-fed infants, irrespective of the source of the formula supplement (P < 0.02). These data demonstrate that the form of dietary LC-PUFA (triglycerides or phospholipids) does not influence their bioavailability. Similarly, absorption of LC-PUFA depends mainly on the lipid composition of the diet fed. These results suggest that the levels of NA, DPA, and DHA in formulas for full-term infants should be increased.

Fatty acid and sn-2 fatty acid composition in human milk from Granada (Spain) and in infant formulas

OBJECTIVE

To investigate differences in fatty acid and sn-2 fatty acid composition in colostrum, transitional and mature human milk, and in term infant formulas.

SETTING

Departament de Nutrició i Bromatologia, University of Barcelona, Spain and University Hospital of Granada, Spain.

SUBJECTS

One-hundred and twenty mothers and 11 available types of infant formulas for term infants.

DESIGN

We analysed the fatty acid composition of colostrum (n=40), transitional milk (n=40), mature milk (n=40) and 11 infant formulas. We also analysed the fatty acid composition at sn-2 position in colostrum (n=12), transitional milk (n=12), mature milk (n=12), and the 11 infant formulas.

RESULTS

Human milk in Spain had low saturated fatty acids, high monounsaturated fatty acids and high linolenic acid. Infant formulas and mature human milk had similar fatty acid composition. In mature milk, palmitic acid was preferentially esterified at the sn-2 position (86.25%), and oleic and linoleic acids were predominantly esterified at the sn-1,3 positions (12.22 and 22.27%, respectively, in the sn-2 position). In infant formulas, palmitic acid was preferentially esterified at the sn-1,3 positions and oleic and linoleic acids had higher percentages at the sn-2 position than they do in human milk.

CONCLUSION

Fatty acid composition of human milk in Spain seems to reflect the Mediterranean dietary habits of mothers. Infant formulas resemble the fatty acid profile of human milk, but the distribution of fatty acids at the sn-2 position is markedly different.

Maternal and infant essential fatty acid status in Havana, Cuba

BACKGROUND

Adequate intake of essential fatty acids (EFAs) is required for optimal development of the central nervous system and visual acuity in infants. Little information exists regarding the EFA status of vulnerable populations living in Southern regions.

OBJECTIVE

We examined the adequacy of EFA status in Cuban breast-feeding mothers and their infants.

DESIGN

Blood and breast-milk samples were obtained from a cross-sectional sample of mothers and term infants in Havana at 2 mo postpartum. We determined the fatty acid profiles of total lipids in breast milk, plasma, and erythrocytes and assessed infant visual acuity by using Teller acuity cards.

RESULTS

Of the 56 mothers and infants examined, none showed biochemical signs of poor EFA status. Compared with values reported in the literature, mothers had an adequate EFA profile in their breast milk, plasma, and erythrocytes. The docosahexaenoic acid (DHA) concentration in breast milk was 0.43 +/- 0.26% of total fatty acids. It appeared that these breast-fed infants had an adequate dietary supply of DHA, as reflected by the mean plasma and erythrocyte DHA concentrations (2.82 +/- 0.84% and 7.41 +/- 1.16% of total fatty acids, respectively). Infant visual acuity testing showed a mean of 2.00 +/- 0.68 cycles/degree, which is within the normal range of mean binocular acuities for 2-mo-old term infants. The data did not show any relation between EFA concentrations and visual acuity.

CONCLUSION

The results suggest that n-3 fatty acid deficiency and potential related deficits in early visual neural development are rare, if they exist at all, in breast-feeding women and their infants in Havana.

The emerging importance of dietary lipids, quantity and quality, in the global disease burden: the potential of aquatic resources

Achievement of Health-for-All, whereby people everywhere throughout their lives, have the opportunity to reach and maintain the highest attainable level of health is impossible whilst hunger, starvation, and malnutrition remain. Malnutrition covers a broad spectrum of ills, including undernutrition, specific nutrient deficiencies, and overnutrition; and it kills, maims, retards, cripples, blinds, and impairs human development on a truly massive scale worldwide. In the developing world in 1995, of the estimated 10.4 million deaths among children under 5 years of age, protein-energy malnutrition was an associated and causative factor in 5.1 million of these deaths (i.e. 49%). On the other hand, evidence has recently been compiled suggesting that of the more than 10 million cases of cancer that occurred in 1996, an estimated 30-40% (3-4 million every year) are preventable by feasible, appropriate diets, and by physical activity and maintenance of appropriate body weight. Malnutrition affects all age groups across the entire lifespan. From the moment of conception, throughout foetal life, iodine, folate and intrauterine nutrition have a profound influence on development, growth, morbidity, mortality, not only in utero and in early infancy, but on morbidity, physical and mental capacity throughout life. Despite significant improvements in world food supplies, health conditions, and availability of educational and social services, no population escapes malnutrition's grasp. All countries have significant population groups with some form of debilitating malnutrition. Malnutrition worldwide, includes a spectrum of nutrient-related disorders, deficiencies and conditions including the following major public health problems; Intrauterine growth retardation, protein-energy malnutrition, Iodine deficiency disorders, Vitamin A Deficiency, Iron Deficiency Anaemia and Overweight and Obesity (WHO, Website).

Soy-based formulae and infant growth and development: a review

Soy-based infant formulae, initially developed for infants who were lactose intolerant or allergic to cow's milk-based formulae, now account for >25% of the infant formulae sold in the United States. Formulations have changed over the years to improve digestibility, the stability and availability of minerals, and protein quality. Recent concerns have been raised regarding the phytoestrogenic isoflavone content of soy-based formulae. A systematic review of the literature was conducted to evaluate various measures of infant health and development in clinical studies comparing modern soy-based formulae with other diets and to document areas in which further research seems warranted. Results suggest that modern soy-based formulae support normal growth and nutritional status in healthy term infants in y 1 of life. However, there are very limited data on sexual and reproductive development or outcomes such as immune function, visual acuity/cognitive development and thyroid function. Available data do not provide evidence of meaningful differences in timing of maturation, sexual development or fertility in adolescents or adults. Nonetheless, given evidence suggesting that early exposure to soy and/or isoflavones might have long-term effects, further research following infants fed soy-based formulae into adulthood is warranted.

Lipids with an emphasis on long-chain polyunsaturated fatty acids

In addition to their role as a source of energy, several fatty acids are important components of cell membranes and/or precursors of biologically important eicosanoids. The long-chain polyunsaturated fatty acids, docosahexaenoic acid (DHA) and arachidonic acid (AA), are important for optimal visual function and neurodevelopment. These fatty acids are present in human milk but, until recently, have not been included in formulas marketed in the United States. Although the results of clinical trials assessing the effect of DHA and AA intakes on visual and cognitive development have been inconsistent, some studies suggest benefits. Adequate intake of these fatty acids may be especially important for the preterm infant.

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.

Recent advances in infant cognition: implications for long-chain polyunsaturated fatty acid supplementation studies

The assessment of cognitive function in early life has recently become an issue for consideration in long-chain polyunsaturated fatty acid (LC-PUFA) supplementation studies. This article reviews the various means by which such assessment has been done in past LC-PUFA supplementation studies and provides some background on recent advances in the measurement of infant cognition that may need to be considered when planning or designing future supplementation studies. These include (i) consideration of the specificity of LC-PUFA effects on cognition, (ii) inclusion of multiple tasks or levels of measurement as outcome measures, and (iii) a stronger emphasis on developmental processes in the design of such studies.

Polyunsaturated fatty acids and infant growth

Because of the rapid rate of growth during infancy, and the potentially deleterious effect of differences in the availability of dietary essential nutrients, growth is an important outcome variable in any study assessing a diet designed for infants. Nearly 10 yr after the first demonstration of reduced growth in preterm infants fed a fish oil-enriched formula, there is very little additional information to confirm or refute the finding that long-chain n-3 polyunsaturated fatty acid (LC-PUFA) intake can modulate growth in infants. To evaluate the issue of a possible relationship between PUFA intake and growth of infants, we reviewed a total of 32 randomized studies, 13 in preterm infants and 19 in term infants. From the data published to date, it seems clear that long-chain n-3 fatty acids can reduce growth achievement in preterm and term infants under some experimental conditions. However, the effect of n-3 PUFA supplementation on the growth of preterm and term infants appears to be minimal and of questionable clinical and/or physiologic relevance. Nonetheless, n-3 fatty acids have an effect on gene transcription, at least in some species, and this finding may provide important clues to the mechanism by which n-3 and n-6 fatty acids regulate growth.

Essential fatty acids in visual and brain development

Essential fatty acids are structural components of all tissues and are indispensable for cell membrane synthesis; the brain, retina and other neural tissues are particularly rich in long-chain polyunsaturated fatty acids (LC-PUFA). These fatty acids serve as specific precursors for eicosanoids, which regulate numerous cell and organ functions. Recent human studies support the essential nature of n-3 fatty acids in addition to the well-established role of n-6 essential fatty acids in humans, particularly in early life. The main findings are that light sensitivity of retinal rod photoreceptors is significantly reduced in newborns with n-3 fatty acid deficiency, and that docosahexaenoic acid (DHA) significantly enhances visual acuity maturation and cognitive functions. DHA is a conditionally essential nutrient for adequate neurodevelopment in humans. Comprehensive clinical studies have shown that dietary supplementation with marine oil or single-cell oil sources of LC-PUFA results in increased blood levels of DHA and arachidonic acid, as well as an associated improvement in visual function in formula-fed infants matching that of human breast-fed infants. The effect is mediated not only by the known effects on membrane biophysical properties, neurotransmitter content, and the corresponding electrophysiological correlates but also by a modulating gene expression of the developing retina and brain. Intracellular fatty acids or their metabolites regulate transcriptional activation of gene expression during adipocyte differentiation and retinal and nervous system development. Regulation of gene expression by LC-PUFA occurs at the transcriptional level and may be mediated by nuclear transcription factors activated by fatty acids. These nuclear receptors are part of the family of steroid hormone receptors. DHA also has significant effects on photoreceptor membranes and neurotransmitters involved in the signal transduction process; rhodopsin activation, rod and cone development, neuronal dendritic connectivity, and functional maturation of the central nervous system.

Growth and development in term infants fed long-chain polyunsaturated fatty acids: a double-masked, randomized, parallel, prospective, multivariate study

OBJECTIVE

To evaluate the effects of dietary intake of the long-chain polyunsaturated fatty acids, arachidonic acid (AA), and docosahexaenoic acid (DHA) on multiple indices of infant growth and development.

DESIGN

A double-masked, randomized, parallel trial was conducted with term infants fed formulas with or without AA+DHA for 1 year (N = 239). Reference groups of breastfed infants (N = 165) weaned to formulas with and without AA+DHA were also studied. Infants in the formula groups were randomized at </=9 days of age to a control formula with no AA or DHA (n = 77) or 1 of 2 otherwise identical formulas containing AA+DHA (AA, 0.46% and DHA, 0.14% of total fatty acids) from either egg-derived triglyceride (egg-DTG [n=80]) or fish oil and fungal oil (fish/fungal [n = 82]) at levels similar to the average in breast milk samples as measured in the reference group. All formulas contained 50% of energy from fat with the essential dietary fatty acids, linoleic acid (20% fatty acids) and alpha-linolenic acid (2% fatty acids). The main study outcomes were AA and DHA levels in plasma and red blood cells, and multiple measures of infant development at multiple ages from birth to 14 months: growth, visual acuity, information processing, general development, language, and temperament.

RESULTS

AA and DHA levels in plasma and red cells were higher in AA+DHA-supplemented groups than in the control formula group and comparable to those in reference groups. No developmental test results distinguished these groups. Expected differences in family demographics associated with breastfeeding were found, but no advantages to breastfeeding on any of the developmental outcome demonstrated.

CONCLUSIONS

These findings do not support adding AA+DHA to formulas containing 10% energy as linoleic acid and 1% energy as alpha-linolenic acid to enhance growth, visual acuity, information processing, general development, language, or temperament in healthy, term infants during the first 14 months after birth.infant development, breast feeding, infant formula, long-chain polyunsaturated fatty acids, docosahexaenoic acid.

Regulation of apolipoprotein secretion by long-chain polyunsaturated fatty acids in newborn swine enterocytes

Long-chain polyunsaturated fatty acids (LC-PUFA) are important in the development of the immature nervous system, and adding these fatty acids to infant formula has been proposed. To determine the effect of n-3 LC-PUFA on apolipoprotein secretion and lipid synthesis in newborn swine enterocytes, differentiated IPEC-1 cells were incubated for 24 h with docosahexaenoic acid (DHA; 22:6) or eicosapentaenoic acid (EPA; 20:5) complexed with albumin at a fatty acid concentration of 0.8 mM or albumin alone (control) added to the apical medium. Oleic acid (OA; 18:1) was used a control for lipid-labeling studies. Both DHA and EPA reduced apolipoprotein (apo) B secretion by one-half, whereas EPA increased apo A-I secretion. The increased apo A-I secretion occurred primarily in the high-density lipoprotein fraction. These changes in apoprotein secretion were not accompanied by significant changes in synthesis. Modest decreases in apo B mRNA levels were observed for DHA and EPA, whereas there were no changes in apo A-I mRNA abundance. EPA reduced cellular triacylglycerol labeling by one-half, and DHA and EPA decreased cellular phospholipid labeling compared with OA. Labeled triacylglycerol secretion was decreased 75% by EPA, and DHA doubled labeled phospholipid secretion. If present in vivo, these effects should be considered before supplementing infant formula with these fatty acids.

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.

Stereoacuity at age 3.5 y in children born full-term is associated with prenatal and postnatal dietary factors: a report from a population-based cohort study

BACKGROUND

Observational studies suggested that breast-feeding benefits the visual development of preterm children, which has been attributed to the presence of docosahexaenoic acid (DHA) in breast milk but not most formula milks. Randomized studies showed that preterm children require a dietary supply of DHA in the first few weeks of life for optimal visual development, but it is unclear whether full-term children experience similar benefits from breast milk or DHA supplements.

OBJECTIVE

The objective of this study was to compare stereoacuity at age 3.5 y in healthy, full-term children who were breast-fed and in similar children who had not been breast-fed after adjustment for socioeconomic status and maternal diet.

DESIGN

Prospectively collected data on maternal diet during pregnancy (including intake of oily fish), the child's diet, and the socioeconomic status of the family were examined. Stereoacuity at age 3.5 y was assessed.

RESULTS

Children who had been breast-fed for 4 mo were more likely to achieve high-grade stereopsis, or stereoscopic vision, than were children who had not been breast-fed (adjusted odds ratio: 2.77; 95% CI: 1.54, 4.97). The mother's antenatal blood DHA content was associated with her intake of oily fish (P < 0.0001). Children whose mothers ate oily fish during pregnancy were also more likely to achieve high-grade stereopsis than were children whose mothers did not eat oily fish (adjusted odds ratio: 1.57; 95% CI: 1.00, 2.45).

CONCLUSIONS

The results of this study suggest that for full-term infants, breast-feeding is associated with enhanced stereopsis at age 3.5 y, as is a maternal DHA-rich antenatal diet, irrespective of later infant feeding practice.

Diverse, region-specific effects of addition of arachidonic and docosahexanoic acids to formula with low or adequate linoleic and alpha-linolenic acids on piglet brain monoaminergic neurotransmitters

Differences in visual, auditory, and learning tasks have been reported for infants and animals given diets varying in omega-3 fatty acids, but the neurobiochemical basis for these changes is unclear. This study investigated the effect of feeding formula with 0.8% energy C18:2omega-6 + 0.05% C18:3omega-3 (low), or 8.3% C18:2omega-6 + 0.8% C18:3omega-3 (adequate), with and without 0.2% energy arachidonic acid (C20:4omega-6) and 0.16% docosahexanoic acid (C22:6omega-3), on monoaminergic neurotransmitters in different brain regions of piglets fed formula from birth to 18 d. The amount of C18:2omega-6 + C18:3omega-3 fed in formula had a significant effect on frontal cortex dopamine, 3,4-dihydroxyphenylacetic acid, homovanillic acid, serotonin, and 5-hydroxyindolacetic acid; striatum serotonin and inferior colliculus serotonin, resulting in lower concentrations in piglets fed the low compared with adequate C18:2omega-6 + C18:3omega-3 formula. Inclusion of arachidonic acid and docosahexanoic acid in the low, but not in the adequate, C18:2omega-6 + C18:3omega-3 formula resulted in increased concentrations of all monoamines in the frontal cortex, and in striatum and inferior colliculus serotonin. Feeding arachidonic acid and docosahexanoic acid in the formulas increased dopamine and 5-hydroxyindolacetic acid in superior and inferior colliculus, areas related to processing and integration of visual and auditory information. Higher dopamine and 5-hydroxyindolacetic acid were found in these regions even when arachidonic acid and docosahexanoic acid were added to the C18:2omega-6 + C18:3omega-3 adequate formula. This study suggests that functional changes among animals and infants fed diets varying in omega-6 and omega-3 fatty acids may involve altered neurotransmitter metabolism.

Effect of type of early infant feeding on fatty acid composition of plasma lipid classes in full-term infants during the second 6 months of life

BACKGROUND

Previously, the authors found significantly higher arachidonic and docosahexaenoic acid values in plasma lipids in 2-month-old full-term infants fed human milk than in those receiving formula. This is the report of data obtained in full-term infants during the second half of the first year of life.

METHODS

Healthy, full-term infants fed human milk (n = 12) or formula without preformed long-chain polyunsaturated fatty acids (n = 12) were investigated. Fatty acid composition of plasma lipid classes was determined by high-resolution capillary gas-liquid chromatography.

RESULTS

Linoleic acid acid values in plasma phospholipids (18.5 [3.94] vs. 20.79 [4.34]) and gamma-linolenic acid values in plasma cholesteryl esters (0.17 [0.09] vs. 0.27 [0.20]) and triacylglycerols (0.27 [0.18] vs. 0.46 [0.27]) were significantly (P < 0.05) lower in breast-fed infants than in those receiving formula. Data are percentage weight by weight shown as median (range from 1st to 3rd quartile) for breast-fed vs. formula fed infants, respectively. In contrast, arachidonic acid values in plasma phospholipids (10.05 [2.90] vs. 7.03 [1.87]; P < 0.01), cholesteryl esters (7.54 [3.58] vs. 4.09 [1.81]; P < 0.05), and triacylglycerols (1.28 [0.84] vs. 0.80 [0.39]; P < 0.05), as well as docosahexaenoic acid values in plasma phospholipids (1.92 [0.36] vs. 1.02 [0.31]; P < 0.001), cholesteryl esters (0.39 [0.13] vs. 0.15 [0.13]; P < 0.001), and triacylglycerols (0.17 [0.17] vs. 0.09 [0.04]; P < 0.01) were significantly higher in infants fed human milk than in those receiving formula.

CONCLUSION

Healthy, full-term infants fed formula without preformed dietary long-chain polyunsaturated fatty acids are unable to match the arachidonic and docosahexaenoic acid status of breast-fed infants even during the second half of the first year of life.

Dietary supplementation of arachidonic acid is associated with higher whole body weight and bone mineral density in growing pigs

Essential fatty acids are fundamental to normal growth and development, but North American formulas do not contain arachidonic (AA) and docosahexaenoic acid (DHA). The main objective of the present study was to determine whether addition of AA and DHA to formula elevates growth and bone mineralization in piglets. A secondary objective was to establish whether liver fatty acid composition is related to that of bone. Twelve 10-d-old male piglets were randomized to receive either a standard formula with an n-6:n-3 fatty acid ratio of 4.9:1.0 or the same formula made with an equal amount of fat but containing AA (0.5% wt/wt total fat) and DHA (0.1% wt/wt total fat) for 14 d. Piglets in the supplemented group had significantly (p < 0.05) higher weight and greater bone mineral density of the whole body, lumbar spine, and femur. No differences were observed in whole body length, calcium absorption, or biochemical markers of bone metabolism. Feeding AA resulted in lower linoleic acid (p < 0.05) and higher (p < 0.05) AA in liver total lipid (% wt/wt) and bone FFA (% wt/wt) but no change to DHA. Liver AA (% wt/wt total lipid) was positively related (p < 0.05) to growth, free AA (% wt/wt) in bone, bone mineral content, bone mineral density, and urinary prostaglandin E2 but negatively related (p < 0.05) to free linoleic acid in bone. Inverse relationships were observed when liver linoleic acid was substituted for liver AA as the independent variable. These data indicate that feeding AA is associated with elevated weight and higher whole body and regional bone mineral density.

Essential fatty acids in mothers and their neonates

Essential fatty acids (EFAs) and their long-chain polyenes (LCPs) are indispensable for human development and health. Because humans cannot synthesize EFAs and can only ineffectively synthesize LCPs, EFAs need to be consumed as part of the diet. Consequently, the polyunsaturated fatty acid (PUFA) status of the developing fetus depends on that of its mother, as confirmed by the positive relation between maternal PUFA consumption and neonatal PUFA status. Pregnancy is associated with a decrease in the biochemical PUFA status, and normalization after delivery is slow. This is particularly true for docosahexaenoic acid (DHA) because, on the basis of the current habitual diet, birth spacing appeared to be insufficient for the maternal DHA status to normalize completely. Because of the decrease in PUFA status during pregnancy, the neonatal PUFA status may not be optimal. This view is supported by the lower neonatal PUFA status after multiple than after single births. The neonatal PUFA status can be increased by maternal PUFA supplementation during pregnancy. For optimum results, the supplement should contain both n-6 and n-3 PUFAs. The PUFA status of preterm neonates is significantly lower than that of term infants, which is a physiologic condition. Because the neonatal DHA status correlates positively with birth weight, birth length, and head circumference, maternal DHA supplementation during pregnancy may improve the prognosis of preterm infants. In term neonates, maternal linoleic acid consumption correlates negatively with neonatal head circumference. This suggests that the ratio of n-3 to n-6 PUFAs in the maternal diet should be increased. Consumption of trans unsaturated fatty acids appeared to be associated with lower maternal and neonatal PUFA status. Therefore, it seems prudent to minimize the consumption of trans fatty acids during pregnancy.

Dietary essential fatty acids, long-chain polyunsaturated fatty acids, and visual resolution acuity in healthy fullterm infants: a systematic review

BACKGROUND

Biologically active neural tissue is rich in docosahexaenoic acid (DHA), an omega-3 long-chain polyunsaturated fatty acid (LCPUFA). We conducted a systematic review to examine the nature of discordant results from studies designed to test the hypothesis that dietary DHA leads to better performance on visually-based tasks in healthy, fullterm infants. We also conducted a meta-analysis to derive combined estimates of behavioral- and electrophysiologic-based visual resolution acuity differences and sample sizes that would be useful in planning future research.

STUDY DESIGN AND METHODS

Twelve empirical studies on LCPUFA intake during infancy and visual resolution acuity were identified through bibliographic searches, examination of monograph and review article reference lists, and written requests to researchers in the field. Works were reviewed for quality and completeness of information. Study design and conduct information was extracted with a standardized protocol. Acuity differences between groups consuming a source of DHA and groups consuming DHA-free diets were calculated as a common outcome from individual studies; this difference score was evaluated against a null value of zero and then used, with the method of DerSimonian and Laird (Meta-analysis in clinical trials. Control Clin Trials 1986;7:177-188), to derive combined estimates of visual resolution acuity differences within seven age categories. RESULTS OF RANDOMIZED COMPARISONS: The combined visual resolution acuity difference measured with behaviorally based methods between DHA-supplemented formula fed groups and DHA-free formula fed groups is 0.32+/-0.09 octaves (combined difference+/-S.E.M., P=0.0003) at 2 months of age. The direction of this value indicates higher acuity in DHA-fed groups. RESULTS OF NON-RANDOMIZED STUDY DESIGNS: The combined visual resolution acuity difference measured with behaviorally based methods between human milk fed groups and DHA-free formula fed groups is 0.49+/-0.09 octaves (P< or =0.000001) at 2 months of age and 0.18+/-0.08 octaves (P=0.04) at 4 months of age. Acuity differences for electrophysiologic-based measures are also greater than zero at 4 months (0.37+/-0.16 octaves, P=0.02).

CONCLUSION

Some aspect of dietary n-3 intake is associated with performance on visual resolution acuity tasks at 2, and possibly, 4 months of age in healthy fullterm infants. Whether n-3 intake confers lasting advantage in the development of visually based processes is still in question.

Essential fatty acid metabolism in the micropremie

Lipids are structural components of all tissues and are indispensable for cell membrane synthesis. The brain, retina, and other neural tissues are particularly rich in LCPUFAs, affecting neural structural development and function. LCPUFAs serve also as specific precursors for eicosanoid production (prostaglandins, prostacyclins, thromboxanes, and leukotrienes). These autocrine and paracrine mediators are powerful regulators of numerous cell and tissue functions (e.g., thrombocyte aggregation, inflammatory reactions, and leukocyte functions, vasoconstriction and vasodilatation, blood pressure, bronchial constriction, uterine contraction). Dietary lipid intake affects cholesterol metabolism at an early age and is associated with cardiovascular morbidity and mortality in later life. Over recent years, the role of fatty acids in modulating signal transduction and regulating gene expression have been described, emphasizing the complex of fatty acid effects. Dietary fatty acids, especially LCPUFA, can have significant effects in the modulation of developmental processes affecting the clinical outcomes of extremely premature infants.

Comparison of the fatty acid composition of total lipids and phospholipids in breast milk from Japanese women

Fatty acid (FA) composition of total lipids (TL) and phospholipids (PL) in breast milk obtained from 20 normal delivery healthy women in Tokyo, Japan was analyzed. Total lipids were extracted from the samples and then PL, consisting of phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), sphingomyelin (Sph) and phosphatidylinositol (PI), were separated by two-dimensional thin-layer chromatography. The FA composition of TL and PL was analyzed by gas liquid-chromatography. Compared with previous reports, the contents of eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) in TL from Japanese women were higher than those from Chinese and Canadian women, which may be caused by different dietary habits and food types consumed by those populations. The contents of arachidonic acid (AA; 20:4n-6), EPA and DHA in PE and PI were much higher than those in PC. In addition, no significant correlation of EPA or DHA content was found between TL and PL. The findings indicate that PL especially PE and PI in human milk may be a source of EPA and DHA for infants in the rapid developmental stage. These results should be considered in infant formula production.

Essential fatty acids in infant nutrition: lessons and limitations from animal studies in relation to studies on infant fatty acid requirements

Animal studies have been of pivotal importance in advancing knowledge of the metabolism and roles of n-6 and n-3 fatty acids and the effects of specific dietary intakes on membrane composition and related functions. Advantages of animal studies include the rigid control of fatty acid and other nutrient intakes and the degree, timing, and duration of deficiency or excess, the absence of confounding environmental and clinical variables, and the tissue analysis and testing procedures that cannot be performed in human studies. However, differences among species in nutrient requirements and metabolism and the severity and duration of the dietary treatment must be considered before extrapolating results to humans. Studies in rodents and nonhuman primates fed diets severely deficient in alpha-linolenic acid (18:3n-3) showed altered visual function and behavioral problems, and played a fundamental role by identifying neural systems that may be sensitive to dietary n-3 fatty acid intakes; this information has assisted researchers in planning clinical studies. However, whereas animal studies have focused mainly on 18:3n-3 deficiency, there is considerable clinical interest in docosahexaenoic acid (22:6n-3) and arachidonic acid (20:4n-6) supplementation. Information from animal studies suggests that brain and retinal concentrations of 22:6n-3 plateau with 18:3n-3 intakes of approximately 0.7% of energy, but this requirement is influenced by dietary 18:2n-6 intake. Blood and tissue concentrations of 22:6n-3 increase as 22:6n-3 intake increases, with adverse effects on growth and function at high intakes. Animal studies can provide important information on the mechanisms of both beneficial and adverse effects and the pathways of brain 22:6n-3 uptake.

Infant vision and retinal function in studies of dietary long-chain polyunsaturated fatty acids: methods, results, and implications

Animal and human studies have documented several effects of different dietary and tissue concentrations of long-chain polyunsaturated fatty acids (LCPUFAs) on retinal function and vision. The enhanced visual development associated with increased intakes of LCPUFAs, particularly docosahexaenoic acid (DHA), provides the strongest evidence for the importance of these fatty acids in infant nutrition. The 2 primary visual measures used to assess the efficacy of infant formula LCPUFA supplementation are the electroretinogram and visual acuity. This review briefly describes the methodology, neural basis, and interpretation of these measures, as well as other measures of visual development that may be used to extend the functional evaluation of infants fed formulas with different fatty acid compositions.

n-3 polyunsaturated fatty acid requirements of term infants

The benchmarks for human nutrient requirements are the recommended dietary intakes (RDIs). However, the RDIs are set to prevent a clinical deficiency state in an otherwise healthy population and there are few nutrient recommendations set with the goal of achieving an optimal or maximal state of nutrition and health. This is becoming an increasing challenge with the introduction of many nutraceuticals and functional foods, a prime example being the debate surrounding the introduction of long-chain polyunsaturated fatty acids (LCPUFAs) into infant formulas. Most expert nutrition committees have used the fatty acid composition of breast milk as a basis for recommendations for infant formulas, with little information on the minimum absolute requirement for essential PUFAs. It has been difficult to determine a minimum requirement for fatty acids because 1) LCPUFAs can be synthesized from precursor fatty acids, 2) plasma n-3 LCPUFA concentrations representing deficiency and sufficiency are not clearly defined, and 3) there are no recognized clinical tests for n-3 LCPUFA deficiency and sufficiency. Therefore, there is a clear need to associate a measure of LCPUFA status with a specific functional outcome before any recommendations can be made for achieving optimal or maximal LCPUFA status.

Lipids in human milk

I have reviewed recent (March 1995-December 1997) papers on human milk lipids including many on fatty acid (FA) composition. The effects of maternal diets on the profiles are apparent. However, more data on the composition of milk lipids are needed. It is noteworthy that so few papers on milk FA composition have reported analyses using high-resolution gas-liquid chromatography columns. Two of these were on milk from women in North America. The diets in North America are varied and the number of analyses few. We do not have a reliable data base showing the ranges of biologically important acids. Except for the gangliosides, few new data on the other lipids appeared during this period.