Importance of polyunsaturated fatty acids of the n-6 and n-3 families for early human development

Maternal long chain polyunsaturated fatty acid status and pregnancy complications

Maternal nutrition plays a crucial role in influencing fetal growth and birth outcome. Any nutritional insult starting several weeks before pregnancy and during critical periods of gestation is known to influence fetal development and increase the risk for diseases during later life. Literature suggests that chronic adult diseases may have their origin during early life - a concept referred to as Developmental Origins of Health and Disease (DOHaD) which states that adverse exposures early in life "program" risks for later chronic disorders. Long chain polyunsaturated fatty acids (LCPUFA), mainly omega-6 and omega-3 fatty acids are known to have an effect on fetal programming. The placental supply of optimal levels of LCPUFA to the fetus during early life is extremely important for the normal growth and development of both placenta and fetus. Any alteration in placental development will result in adverse pregnancy outcome such as gestational diabetes mellitus (GDM), preeclampsia, and intrauterine growth restriction (IUGR). A disturbed materno-fetal LCPUFA supply is known to be linked with each of these pathologies. Further, a disturbed LCPUFA metabolism is reported to be associated with a number of metabolic disorders. It is likely that LCPUFA supplementation during early pregnancy may be beneficial in improving the health of the mother, improving birth outcome and thereby reducing the risk of diseases in later life.

Maternal docosahexaenoic acid intake levels during pregnancy and infant performance on a novel object search task at 22 months

This study investigated maternal prenatal docosahexaenoic acid (DHA) intake and infant cognitive development at 22 months. Estimates for second- and third-trimester maternal DHA intake levels were obtained using a comprehensive Food Frequency Questionnaire. Infants (n = 67) were assessed at 22 months on a novel object search task. Mothers' DHA intake levels were divided into high or low groups, with analyses revealing a significant positive effect of third-trimester DHA on object search task performance. The third trimester appears to be a critical time for ensuring adequate maternal DHA levels to facilitate optimum cognitive development in late infancy.

Exposure to DEHP decreased four fatty acid levels in plasma of prepartum mice

Maternal exposure to di(2-ethylhexyl) phthalate (DEHP) decreased the plasma triglyceride in prepartum mice. To identify the fatty acid (FA) species involved and to understand the underlying mechanisms, pregnant Sv/129 wild-type (mPPARα), peroxisome proliferator-activated receptor α-null (Pparα-null) and humanized PPARα (hPPARα) mice were treated with diets containing 0%, 0.01%, 0.05% or 0.1% DEHP. Dams were dissected on gestational day 18 together with fetuses, and on postnatal day 2 together with newborns. n-3/n-6 polyunsaturated, saturated, and monounsaturated FAs in maternal plasma and in liver of wild-type offspring, and representative enzymes for FA desaturation and elongation in maternal liver, were measured. The plasma levels of linoleic acid, α-linolenic acid, palmitic acid and oleic acid were higher in the pregnant control mPPARa mice than in Ppara-null and hPPARa mice. DEHP exposure significantly decreased the levels of these four FAs only in pregnant mPPARα mice. Plasma levels of many FAs were higher in pregnant mice than in postpartum ones in a genotype-independent manner, while it was lower in the livers of fetuses than pups. DEHP exposure slightly increased hepatic arachidonic acid, α-linolenic acid, palmitoleic acid and oleic acid in fetuses, but not in pups. However, DEHP exposure did not clearly influence FA desaturase 1 and 2 nor elongase 2 and 5 expressions in the liver of all maternal mice. Taken together, the levels of plasma four FAs with shorter carbon chains were higher in pregnant mPPARα mice than in other genotypes, and DEHP exposure decreased these specific FA concentrations only in mPPARα mice, similarly to triglyceride levels.

Associations between term birth dimensions and prenatal exposure to essential and trans fatty acids

BACKGROUND

Certain essential long-chain polyunsaturated fatty acids (LCPUFAs) are considered important for fetal growth and brain development, whereas industrial trans fatty acids (mainly 18:1trans) have been associated with negative effects. The aim of this study was to investigate associations between term birth dimensions and prenatal exposure to some of these fatty acids, reflected by neonatal fatty acid concentrations at birth.

METHODS

Data of up to 700 infant-mother pairs from the Maastricht Essential Fatty Acid Birth Cohort were used for the present study. Unadjusted and multivariable-adjusted linear regression analyses were performed to investigate associations between birth weight, birth length or head circumference and relative concentrations of docosahexaenoic acid (DHA), arachidonic acid (AA), dihomo-gamma-linolenic acid (DGLA) and trans-octadecenoic acids (18:1t) measured in phospholipids of the walls of umbilical arteries and veins, and in umbilical cord plasma and erythrocytes.

RESULTS

After optimal adjustment, a significant negative association was observed between birth weight and umbilical plasma DHA concentrations. Negative associations were also found for AA concentrations measured in umbilical plasma and in arterial and venous vessel walls. Birth length was negatively related to arterial vessel wall AA concentrations only. A significant negative association was observed for the relationship between 18:1t in cord erythrocytes and birth weight. For DGLA no significant associations were observed.

CONCLUSIONS

Results seem to preclude a role of DHA and AA as growth factors per se. Their negative relationships with birth dimensions may result from a limited maternal-fetal LCPUFA transfer capacity. Potential effects of 18:1t and DGLA on birth dimensions are probably small or non-existing.

Associations between neonatal birth dimensions and maternal essential and trans fatty acid contents during pregnancy and at delivery

Since birth dimensions have prognostic potential for later development and health, possible associations between neonatal birth dimensions and selected maternal plasma fatty acid contents were investigated, using data from 782 mother–infant pairs of the Maastricht Essential Fatty Acid Birth cohort. Unadjusted and multivariable-adjusted regression analyses were applied to study the associations between birth weight, birth length or head circumference and the relative contents of DHA, arachidonic acid (AA), dihomo-γ-linolenic acid (DGLA) and 18 : 1trans (18 : 1t) in maternal plasma phospholipids sampled during early, middle and late pregnancies, and at delivery. Where appropriate, corrections were made for relevant covariables. Significant ‘positive’ associations were observed between maternal DHA contents (especially early in pregnancy) and birth weight (B = 52·10 g, 95 % CI 20·40, 83·80) and head circumference (B = 0·223 cm, 95 % CI 0·074, 0·372). AA contents at late pregnancy were ‘negatively’ associated with birth weight (B = − 44·25 g, 95 % CI − 68·33, − 20·16) and birth length (B = − 0·200 cm, 95 % CI − 0·335, − 0·065). Significant ‘negative’ associations were also observed for AA contents at delivery and birth weight (B = − 27·08 g, 95 % CI − 47·11, − 7·056) and birth length (B = − 0·207 cm, 95 % CI − 0·330, − 0·084). Maternal DGLA contents at delivery were also significantly ‘negatively’ associated with neonatal birth weight (B = − 85·76 g, 95 % CI − 130·9, − 40·61) and birth length (B = − 0·413 cm, 95 % CI − 0·680, − 0·146). No significant associations were observed for maternal 18 : 1t contents. We conclude that during early pregnancy, maternal DHA content may programme fetal growth in a positive way. Maternal AA and DGLA in late pregnancy might be involved in fetal growth limitation.

Effects of n-3 long chain polyunsaturated fatty acid supplementation on visual and cognitive development throughout childhood: a review of human studies

The present paper evaluates the most recent randomized controlled trials assessing the efficacy of n-3 LCPUFA supplementation (with or without n-6 LCPUFA) during pregnancy, lactation, infancy and childhood on visual and cognitive development. Available evidence suggests a beneficial effect of maternal n-3 LCPUFA supplementation during pregnancy and lactation on cognitive development of infants and children, but not for visual development. Evidence for an effect of LCPUFA supplementation of preterm and term infants on cognitive development of infants remains inconclusive. However, supplementing term infants with daily doses of 100 mg docosahexaenoic acid plus 200 mg arachidonic acid improves visual development as measured by electrophysiological tests. Evidence for benefits of n-3 LCPUFA on cognitive development in healthy children older than 2 years of age is too limited to allow a clear conclusion. Taken together, the evidence for potential benefits of LCPUFA supplementation is promising but yet inconclusive.

Year-round high arachidonic acid levels in herbivorous rabbit fish Siganus fuscescens tissues

To identify a stable resource of 20:4 n-6 (arachidonic acid, AA) in marine fish tissues, the lipid profiles of Siganus fuscescens organs (muscle, liver, and other viscera) and stomach contents were examined throughout the year. Crude total lipid (TL) contents in respective organs showed seasonal variations and were high in winter and low in summer. The main FA in TL were 16:0, 18:0, 16:1n-7, 18:1n-9, AA, and 22:6n-3 (DHA). These FA were those generally observed in marine fish lipids, except for comparatively high levels of AA. In TL of muscle and liver, AA showed relatively high values during the period from late May to August (muscle, 4.6-13.1%; liver, 4.5-9.1%), compared with other seasons (muscle, 4.3-9.5%; liver, 3.6-8.4%). The AA levels in TL of other viscera and stomach contents fluctuated (other viscera, 2.0-10.7%; stomach contents, 7.6-26.7%). Regardless of the fishing season, each organ contained a higher level of AA in polar lipids (PL) than in neutral lipids. It was concluded that the fish contain comparatively high levels of AA in their TL throughout the year, and they accumulate AA characteristically in their tissue PL, probably from dietary food sources. Moreover, it was suggested that S. fuscescens has potential utility as a natural marine source of nutritional lipids, because the fish contain comparatively high levels of DHA and AA.

Alpha-linolenic acid supplementation during human pregnancy does not effect cognitive functioning

Increasing evidence suggests a positive association between docosahexaenoic acid (DHA, 22:6n-3) and cognitive performance. In addition, pregnancy is associated with a reduction of the DHA status and cognitive deficits. In the current study, cognition was assessed in pregnant women receiving a margarine enriched with alpha-linolenic acid (ALA, 18:3n-3, the ultimate dietary precursor of DHA) and some linoleic acid (LA, 18:2n-6, to prevent a possible reduction in n-6 fatty acids). A control group received a margarine enriched with LA only. ALA supplementation hardly affected the maternal DHA status and no significant differences were found in cognitive performance between the two groups. This indicates that ALA supplementation during pregnancy does not affect cognitive performance during and 32 weeks after gestation. At week 14 of pregnancy and 32 weeks after delivery, higher plasma DHA levels were associated with lower cognitive performance as indicated by longer reaction times on the finger precuing task (partial correlation coefficients 0.3705 and 0.4633, respectively, P<0.01). Since this could imply an unexpected adverse association between DHA and certain aspects of cognitive functioning this certainly needs further investigation.