Comparison of bloodstream fatty acid composition from African-American women at gestation, delivery, and postpartum

Sex differences in hippocampal-dependent memory and the hippocampal lipidome in adolescent rats raised on diets with or without DHA

Recent studies suggest the effects of DHA supplementation on human memory may differ between females and males during infancy, adolescence, and early adulthood, but the underlying mechanisms are not clear. As a result, this study sought to examine the spatial memory and brain lipidomic profiles in female and male adolescent rats with or without a DHA-enriched diet that began perinatally with the supplementation of dams. Spatial learning and memory were examined in adolescent rats using the Morris Water Maze beginning at 6 weeks of age and animals were sacrificed at 7 weeks of age to permit isolation of brain tissue and blood samples. Behavioral testing showed that there was a significant diet x sex interaction for two key measures of spatial memory (distance to zone and time spent in the correct quadrant during the probe test), with female rats benefiting the most from DHA supplementation. Lipidomic analyses suggest levels of arachidonic acid (ARA) and n-6 docosapentaenoic acid (DPA) containing phospholipid species were lower in the hippocampus of DHA supplemented compared with control animals, and principal component analyses revealed a potential dietary treatment effect for hippocampal PUFA. Females fed DHA had slightly more PE P-18:0_22:6 and maintained levels of PE 18:0_20:4 in the hippocampus in contrast with males fed DHA. Understanding how DHA supplementation during the perinatal and adolescent periods changes cognitive function in a sex-specific manner has important implications for determining the dietary requirements of DHA. This study adds to previous work highlighting the importance of DHA for spatial memory and provides evidence that further research needs to consider how DHA supplementation can cause sex-specific changes.

Supplementation With Fish Oil in Pregnancy Reduces Gastroenteritis in Early Childhood

BACKGROUND

We hypothesized that insufficient intake of fish oil-derived omega-3 long-chain polyunsaturated fatty acids (n-3 LCPUFAs) during pregnancy is a contributing factor to gastroenteritis in early childhood. We examined the effect of n-3 LCPUFA supplementation on gastroenteritis symptoms in the offspring's first 3 years of life.

METHODS

This was a double-blinded, randomized controlled trial whereby 736 mothers were administered n-3 LCPUFA or control from pregnancy week 24 until 1 week after birth. We measured the number of days with gastroenteritis, number of episodes with gastroenteritis, and the risk of having a gastroenteritis episode in the first 3 years of life.

RESULTS

A median reduction of 2.5 days with gastroenteritis (P = .018) was shown, corresponding to a 14% reduction in the n-3 LCPUFA group compared with controls in the first 3 years of life (P = .037). A reduction in the number of gastroenteritis episodes (P = .027) and a reduced risk of having an episode (hazard ratio, 0.80 [95% confidence interval, .66-.97]; P = .023) were also shown.

CONCLUSIONS

Fish oil supplementation from the 24th week of pregnancy led to a reduction in the number of days and episodes with gastroenteritis symptoms in the first 3 years of life. The findings suggest n-3 LCPUFA supplementation as a preventive measure against gastrointestinal infections in early childhood.

CLINICAL TRIALS REGISTRATION

NCT00798226.

Association of Fatty Acid Desaturase 1 rs174547 Polymorphism with the Composition of Long-Chain Polyunsaturated Fatty Acids in Serum Glycerophospholipids during Pregnancy

The increase in fetal requirements of long-chain polyunsaturated fatty acids (LCPUFAs) during pregnancy alters maternal fatty acid metabolism, and therefore, fatty acid desaturase (FADS) gene polymorphisms may change blood fatty acid composition or concentration differently during pregnancy. We investigated the relationship between a FADS1 single-nucleotide polymorphism (SNP) and maternal serum LCPUFA levels in Japanese pregnant women during the first and third trimesters and at delivery. Two hundred and fifty-three pregnant women were included, and fatty acid compositions of glycerophospholipids in serum (weight %) and the FADS1 SNP rs174547 (T/C) were analyzed. LCPUFAs, including arachidonic acid (ARA) and docosahexaenoic acid (DHA), significantly decreased from the first to the third trimester of pregnancy. Furthermore, DHA significantly decreased from the third trimester of pregnancy to delivery. At all gestational stages, linoleic acid (LA) and α-linolenic acid were significantly higher with the number of minor FADS1 SNP alleles, whereas γ-linolenic acid and ARA and the ARA/LA ratio were significantly lower. DHA was significantly lower with the number of minor FADS1 SNP alleles only in the third trimester and at delivery, suggesting that genotype effects become more obvious as pregnancy progresses.

Dietary Intake of n-6:n-3 Polyunsaturated Fatty Acids among Pregnant Chinese Women in Different Trimesters

This study aimed to investigate the dietary n-6:n-3 PUFA (polyunsaturated fatty acids) intake of pregnant Chinese women in different trimesters. We conducted a cross-sectional study for 300 singleton pregnant women in Hefei city, China. The dietary intake of pregnant women were measured by a 3-d food record. Energy and nutrient intake for the 3 d were calculated according to the Chinese food composition table (Standard Version). The ANOVA and Kruskal-Wallis test were performed to analyze the dietary fatty acids intake of pregnant women. In the first, second and third trimester, the intake of n-6:n-3 PUFA were 5.87±2.37, 6.03±2.89, 6.14±2.26, respectively, without significant difference (p>0.05). But it was all slightly higher than the recommendation for general population (4-6) of Chinese Nutrition Society. An adequate and balanced intake of n-6 and n-3 fatty acids, from a well-balanced diet, should be recommended for pregnant women.

African American Women with Cardiometabolic Complications of Pregnancy Have Decreased Serum Abundance of Specialized Pro-Resolving Lipid Mediators and Endocannabinoids

African American (AA) women experience higher rates of maternal morbidity and mortality compared to US women of other racial/ ethnic groups. Cardiometabolic complications of pregnancy (including gestational diabetes, gestational hypertension, and preeclampsia) are leading contributors to maternal morbidity and mortality. Marked changes in circulating lipids are known to accompany cardiometabolic complications of pregnancy. Serum concentrations of docosahexaenoic acid (DHA) have been shown to be inversely correlated with risk for preeclampsia. DHA is a biosynthetic precursor of a class of specialized pro-resolving mediators (SPMs), resolvins, that have anti-inflammatory properties and are also associated with hypertensive disorders of pregnancy. We employed targeted lipidomics to characterize the distribution of DHA-containing phospholipids and SPMs in maternal serum collected in early and late pregnancy (8-14 weeks and 24-30 weeks gestation, respectively) to identify key lipids that are dysregulated during pregnancy in AA women who develop cardiometabolic complications. We identified a lipid signature in early pregnancy serum samples of AA women that is predictive of cardiometabolic complications of pregnancy with 74% accuracy. These are Resolvin D1, Resolvin E1, 2-AG, PGE2-glyerol ester, and 36:6 PC. These findings suggest that there are blood-based markers detectable in early pregnancy that can potentially identify persons at risk and tailor clinical interventions.

Geographic variations and determinants of EPA plus DHA and EPA alone in pregnant and lactating women from China

EPA and DHA are essential for maternal and fetal health, but epidemiological data are sparse in China. We examined the trends of EPA alone and a combination of EPA plus DHA in pregnant and lactating women in three distinct geographic regions in China and explored their potential influencing factors. A total of 1015 healthy women during mid-pregnancy, late pregnancy or lactation were recruited from Weihai (coastland), Yueyang (lakeland) and Baotou (inland) cities of China between May and July of 2014. Maternal EPA and DHA concentrations (percentage of total fatty acids) in plasma and erythrocytes were measured by capillary GC. Adjusted EPA plus DHA concentrations in both plasma and erythrocytes significantly declined from mid-pregnancy (2·92 %, 6·95 %) to late pregnancy (2·20 %, 6·42 %) and lactation (2·40 %, 6·29 %) (P_trend < 0·001); and both concentrations were highest in coastland, followed by lakeland, and lowest in inland (P < 0·001). Regarding EPA alone, the concentrations were higher in women during lactation or late pregnancy and in women in coastland and inland areas. Moreover, concentrations of EPA or EPA plus DHA were higher in women with older age, higher education, higher annual family income per capita and higher dietary intake of marine aquatic product and mutton. In lactating women, erythrocyte EPA concentration was higher in those having breast-feeding partially v. exclusively. In conclusion, maternal plasma and erythrocyte concentrations of EPA plus DHA or EPA alone differed with geographic regions, physiological periods and maternal characteristics, indicating a need of population-specific health strategies to improve fatty acids status in pregnant and lactating women.

Human milk fatty acid composition and its association with maternal blood and adipose tissue fatty acid content in a cohort of women from Europe

Purpose

Human milk (HM) composition is influenced by factors, like maternal diet and body stores, among other factors. For evaluating the influence of maternal fatty acid (FA) status on milk FA composition, the correlation between FA content in HM and in maternal plasma, erythrocytes, and adipose tissue was investigated.

Methods

223 European women who delivered at term, provided HM samples over first four months of lactation. Venous blood and adipose tissue (only from mothers who consented and underwent a C-section delivery) were sampled at delivery. FAs were assessed in plasma, erythrocytes, adipose tissue, and HM. Evolution of HM FAs over lactation and correlations between FA content in milk and tissues and between mother’s blood and cord blood were established.

Results

During lactation, arachidonic acid (ARA) and docosahexaenoic acid (DHA) significantly decreased, while linoleic acid (LA), alpha-linolenic acid (ALA), and eicosapentaenoic acid (EPA) remained stable. Positive correlations were observed between HM and adipose tissue for palmitic, stearic, oleic, and polyunsaturated fatty acids (PUFAs). Correlations were found between milk and plasma for oleic, LA, ARA, ALA, DHA, monounsaturated fatty acids (MUFAs), and PUFAs. No correlation was observed between erythrocytes and HM FAs. LA and ALA were more concentrated in maternal blood than in infant blood, contrary to ARA and DHA, supporting that biomagnification of LCPUFAs may have occurred during pregnancy.

Conclusions

These data show that maternal adipose tissue rather than erythrocytes may serve as reservoir of PUFAs and LCPUFAs for human milk. Plasma also supplies PUFAs and LCPUFAs to maternal milk. If both, adipose tissue and plasma PUFAs, are reflection of dietary intake, it is necessary to provide PUFAs and LCPUFAs during pregnancy or even before conception and lactation to ensure availability for mothers and enough supply for the infant via HM.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-021-02788-6.

Blood fatty acid analysis reveals similar n-3 fatty acid composition in non-pregnant and pregnant women and their neonates in an Israeli pilot study

Maternal docosahexaenoic acid (DHA) is required during pregnancy to supply for normal fetal growth and development. This pilot study aimed to assess the unknown fatty acid (FA) composition in a cohort of non-pregnant and pregnant Israeli women at term and their offspring on a normal diet without n-3 FA supplementation. The fatty acid profile, analyzed using gas chromatography, showed significantly higher plasma monounsaturated (MUFA) and lower n-6 FA percent distribution with similar n-3 index, in pregnant compared to non-pregnant women. RBC exhibited significantly higher MUFA with similar n-3 index, in pregnant compared to non-pregnant women. N-3 FA significantly correlated between neonates' plasma, with higher n-3 index, and pregnant women's DHA. Conclusion: DHA levels in non-pregnant and pregnant Israeli women at term were comparable and the DHA in pregnant women's plasma positively correlated with their neonate's level, suggesting an efficient mother-fetus FA transfer and/or fetal fatty acid metabolism to longer FA products.

Evidence of multiple hepatic mechanisms to mobilize docosahexaenoic acid into dam plasma during pregnancy in chow-fed sprague dawley rats

Fetal brain growth requires considerable amounts of docosahexaenoic acid (DHA) during late pregnancy that is associated with increased maternal/dam plasma levels of PC 16:0_22:6 (palmitoyl docosahexaenoyl phosphatidylcholine). While biosynthesis of DHA during pregnancy is upregulated, the mechanisms responsible for the incorporation of dam DHA into PC 16:0_22:6 are not understood. The present study used a discovery approach combining untargeted lipidomics of plasma and liver (n = 3/group) with semi-targeted qPCR of hepatic gene products (n = 6/group) to identify metabolic pathways related to DHA metabolism, with a hypothesis that an upregulated acyltransferase involved in PC remodeling would be identified. Sprague Dawley rats were fed a commercial rodent chow throughout the study and samples were collected before pregnancy (baseline), at 15 and 20 days of pregnancy, and 7 days postpartum. Plasma and hepatic PC 16:0_22:6 was significantly increased (by 79% and 194%, respectively) at day 20 of pregnancy. An increase in hepatic DG (diacylglycerol) 16:0_22:6 (by 243%) and significant decreases in Pla2G15 (0.4-fold) and Pla2G16 (0.6-fold) at day 20 of pregnancy, no changes in Lpcat1-4, and an abundant pool of hepatic pool PE (phosphatidylethanolamine) 16:0_22:6 suggest that plasma PC 16:0_22:6 is not being produced by fatty acyl remodeling during pregnancy. The increase in plasma PC 16:0_22:6 during pregnancy appears to be due to an increase in de novo synthesis of PC and both the CDP-choline and phosphatidylcholine methyltransferase pathways are implicated. There was also evidence suggesting channeling of DHA into PC and lipoprotein assembly may be occurring. Targeted research is necessary to confirm these findings, but the results of this study indicate metabolic adaptions to enable maternal/dam resiliency towards meeting the fetal/pup demand for DHA during pregnancy.

Establishing age-stratified red blood cell fatty acid reference ranges using model-based clustering and iterative application of the harris-boyd method

BACKGROUND

The current assessment of nutritional status and diagnosis of essential fatty acids deficiency (EFAD) utilizes the analysis of long-chain fatty acids (LCFAs) in serum or plasma; however, these concentrations do not represent habitual LCFA intake. LCFAs in red blood cells (RBCs) are less prone to intra-individual variability and exclude the need for fasting, which is unrealistic in pediatric populations. Our study objective was to characterize the RBC LCFA profiles in pediatric and adult reference populations and establish age-specific reference intervals (RIs).

METHODS

Twenty-one LCFAs in RBCs were measured in 523 pediatric and adult controls by gas chromatography-mass spectrometry. Model-based clustering was used to identify possible age subgroups. After removing outliers by the Tukey method, initial age subgroups were then compared using the Harris-Boyd method in an iterative manner. RIs (95%), with confidence intervals (90%), in the final age groups were established using parametric or non-parametric statistics.

RESULTS

Our data showed heterogeneous changes in the concentrations of most LCFAs and the EFAD biomarkers (mead acid, Triene/Tetraene ratio) during infancy. Model-based clustering identified six initial age subgroups per fatty acid, on average. Our application of the iterative Harris-Boyd method decreased the average number of age groups to three per fatty acid, with 13 total unique age cut-offs. Finally, using these age groups, we established age-specific RIs for 21 fatty acids, six group totals, and the Triene/Tetraene ratio.

CONCLUSION

Our study revealed significant age-dependent changes in RBC fatty acid profiles warranting separate pediatric and adults RIs. Model-based clustering and the iterative application of the Harris-Boyd method were successfully used to establish RBC fatty acid RIs for an objective assessment of long-term nutritional status in pediatric and adult populations.

Baseline red blood cell and breast milk DHA levels affect responses to standard dose of DHA in lactating women on a controlled feeding diet

BACKGROUND

The importance of providing the newborn infant with docosahexaenoic acid (DHA) from breast milk is well established. However, women in the United States, on average, have breast milk DHA levels of 0.20%, which is below the worldwide average (and proposed target) of >0.32%. Additionally, the relationship between maternal red blood cell (RBC) and breast milk DHA levels may provide insight into the sufficiency of DHA recommendations during lactation. Whether the standard recommendation of at least 200 mg/day of supplemental DHA during lactation is sufficient for most women to achieve a desirable RBC and breast milk DHA status is unknown.

METHODS

Lactating women (n = 27) at about 5 weeks postpartum were enrolled in a 10-12 week controlled feeding study that included randomization to 480 or 930 mg choline/d (diet plus supplementation). As part of the intervention, all participants were required to consume a 200 mg/d of microalgal DHA. RBC and breast milk DHA levels were measured by capillary gas chromatography in an exploratory analysis.

RESULTS

Median RBC DHA was 5.0% (95% CI: 4.3, 5.5) at baseline and 5.1% (4.6, 5.4) after 10 weeks of supplementation (P = 0.6). DHA as a percent of breast milk fatty acids increased from 0.19% (0.18, 0.33) to 0.34% (0.27, 0.38) after supplementation (P<0.05). The proportion of women meeting the target RBC DHA level of >5% was unchanged (52% at baseline and week 10). The proportion of women achieving a breast milk DHA level of >0.32% approximately doubled from 30% to 56% (p = 0.06). Baseline RBC and breast milk DHA levels affected their responses to supplementation. Those with baseline RBC and breast milk DHA levels above the median (5% and 0.19%, respectively) experienced no change or a slight decrease in levels, while those below the median had a significant increase. Choline supplementation did not significantly influence final RBC or breast milk DHA levels.

CONCLUSIONS

On average, the standard prenatal DHA dose of 200 mg/d did not increase RBC DHA but did increase breastmilk DHA over 10 weeks in a cohort of lactating women in a controlled-feeding study. Baseline DHA levels in RBC and breast milk affected the response to DHA supplementation, with lower levels being associated with a greater increase and higher levels with no change or a slight decrease. Additional larger, dose-response DHA trials accounting for usual intakes and baseline DHA status are needed to determine how to best achieve target breast milk DHA levels and to identify additional modifiers of the variable breast milk DHA response to maternal DHA supplementation.

Quantitating fatty acids in dried blood spots on a common collection card versus a novel wicking sampling device

Blood biomarkers of n - 3 polyunsaturated fatty acids can serve as indicators of dietary intake and benefits and/or disease risk. The use of dried blood spots for fatty acid analyses is increasing but most of the reported data is qualitative (relative percentages of total fatty acids). The ability to quantitate concentrations of fatty acids on a common blood spot collection card and a novel wicking device designed to collect 10 µL of blood was compared with a wet blood sample in ten young adult participants. Prior to this comparison, the collection materials were screened for contaminants by gas chromatography with flame ionization and liquid chromatography/tandem mass spectrometry, and the blood volume and blood spot area relationship of the collection card was confirmed using technical replicates. Palmitate and stearate were detected as free fatty acids on both collection materials and as lysophosphatidylcholines on the wicking device. The low amounts (<1.0 µg) did not affect the quantitation of these fatty acids in either material. The relationship between blood volume and blood spot area was linear (r = 0.99, p < 0.001) and it was determined that a 6 mm hole punch contained 9.6 µL of blood. When compared with wet blood, the fatty acid determinations from the dried blood spots were largely similar although there were some minor differences in low abundant fatty acids. Quantitative fatty acid determinations of dried blood spots are possible and should be reported along with relative percentage data to improve interpretation in the future.

Gestational age and maternal status of DHA and other polyunsaturated fatty acids in pregnancy: A systematic review

INTRODUCTION

Maternal diet is important in determining omega-3 DHA status however there is limited knowledge of other factors influencing maternal omega-3 concentrations during pregnancy. The primary objective of this systematic review and meta-analysis was to evaluate whether maternal DHA status changed across gestation. Changes in levels of other key polyunsaturated fatty acids were also investigated.

MATERIALS AND METHODS

The Medline, Embase, Amed, and CINAHL databases were searched. Included studies reported measures of maternal omega-3 status in at least two pregnancy trimesters.

RESULTS

Thirteen studies were included in the final analyses. Absolute omega-3 DHA concentrations increased across gestation, but decreased as a proportion of total lipids.

DISCUSSION

Our findings are consistent with previous observations of increases in lipid mobilisation, coupled with preferential transfer of DHA to the fetus, with advancing gestation. However the number of eligible studies was small and further investigations are required.

Exposure to a Farm Environment During Pregnancy Increases the Proportion of Arachidonic Acid in the Cord Sera of Offspring

Growing up in a farm environment is protective against allergy development. Various explanations have been put forward to explain this association. Fatty acids are regulators of immune function and the composition of fatty acids in the circulation system may affect immune development. Here, we investigate whether the fatty acid composition of cord serum differs for infants born to Farm (n = 26) or non-Farm mothers (n =29) in the FARMFLORA birth-cohort. For comparison, the levels of fatty acids in the maternal diet, serum and breast milk around 1 month post-partum were recorded. The fatty acids in the cord sera from infants born to Farm mothers had higher proportions of arachidonic acid (20:4 n-6) and adrenic acid (22:4 n-6) than those from infants born to non-Farm mothers. No differences were found for either arachidonic acid or adrenic acid in the diet, samples of the serum, or breast milk from Farm and non-Farm mothers obtained around 1 month post-partum. The arachidonic and adrenic acid levels in the cord blood were unrelated to allergy outcome for the infants. The results suggest that a farm environment may be associated with the fatty acid composition to which the fetus is exposed during pregnancy.

Concentrations of docosahexaenoic acid are reduced in maternal liver, adipose, and heart in rats fed high-fat diets without docosahexaenoic acid throughout pregnancy

Fetal accretion for DHA is high during late pregnancy due to the brain growth spurt. Prior evidence suggests that DHA is mobilized from maternal liver and adipose to meet fetal accretion and physiological requirements. However, changes in the DHA levels of various maternal tissues throughout pregnancy and into lactation of mothers on diets with and without dietary DHA, and with a background dietary fatty acid profile that resembles human intake has not been examined. Sprague Dawley rats were fed a total western diet with (TWD + ) or without DHA (TWD-) along with a commercial rodent chow control (Chow) throughout pregnancy and postpartum. The fatty acid compositions of adipose, brain, heart, liver, erythrocytes, and plasma were determined before pregnancy, at 15 and 20 days of pregnancy, and 7 days postpartum. The placenta, fetuses, and pups were also examined when available. Maternal DHA concentrations were increased in plasma at 20 days pregnancy in all the diets with TWD + > Chow > TWD-. Maternal DHA concentrations in the TWD- group were lower in adipose throughout pregnancy as compared with the other diets. At postpartum, DHA concentrations decreased below baseline levels in the heart of the TWD- and Chow dams and the liver of the TWD- dams. Whole body DHA concentrations of the fetuses did not differ but there was evidence of decreased DHA in the whole body and tissues of the TWD- and Chow 7d old pups. In conclusion, it appears that in this rodent model of pregnancy, maternal adaptations were made to meet fetal DHA requirements, but they may compromise maternal DHA status and the ability to deliver DHA during lactation.

Dynamic interactions of n-3 and n-6 fatty acid nutrients

Careful handling of data on fatty acid composition is needed when interpreting evidence for the influence of dietary n-3 and n-6 essential fatty acids on brain function and health conditions. The relative dietary supplies of competing n-3 and n-6 nutrients determine the balance of 20- and 22-carbon n-3 and n-6 highly unsaturated fatty acids (HUFA) which accumulate competitively at the 2-position of tissue phospholipids. In turn, the HUFA balance expressed as the %n-6 in HUFA affects the likely intensity of n-6 eicosanoid actions in diverse health conditions. As a result, measures of HUFA balance are important, valid biomarkers for designing and monitoring successful preventive nutrition interventions. Successful interventions must also consider the ability of fatty acid ligands to saturate binding sites of enzymes and receptors and give paradoxical dose-response results.

Validation of an equation predicting highly unsaturated fatty acid (HUFA) compositions of human blood fractions from dietary intakes of both HUFAs and their precursors

Proportions of omega-3 (n-3) and omega-6 (n-6) in 20- and 22-carbon highly unsaturated fatty acids with 3 or more double bonds (HUFA) accumulated in tissue HUFA (e.g., the %n-6 in HUFA) are biomarkers reflecting intakes of n-6 and n-3 fatty acids. An empirical equation, referred to here as the Lands' Equation, was developed previously to use dietary intakes of n-6 and n-3 HUFA and their 18-carbon precursors to estimate the %n-6 in HUFA of humans. From the PubMed database, we identified clinical trials reporting (a) dietary intake of at least linoleic acid (18:2n-6) and alpha-linolenic acid (18:3n-3), and (b) the amounts of at least arachidonic acid (20:4n-6), eicosapentaenoic acid (20:5n-3), and docosahexaenoic acid (22:6n-3) in lipids of plasma, serum, or red blood cell. Linear regression analyses comparing reported and predicted %n-6 in HUFA gave a correlation coefficient of 0.73 (p<0.000000) for 34 studies with 92 subject groups. These results indicate that circulating HUFA compositions can be reliably estimated from dietary intake data that not only includes n-3 and n-6 HUFA consumption, but also includes consumption of 18 carbon n-3 and n-6 precursor fatty acids.

Dietary ALA, EPA and DHA have distinct effects on oxylipin profiles in female and male rat kidney, liver and serum

There is much data on the effects of dietary n-3 fatty acids on tissue fatty acid compositions, but comparable comprehensive data on their oxygenated metabolites (oxylipins) is limited. The effects of providing female and male rats with diets high in α-linolenic acid (ALA), EPA or DHA for 6 weeks on oxylipins and fatty acids in kidney, liver and serum were therefore examined. The oxylipin profile generally reflected fatty acids, but it also revealed unique effects of individual n-3 fatty acids that were not apparent from fatty acid data alone. Dietary ALA increased renal and serum DHA oxylipins even though DHA itself did not increase, while dietary EPA did not increase DHA oxylipins in kidney or liver, suggesting that high EPA may inhibit this conversion. Oxylipin data generally corroborated fatty acid data that indicated that DHA can be retroconverted to EPA and that further retroconversion to ALA is limited. Dietary n-3 fatty acids decreased n-6 fatty acids and their oxylipins (except linoleic acid and its oxylipins), in order of effectiveness of DHA > EPA > ALA, with some exceptions: several arachidonic acid oxylipins modified at carbon 15 were not lower in all three sites, and EPA had a greater effect on 12-hydroxy-eicosatetraenoic acid and its metabolites in the liver. Oxylipins were predominantly higher in males, which was not reflective of fatty acids. Tissue-specific oxylipin profiles, therefore, provide further information on individual dietary n-3 fatty acid and sex effects that may help explain their unique physiological effects and have implications for dietary recommendations.

PEMT, Δ6 desaturase, and palmitoyldocosahexaenoyl phosphatidylcholine are increased in rats during pregnancy

DHA is important for fetal neurodevelopment. During pregnancy, maternal plasma DHA increases, but the mechanism is not fully understood. Using rats fed a fixed-formula diet (DHA as 0.07% total energy), plasma and liver were collected for fatty acid profiling before pregnancy, at 15 and 20 days of pregnancy, and 7 days postpartum. Phosphatidylethanolamine methyltransferase (PEMT) and enzymes involved in PUFA synthesis were examined in liver. Ad hoc transcriptomic and lipidomic analyses were also performed. With pregnancy, DHA increased in liver and plasma lipids, with a large increase in plasma DHA between day 15 and day 20 that was mainly attributed to an increase in 16:0/DHA phosphatidylcholine (PC) in liver (2.6-fold) and plasma (3.9-fold). Increased protein levels of Δ6 desaturase (FADS2) and PEMT at day 20 and increased Pemt expression and PEMT activity at day 15 suggest that during pregnancy, both DHA synthesis and 16:0/DHA PC synthesis are upregulated. Transcriptomic analysis revealed minor changes in the expression of genes related to phospholipid synthesis, but little insight on DHA metabolism. Hepatic PEMT appears to be the mechanism for increased plasma 16:0/DHA PC, which is supported by increased DHA biosynthesis based on increased FADS2 protein levels.

Dietary Intake and Omega-3 DHA Status in Pregnant Women Who Are Overweight

OBJECTIVE

To estimate dietary intake of pregnant women who are overweight, assess their omega-3 docosahexaenoic acid (DHA) status, and compare results between Black and White women.

DESIGN

Cross-sectional study with a longitudinal component (dietary assessment).

SETTING

Outpatient clinics at Woman's Hospital, Baton Rouge, Louisiana and telephone calls.

PARTICIPANTS

Pregnant women (N = 21) who were overweight (body mass index = 25.0-29.9 kg/m²).

METHODS

Repeated 24-hour dietary recalls using the University of Minnesota Nutrition Data System for Research were conducted to determine nutrient intakes. Red blood cell fatty acids were analyzed with gas chromatography to determine omega-3 DHA status. Descriptive statistics, one- and two-sample t tests, Fisher's exact tests, chi-square test, and analysis of covariance were used to analyze data.

RESULTS

On average, participants consumed 72 ± 63 mg omega-3 DHA/day. Age, race, and socioeconomic status did not affect the probability of achieving recommended omega-3 DHA dietary intake (p > .05). Black women had lower omega-3 DHA status (7.98 ± 0.94 weight percentage) than White women (9.29 ± 1.68 weight percentage; p ≤ .05).

CONCLUSION

Analysis of our data suggests a need for nutrition education regarding the benefits of omega-3 DHA consumption during pregnancy for women of childbearing age. The current finding warrants further exploration.

Conversion ratios of n-3 fatty acids between plasma and erythrocytes: a systematic review and meta-regression

As biomarkers of dietary intake or disease risk factor, n-3 fatty acid (FA) can be measured in plasma phospholipids (PL), total lipids (TL) or erythrocytes. However, the numeric relationships between n-3 FA in these lipid pools are not clear. Our goal was to derive conversion ratios for plasma and erythrocyte n-3 FA. Potential studies were identified through systematic literature search in PubMed, Embase and the Cochrane Library of Systematic reviews (1950 to October 2014). In all, fifty-six studies reporting n-3 in healthy individuals were included, of which thirty-four articles reported plasma PL and erythrocytes, and twenty-two reported plasma TL and erythrocytes. Meta-regressions were performed to quantify the ratio between plasma and erythrocyte n-3 FA weight percentages, controlling for covariates including age, sex and study design. The conversion ratios from plasma PL to erythrocytes for EPA, DHA, DPA and total n-3 PUFA are 0·75, 1·16, 2·32 and 1·22; the corresponding conversion ratios from plasma TL to erythrocytes are 1·00, 2·10, 3·85 and 2·08, respectively. The conversion ratios were validated using reported values from the literature and measured data from fifty individuals. The relative error of the predicted results were within 10 % of the mean reported values except for EPA, and the individual measured data except for DPA, in plasma TL. The conversion ratios between plasma PL and erythrocytes were more stable compared with plasma TL. Such conversion ratios will be useful for nutritionists or public health professionals to assess FA profiles of different populations using data collected with different methodologies.

Effects of the flavonol quercetin and α-linolenic acid on n-3 PUFA status in metabolically healthy men and women: a randomised, double-blinded, placebo-controlled, crossover trial

Increased dietary intake and tissue status of the long-chain n-3 PUFA, EPA and DHA, is associated with cardiovascular benefits. Epidemiological and animal studies suggest that concomitant nutritive intake of flavonoids may increase the conversion of α-linolenic acid (ALA) to longer-chain n-3 fatty acids EPA and DHA. We investigated the effects of increased ALA intake on fatty acid composition of serum phospholipids and erythrocytes in metabolically healthy men and women and whether fatty acid profiles and ALA conversion were affected by regular quercetin intake or sex. Subjects (n 74) were randomised to receive at least 3·3 g/d ALA with either 190 mg/d quercetin (ALA+quercetin) or placebo (ALA+placebo) in a double-blinded, placebo-controlled, crossover trial with 8-week intervention periods separated by an 8-week washout period. A total of seven subjects dropped out for personal reasons. Data from the remaining sixty-seven subjects (thirty-four males and thirty-three females) were included in the analysis. Both interventions significantly increased serum phospholipid ALA (ALA+placebo: +69·3 %; ALA+quercetin: +55·8 %) and EPA (ALA+placebo: +37·3 %; ALA+quercetin: +25·5 %). ALA + quercetin slightly decreased DHA concentration by 9·3 %. Erythrocyte ALA and EPA significantly increased with both interventions, whereas DHA decreased. Fatty acid composition did not differ between sexes. We found no effect of quercetin. Intake of 3·6 g/d ALA over an 8-week period resulted in increased ALA and EPA, but not DHA, in serum phospholipids and erythrocytes. Neither quercetin supplementation nor sex affected the increment of ALA and relative proportions of n-3 PUFA in serum phospholipids and erythrocytes.

Polyunsaturated Fatty Acid Levels in Maternal Erythrocytes of Japanese Women during Pregnancy and after Childbirth

Background: The transport of polyunsaturated fatty acids (PUFAs), such as arachidonic acid (ARA, 20:4n-6) and docosahexaenoic acid (DHA, 22:6n-3), to the fetus from maternal stores increases depending on the fetal requirements for PUFA during the last trimester of pregnancy. Therefore, maternal blood PUFA changes physiologically with gestational age. However, the changes in PUFA levels in maternal blood erythrocytes during pregnancy and after childbirth have not been fully investigated in a fish-eating population. Objective: To examine the changes of ARA and DHA levels in maternal erythrocytes with the progress of pregnancy and the relationship between maternal and umbilical cord erythrocyte PUFA levels in pregnant Japanese women who habitually eat fish and shellfish. Design: This study was performed as a part of the adjunct study of the Japan Environment and Children’s Study (JECS). The participants were 74 pregnant women. The maternal blood samples were collected at 27, 30, and 36 weeks of pregnancy, and 2 days and 1 month after delivery, and umbilical cord blood was collected at delivery. The fatty acid levels of erythrocytes in these blood samples were determined. Results: ARA and DHA levels in maternal erythrocytes tended to decrease with the progress of pregnancy. While the DHA level decreased further after delivery, the ARA level returned to the value at 27 weeks of pregnancy within 1 month after delivery. The n-3 and n-6 PUFA levels in maternal erythrocytes at 27, 30, and 36 weeks of pregnancy were significantly positively correlated with the corresponding fatty acid levels in umbilical cord erythrocytes. Conclusion: The present findings showed a significant change in erythrocyte PUFA levels during pregnancy and after childbirth in a fish-eating population. The PUFA levels of maternal blood after the second trimester may be a reliable marker for predicting PUFA levels in infants’ circulating blood.

Fish Oil-Derived Fatty Acids in Pregnancy and Wheeze and Asthma in Offspring

BACKGROUND

Reduced intake of n-3 long-chain polyunsaturated fatty acids (LCPUFAs) may be a contributing factor to the increasing prevalence of wheezing disorders. We assessed the effect of supplementation with n-3 LCPUFAs in pregnant women on the risk of persistent wheeze and asthma in their offspring.

METHODS

We randomly assigned 736 pregnant women at 24 weeks of gestation to receive 2.4 g of n-3 LCPUFA (fish oil) or placebo (olive oil) per day. Their children formed the Copenhagen Prospective Studies on Asthma in Childhood₂₀₁₀ (COPSAC₂₀₁₀) cohort and were followed prospectively with extensive clinical phenotyping. Neither the investigators nor the participants were aware of group assignments during follow-up for the first 3 years of the children's lives, after which there was a 2-year follow-up period during which only the investigators were unaware of group assignments. The primary end point was persistent wheeze or asthma, and the secondary end points included lower respiratory tract infections, asthma exacerbations, eczema, and allergic sensitization.

RESULTS

A total of 695 children were included in the trial, and 95.5% completed the 3-year, double-blind follow-up period. The risk of persistent wheeze or asthma in the treatment group was 16.9%, versus 23.7% in the control group (hazard ratio, 0.69; 95% confidence interval [CI], 0.49 to 0.97; P=0.035), corresponding to a relative reduction of 30.7%. Prespecified subgroup analyses suggested that the effect was strongest in the children of women whose blood levels of eicosapentaenoic acid and docosahexaenoic acid were in the lowest third of the trial population at randomization: 17.5% versus 34.1% (hazard ratio, 0.46; 95% CI, 0.25 to 0.83; P=0.011). Analyses of secondary end points showed that supplementation with n-3 LCPUFA was associated with a reduced risk of infections of the lower respiratory tract (31.7% vs. 39.1%; hazard ratio, 0.75; 95% CI, 0.58 to 0.98; P=0.033), but there was no statistically significant association between supplementation and asthma exacerbations, eczema, or allergic sensitization.

CONCLUSIONS

Supplementation with n-3 LCPUFA in the third trimester of pregnancy reduced the absolute risk of persistent wheeze or asthma and infections of the lower respiratory tract in offspring by approximately 7 percentage points, or one third. (Funded by the Lundbeck Foundation and others; ClinicalTrials.gov number, NCT00798226 .).

Both maternal and offspring Elovl2 genotypes determine systemic DHA levels in perinatal mice

The molecular details relevant to dietary supplementation of the omega-3 fatty acid DHA in mothers as well as in their offspring are not clear. The PUFA elongase, elongation of very long-chain fatty acid (ELOVL)2, is a critical enzyme in the formation of DHA in mammals. In order to address the question regarding the origin of DHA during perinatal life, we have used DHA-deficient Elovl2-ablated mice as a model system to analyze the maternal impact on the DHA level in their offspring of various genotypes. Elovl2^-/- mothers maintained on control diet had significantly lower systemic levels of DHA compared with the Elovl2^+/- and Elovl2^+/+ mothers. Dietary DHA administration during the pregnancy and lactation periods led to increased DHA accretion in maternal tissues and serum of all genotypes. The proportion of DHA in the liver and serum of the Elovl2^-/- offspring was significantly lower than in the Elovl2^+/+ offspring. Remarkably, the DHA level in the Elovl2^+/- offspring nursed by DHA-free-fed Elovl2^-/- mothers was almost as high as in +/+ pups delivered by +/+ mothers, suggesting that endogenous synthesis in the offspring can compensate for maternal DHA deficiency. Maternal DHA supplementation had a strong impact on offspring hepatic gene expression, especially of the fatty acid transporter, Mfsd2a, suggesting a dynamic interplay between DHA synthesis and DHA uptake in the control of systemic levels in the offspring.

Reproductive stage associated changes in plasma fatty acid profile and proinflammatory cytokine expression in rat mammary glands

Mastitis is a common disease for mammals all around the world. Figuring out why mastitis mainly occurs around parturition may be helpful for dealing with the disease. Lipolytic activity and oxidative stress take place around parturition, which may leads to alteration in fatty acids profile and proinflammatory cytokine expression. Thus, the aim of the present study was to further our understanding about the high incidence of mastitis around parturition by comparison of plasma fatty acid profile and mammary inflammation indicators at different reproductive stages. A total of 47 female rats were included in the present study. After mating, all the pregnant and non-pregnant rats began to receive the same experimental diet. Blood samples were collected at day 1 and 14 of gestation as well as day 3 postpartum. Mammary samples were collected at day 14 of gestation and day 3 postpartum from pregnant and non-pregnant rats. The results showed that rats at d 3 postpartum had greater (P < 0.05) plasma concentrations of non-esterified fatty acids (NEFA), arachidonic acid (ARA) and docosahexaenoic acid (DHA) as well as ARA: eicosapentaenoic acid (EPA) ratio than those at d 14 of gestation. The mRNA abundances of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), IL-8 and xanthine oxidoreductase (XOR) in mammary of the pregnant rats were greater (P < 0.05) than those in age-matched non-pregnant rats. Rats at d 3 postpartum had higher (P < 0.05) protein expression levels of IL-1β and TNF-α as well as meloperoxidase (MPO) activity and polymorphonuclear neutrophils (PMN) prevalence than those at d 1 of gestation. The rats at d 3 postpartum also had greater (P < 0.05) IL-1β and MPO activity than those at d 14 of gestation. The results indicated that elevated mammary expression of proinflammatory cytokines and XOR as well as altered fatty acid profile around parturition might facilitate the recruitment of neutrophils into mammary glands.

Global survey of the omega-3 fatty acids, docosahexaenoic acid and eicosapentaenoic acid in the blood stream of healthy adults

Studies reporting blood levels of the omega-3 polyunsaturated fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), were systematically identified in order to create a global map identifying countries and regions with different blood levels. Included studies were those of healthy adults, published in 1980 or later. A total of 298 studies met all inclusion criteria. Studies reported fatty acids in various blood fractions including plasma total lipids (33%), plasma phospholipid (32%), erythrocytes (32%) and whole blood (3.0%). Fatty acid data from each blood fraction were converted to relative weight percentages (wt.%) and then assigned to one of four discrete ranges (high, moderate, low, very low) corresponding to wt.% EPA+DHA in erythrocyte equivalents. Regions with high EPA+DHA blood levels (>8%) included the Sea of Japan, Scandinavia, and areas with indigenous populations or populations not fully adapted to Westernized food habits. Very low blood levels (≤4%) were observed in North America, Central and South America, Europe, the Middle East, Southeast Asia, and Africa. The present review reveals considerable variability in blood levels of EPA+DHA and the very low to low range of blood EPA+DHA for most of the world may increase global risk for chronic disease.

Increased ω-3 polyunsaturated fatty acid/arachidonic acid ratios and upregulation of signaling mediator in individuals with autism spectrum disorders

AIMS

The investigation of links between the ratio of omega-3/omega-6 PUFAs and neuronal signaling is a research priority in autism spectrum disorders (ASD).

MAIN METHODS

We examine the relationships between the plasma ratios of docosahexaenoid acid (DHA)/arachidonic acid (AA) and eicopentaenoic acid (EPA)/AA and biomarkers of AA-related signaling mediators such as ceruloplasmin, transferrin and superoxide dismutase, in the behavioral symptoms of 28 individuals with ASD (mean age 13.5±4.6years) and 21 age- and gender-matched normal healthy controls (mean age 13.9±5.7years). Behavioral symptoms were assessed using the Aberrant Behavior Checklists (ABC). We conducted controlling for dietary intake and assessed the dietary intake of nutrients.

KEY FINDINGS

There were no significant differences in intake of nutrients such as omega-3 and omega-6 PUFAs, saturated and unsaturated fatty acid, DHA, AA, iron and copper. Plasma EPA, DHA, and arachidic acid levels, and plasma DHA/AA and EPA/AA ratios were significantly higher, while plasma AA and adrenic acid were significantly lower in the 28 individuals with ASD than in the 21 normal controls. The ABC scores were significantly higher in the ASD group compared to the control group. The plasma ceruloplasmin levels in the ASD group were significantly reduced compared to those in the control group.

SIGNIFICANCE

Increased plasma DHA/AA and EPA/AA ratios may be related to low plasma levels of ceruloplasmin which has neuroprotective properties. Reduced plasma ceruloplasmin levels may diminish the protective capacity against brain damage, and may contribute to the pathophysiology of behavioral symptoms in individuals with ASD.

DHA in Pregnant and Lactating Women from Coastland, Lakeland, and Inland Areas of China: Results of a DHA Evaluation in Women (DEW) Study

Few studies have examined docosahexaenoic acid (DHA) in pregnant and lactating women in developing countries like China, where DHA-enriched supplements are increasingly popular. We aimed to assess the DHA status among Chinese pregnant and lactating women residing areas differing in the availability of aquatic products. In total, 1211 women in mid-pregnancy (17 ± 2 weeks), late pregnancy (39 ± 2 weeks), or lactation (42 ± 7 days) were enrolled from Weihai (coastland), Yueyang (lakeland), and Baotou (inland) city, with approximately 135 women in each participant group by region. DHA concentrations were measured using capillary gas chromatography, and are reported as weight percent of total fatty acids. Mean plasma DHA concentrations were higher in coastland (mid-pregnancy 3.19%, late pregnancy 2.54%, lactation 2.24%) and lakeland women (2.45%, 1.95%, 2.26%) than inland women (2.25%, 1.67%, 1.68%) (p values < 0.001). Similar differences were observed for erythrocyte DHA. We conclude that DHA concentrations of Chinese pregnant and lactating women are higher in coastland and lakeland regions than in inland areas. DHA status in the study population appears to be stronger than populations from other countries studied to date.

Fasting enriches liver triacylglycerol with n-3 polyunsaturated fatty acids: implications for understanding the adipose-liver axis in serum docosahexaenoic acid regulation

We investigated the effect of short-term fasting on coordinate changes in the fatty acid composition of adipose triacylglycerol (TAG), serum non-esterified fatty acids (NEFA), liver TAG, and serum TAG and phospholipids in mice fed ad libitum or fasted for 16 h overnight. In contrast to previous reports under conditions of maximal lipolysis, adipose tissue TAG was not preferentially depleted of n-3 PUFA or any specific fatty acids, nor were there any striking changes in the serum NEFA composition. Short-term fasting did, however, increase the hepatic proportion of n-3 PUFA, and almost all individual species of n-3 PUFA showed relative and absolute increases. The relative proportion of n-6 PUFA in liver TAG also increased but to a lesser extent, resulting in a significant decrease in the n-6:n-3 PUFA ratio (from 14.3 ± 2.54 to 9.6 ± 1.20), while the proportion of MUFA decreased significantly and SFA proportion did not change. Examination of genes involved in PUFA synthesis suggested that hepatic changes in the elongation and desaturation of precursor lipids could not explain this effect. Rather, an increase in the expression of fatty acid transporters specific for 22:6n-3 and other long-chain n-3 and n-6 PUFA likely mediated the observed hepatic enrichment. Analysis of serum phospholipids indicated a specific increase in the concentration of 22:6n-3 and 16:0, suggesting increased specific synthesis of DHA-enriched phospholipid by the liver for recirculation. Given the importance of blood phospholipid in distributing DHA to neural tissue, these findings have implications for understanding the adipose-liver-brain axis in n-3 PUFA metabolism.

Dietary micronutrient intake during pregnancy is a function of carbohydrate quality

BACKGROUND

Despite normal gestational weight gain, dietary studies in pregnant women show intakes below the recommendations for energy and micronutrients.

OBJECTIVE

This study compared changes in dietary intake from the second to third trimester with emphasis on energy intake and carbohydrate quality.

DESIGN

These post hoc analyses were based on 566 women participating in the Pregnancy and Glycemic Index Outcomes study, a randomized controlled trial comparing the effect of low-glycemic index (GI) dietary advice with healthy eating advice on selected pregnancy outcomes. With the use of multilevel mixed-regression analysis, changes in total energy intake, starch, sugar, fiber intake, GI, and glycemic load (GL) were correlated with intake of different micronutrients.

RESULTS

Energy intake decreased in the third trimester, and most women did not meet the national recommended amounts for iron, folate, and dietary fiber from food sources alone. After adjustment for age, ethnicity, prepregnancy body mass index, and intervention group, change in energy intake was positively related to change in intake of all micronutrients (P < 0.001). GI, GL, and starch intake were inversely related to micronutrient intake (P < 0.001), whereas higher total sugars predicted higher intake (P < 0.001). Associations with dietary fiber were inconsistent.

CONCLUSIONS

Normal pregnancy can be associated with a decline in energy and micronutrient intake from diet. Low dietary GI and GL were the best predictors of a favorable micronutrient profile. This trial was registered at www.anzctr.org.au as ACTRN12610000174088.

Modulation of prenatal stress via docosahexaenoic acid supplementation: implications for child mental health

Pregnant women living in poverty experience chronic and acute stressors that may lead to alterations in circulating glucocorticoids. Experimental evidence from animal models and correlational studies in humans support the hypothesis that prenatal exposure to high levels of glucocorticoids can negatively affect the developing fetus and later emotional and behavioral regulation in the offspring. In this integrative review, recent findings from research in psychiatry, obstetrics, and animal and human experimental studies on the role of docosahexaenoic acid in modulation of the stress response and brain development are discussed. The potential for an emerging field of nutritionally based perinatal preventive interventions for improving offspring mental health is described. Prenatal nutritional interventions may prove to be effective approaches to reducing common childhood mental disorders.

Association between fatty acid supplementation and prenatal stress in African Americans: a randomized controlled trial

OBJECTIVE

To test the association between docosahexaenoic acid (DHA) supplementation and perceived stress and cortisol response to a stressor during pregnancy in a sample of African American women living in low-income environments.

METHODS

Sixty-four African American women were enrolled at 16-21 weeks of gestation. Power calculations were computed using published standard deviations for the Perceived Stress Scale and the Trier Social Stress Test. Participants were randomized to either 450 mg per day of DHA (n=43) or placebo (n=21). At baseline and at 24 and 30 weeks of gestation, perceived stress was assessed by self-report. Cortisol response to a controlled stressor, the Trier Social Stress Test was measured from saliva samples collected upon arrival to the laboratory and after the completion of the Trier Social Stress Test.

RESULTS

Women in the DHA supplementation group reported lower levels of perceived stress at 30 weeks of gestation, controlling for depression and negative life events (mean 27.4 compared with 29.5, F [3, 47] 5.06, P=.029, Cohen's d=0.65). Women in the DHA supplementation had lower cortisol output in response to arriving to the laboratory and a more modulated response to the stressor (F [1.78, 83.85] 6.24, P=.004, Cohen's d=0.76).

CONCLUSION

Pregnant women living in urban low-income environments who received DHA reported reduced perceived stress and lower levels of stress hormones in the third trimester. Docosahexaenoic acid supplementation may be a method for attenuating the effects of maternal stress during late pregnancy and improving the uterine environment with regard to fetal exposure to glucocorticoids.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, www.clinicaltrials.gov, NCT01158976.

Treatment of ovariectomized rats with 17β-estradiol increases hepatic delta-6 desaturase enzyme expression and docosahexaenoic acid levels in hepatic and plasma phospholipids

Higher docosahexaenoic acid (DHA) in females compared with males suggests ovarian hormones increase DHA production. Eight-week old rats were ovariectomized or sham operated (SHAM), and ovariectomized rats were treated with implanted pellets providing 17β-estradiol (OVX+E), progesterone (OVX+P), both (OVX+PE) or neither (OVX) for 14 days. Immunoblot and fatty acid analysis were performed on all samples, and microarray analysis was performed on OVX and SHAM groups. Increased Δ6-desaturase in OVX relative to SHAM was observed by microarray (12% higher) and immunoblot (31% higher). OVX+E and OVX+PE rats had 39% and 42% higher Δ6-desaturase content, respectively, compared with OVX. OVX+E and OVX+PE also increased phospholipid DHA concentrations in liver (increase of 34% and 40%, respectively) and plasma (increase of 70% and 74%, respectively) relative to OVX. Progesterone exerted no effect on Δ6-desaturase or DHA. These results indicate that 17β-estradiol increases DHA through increased Δ6-desaturase, possibly explaining sex differences in DHA.

Stearoyl-CoA desaturase 1, elongase 6 and their fatty acid products and precursors are altered in ovariectomized rats with 17β-estradiol and progesterone treatment

Sex differences in monounsaturated fatty acid (MUFA) levels suggest ovarian hormones may affect MUFA biosynthesis. Sprague-Dawley rats (8 weeks of age) were ovariectomized or sham operated with ovariectomized rats implanted with a constant-release hormone pellet providing 17β-estradiol, progesterone, both or neither at 10 weeks of age. After 14 days, rats were fasted overnight and sacrificed to collect plasma and livers for analysis. Hepatic stearoyl-CoA desaturase (SCD1) expression was unchanged between ovariectomized and sham controls, as determined by microarray and immunoblotting. However, SCD1 protein was increased in rats treated with estradiol plus progesterone. Elongase 6 protein levels were increased with 17β-estradiol treatment compared with sham. Rats treated with 17β-estradiol and 17β-estradiol plus progesterone had increased 16:0, 18:0, 16:1n-7 and 18:1n-7 in hepatic and plasma phospholipids. Ovarian hormones appear to be involved with MUFA biosynthesis, but the relationship appears complex and involves elongase 6 and SCD1.

Plasticity of mouse brain docosahexaenoic acid: modulation by diet and age

Decreases in brain docosahexaenoic acid (DHA) have been associated with losses in brain function leading to an interest in the conditions which lead to such brain decreases, and such variables as age. Also of relevance would be the rate of repletion of DHA when the n-3 dietary deficiency is reversed. This experiment describes dietary deficiency in n-3 fatty acids induced in weanling (3 week) and young adult (7 week) mice. There was an immediate and continuous loss of brain DHA with similar rates in the two age groups. Serum DHA declined more rapidly in younger animals with respect to similarly treated adults. Brain and serum docosapentaenoic acid (DPAn-6) increased more rapidly and to higher levels in the younger animals. A second experiment determined the rates of normalization of brain fatty acid profiles when alpha-linolenic acid was added to the diets of n-3 deficient mice. Brain DHA recovery occurred at a faster rate (half-time, T 1/2 = 1.4 weeks) when begun at weaning relative to young adult mice (T 1/2 = 3.5 weeks). Correspondingly, brain DPAn-6 recovered faster in the younger animals; the adult group had a half-time of more than twice that of the 3-week old group. This study therefore demonstrates that the young adult mouse brain DHA is somewhat plastic and can be partially depleted via a low n-3 fatty acid diet and subsequently restored when dietary n-3 fatty acids are repleted. Relevance of these findings for human nutrition is discussed.

A systematic review and meta-analysis of micronutrient intakes during pregnancy in developed countries

Micronutrient status during pregnancy influences maternal and fetal health, birth outcomes, and the risk of chronic disease in offspring. Research reporting dietary intake during pregnancy in nationally representative population samples, however, is limited. This review summarizes the micronutrient intakes of pregnant women from developed countries and compares them with relevant national recommendations. A systematic search without date limits was conducted. All studies reporting the micronutrient intakes of pregnant women were considered, irrespective of design. Two authors independently identified studies for inclusion and assessed methodological quality. Nutritional adequacy was summarized, with confounding factors considered. Meta-analysis data are reported for developed countries collectively, by geographical region, and by dietary methodology. Pregnant women in developed countries are at risk of suboptimal micronutrient intakes. Folate, iron, and vitamin D intakes were consistently below nutrient recommendations in each geographical region, and calcium intakes in Japan were below the Japanese recommendations and the average intake levels in other developed countries. Research examining the implications of potential nutrient insufficiency on maternal and offspring health outcomes is needed along with improvements in the quality of dietary intake reporting.

Tissue-specific sex differences in docosahexaenoic acid and Δ6-desaturase in rats fed a standard chow diet

Docosahexaenoic acid (DHA, 22:6n-3) is higher in the blood and tissues of females relative to males, but the underlying mechanism is not clear. The present study examined the expression of enzymes involved in the biosynthesis of DHA from short-chain n-3 polyunsaturated fatty acids in male and female rats (n = 6 for each sex). Rats were maintained on an AIN-93G diet and sacrificed at 14 weeks of age after an overnight fast. Plasma, erythrocytes, liver, heart, and brain were collected for fatty acid composition analysis and the determination of enzyme and transcription factor expression by RT-PCR and immunoblotting. Females had higher DHA concentrations in the total lipids of liver, plasma, erythrocyte, and heart (53%, 75%, 36%, and 25% higher, respectively, compared with males) with no sex differences in brain DHA concentrations. The mRNA content of Δ5-desaturase, Δ6-desaturase, and elongase 2 was 1.0-, 1.4-, and 1.1-fold higher, respectively, in the livers of female rats compared with males, with no differences in the hearts or brains. The protein content of Δ6-desaturase was also higher in females. Higher hepatic mRNA of sterol-regulatory element-binding protein 1-c and estrogen receptor α in the females suggests that lipogenic and estrogen signaling mechanisms are involved. The sex difference in DHA concentration is tissue specific and is associated with higher Δ6-desaturase expression in females relative to males, which appears to be limited to the liver.

Consequences of essential fatty acids

Essential fatty acids (EFA) are nutrients that form an amazingly large array of bioactive mediators that act on a large family of selective receptors. Nearly every cell and tissue in the human body expresses at least one of these receptors, allowing EFA-based signaling to influence nearly every aspect of human physiology. In this way, the health consequences of specific gene-environment interactions with these nutrients are more extensive than often recognized. The metabolic transformations have similar competitive dynamics for the n-3 and n-6 homologs when converting dietary EFA from the external environment of foods into the highly unsaturated fatty acid (HUFA) esters that accumulate in the internal environment of cells and tissues. In contrast, the formation and action of bioactive mediators during tissue responses to stimuli tend to selectively create more intense consequences for n-6 than n-3 homologs. Both n-3 and n-6 nutrients have beneficial actions, but many common health disorders are undesired consequences of excessive actions of tissue n-6 HUFA which are preventable. This review considers the possibility of preventing imbalances in dietary n-3 and n-6 nutrients with informed voluntary food choices. That action may prevent the unintended consequences that come from eating imbalanced diets which support excessive chronic actions of n-6 mediators that harm human health. The consequences from preventing n-3 and n-6 nutrient imbalances on a nationwide scale may be very large, and they need careful evaluation and implementation to avoid further harmful consequences for the national economy.

Systematic review and meta-analysis of energy and macronutrient intakes during pregnancy in developed countries

Research reporting diet during pregnancy in nationally representative samples is limited. This review summarizes the dietary intakes of pregnant women in developed countries and compares them with national recommendations. A systematic search without date limits was conducted. All studies reporting the macronutrient intakes of pregnant women were considered, irrespective of design. Two authors independently identified the studies to be included and assessed the methodological quality. Nutritional adequacy was summarized, with confounding factors considered. Meta-analysis data are reported for developed countries collectively, by geographical region, and by dietary methodology. Energy and macronutrient intakes of pregnant women do not match national recommendations. Energy and fiber intakes were consistently below recommendations, while total fat and saturated fat intakes were generally above recommendations and carbohydrate and polyunsaturated fat intakes were below to borderline low compared with recommendations. A mismatch between dietary practices and macronutrient recommendations in pregnant women is widespread and not well quantified. The implications of these practices are unknown until further research compares maternal diet with short-term and long-term maternal and offspring health outcomes.

Serum long chain n-3 fatty acids (EPA and DHA) in the pregnant mother are independent of risk of type 1 diabetes in the offspring

BACKGROUND

This article aims to study whether higher proportions of the long chain n-3 fatty acids eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) in the phospholipid fraction of serum samples in pregnancy were associated with a lower risk of childhood onset type 1 diabetes in the offspring.

METHODS

In a prospective cohort of nearly 30 000 pregnant women who gave birth in Norway during 1992-1994, we analysed serum samples from 89 women whose child developed type 1 diabetes and was included in the nationwide Norwegian Childhood Diabetes Registry and 125 randomly selected women whose child did not develop type 1 diabetes before 15 years of age. Specific fatty acids were expressed as the proportion of total fatty acids (g/100 g) in the phospholipid fraction in serum analysed using solid phase extraction and gas chromatography with flame ionization detection.

RESULTS

There was no significant association between EPA or DHA in maternal serum and risk of type 1 diabetes in the offspring. Odds ratio (OR) for upper versus lower quartile of EPA was 0.75 [95% confidence interval (CI) 0.34-1.65], test for trend p = 0.4, and for DHA OR = 0.71 (95% CI 0.33-1.53), test for trend p = 0.6. No significant association was found for the sum of n-3 fatty acids, or for n-6/n-3 ratio in the mother with risk of type 1 diabetes in the offspring.

CONCLUSIONS

Our data did not support the hypothesis that higher proportions of maternal EPA or DHA during pregnancy are associated with a lower risk of type 1 diabetes in the offspring.

EPA and DHA--protein, not fat is "where it's at"?

Guidelines and recommendations for the dietary intake of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are topics of debate. Recently, EPA and DHA intakes have been demonstrated to be associated with dietary protein intakes and not dietary fat intakes that are distinct from α-linolenic acid. We presently confirm these observations in a secondary analysis of baseline dietary intake data for the validation of a food frequency questionnaire (n=99). DHA intakes measured by both 3 d dietary record and food frequency questionnaire and EPA intakes measured by food frequency questionnaire were positively correlated with protein intakes. EPA and DHA were not associated with fat intakes in either assessment, while ?-linolenic acid was positively correlated with fat intakes. Future recommendations regarding the intake of omega-3 polyunsaturated fatty acids, and EPA and DHA specifically, should consider these associations that provide insight on dietary sources of EPA and DHA in the food supply.

Differences in preterm and term milk fatty acid compositions may be caused by the different hormonal milieu of early parturition

INTRODUCTION

The hormonal milieus of pregnancy and lactation are driving forces of nutrient fluxes supporting infant growth and development. The decrease of insulin sensitivity with compensatory hyperinsulinemia with advancing gestation, causes adipose tissue lipolysis and hepatic de novo lipogenesis (DNL).

SUBJECTS AND METHODS

We compared fatty acid (FA) contents and FA-indices for enzyme activities between preterm (28-36 weeks) and term (37-42) milks, and between colostrum (2-5 days), transitional (6-15) and mature (16-56) milks. We interpreted FA differences between preterm and term milks, and their changes with lactation, in terms of the well known decrease of insulin sensitivity during gestation and its subsequent postpartum restoration, respectively.

RESULTS

Compared with term colostrum, preterm colostrum contained higher indices of DNL in the breast (DNL-breast) and medium chain saturated-FA (MCSAFA), and lower DNL-liver and monounsaturated-FA (MUFA). Preterm milk also had higher docosahexaenoic acid (DHA) in colostrum and transitional milk and higher arachidonic acid (AA) in mature milk. Most preterm-term differences vanished with advancing lactation. In both preterm and term milks, DNL-breast and MCSAFA increased with advancing lactation, while DNL-liver, MUFA, long chain SAFA and AA decreased. DHA decreased in term milk. MUFA was inversely related to MCSAFA in all samples, correlated inversely with PUFA in colostrum and transitional milks, but positively in mature milk. MCSAFA correlated inversely with PUFA in mature milk.

CONCLUSION

Higher maternal insulin sensitivity at preterm birth may be the cause of lower MUFA (a proxy for DNL-liver) and higher MCSAFA (a proxy for DNL-breast) in preterm colostrum, compared with term colostrum. Restoring insulin sensitivity after delivery may be an important driving force for milk FA-changes in early lactation.

Postpartum changes in maternal and infant erythrocyte fatty acids are likely to be driven by restoring insulin sensitivity and DHA status

INTRODUCTION

Perinatal changes in maternal glucose and lipid fluxes and de novo lipogenesis (DNL) are driven by hormones and nutrients. Docosahexaenoic acid (DHA) reduces, whereas insulin augments, nuclear abundance of sterol-regulatory-element-binding-protein-1 (SREBP-1), which promotes DNL, stearoyl-CoA-desaturase (SCD, also Δ9-desaturase), fatty acid-(FA)-elongation (Elovl) and FA-desaturation (FADS). Decreasing maternal insulin sensitivity with advancing gestation and compensatory hyperinsulinemia cause augmented postprandial glucose levels, adipose tissue lipolysis and hepatic glucose- and VLDL-production. Hepatic VLDL is composed of dietary, body store and DNL derived FA. Decreasing insulin sensitivity increases the contribution of FA from hepatic-DNL in VLDL-triacylglycerols, and consequently saturated-FA and monounsaturated-FA (MUFA) in maternal serum lipids increase during pregnancy. Although other authors described changes in maternal serum and RBC essential-FA (EFA) after delivery, none went into detail about the changes in non-EFA and the mechanisms behind -and/or functions of- the observed changes.

HYPOTHESIS

Postpartum FA-changes result from changing enzymatic activities that are influenced by the changing hormonal milieu after delivery and DHA-status.

EMPIRICAL DATA

We studied FA-profiles and FA-ratios (as indices for enzymatic activities) of maternal and infant RBC at delivery and after 3 months exclusive breastfeeding in three populations with increasing freshwater-fish intakes. DNL-, SCD- and FADS2-activities decreased after delivery. Elongation-6 (Elovl-6)- and FADS1-activities increased. The most pronounced postpartum changes for mothers were increases in 18:0, linoleic (LA), arachidonic acid (AA) and decreases in 16:0, 18:1ω9 and DHA; and for infants increases in 18:1ω9, 22:5ω3, LA and decreases in 16:0 and AA. Changes were in line with the literature.

DISCUSSION

Postpartum increases in 18:0, and decreases in 16:0 and 18:1ω9, might derive from reduced insulin-promoted DNL-activity, with more reduced SCD- than Elovl-activity that leaves more 16:0 to be converted to 18:0 (Elovl-activity) than to MUFA (SCD-activity). Postpartum changes in ΣDNL, saturated-FA and MUFA related negatively to RBC-DHA. This concurs with suppression of both SCD- and Elovl-6 activities by DHA, through its influence on SREBP. Infant MUFA and LA increased at expense of their mothers. Sustained transport might be important for myelination (MUFA) and skin barrier development (LA). Maternal postpartum decreases in FADS2-, and apparent increases in FADS1-activity, together with increases in LA, AA, and 22:5ω3, but decrease in DHA, confirm that FADS2 is rate limiting in EFA-desaturation. Maternal LA and AA increases might be the result of rerouting from transplacental transfer to the incorporation into milk lipids and discontinued placental AA-utilization.

IMPLICATIONS

Perinatal changes in maternal and infant FA status may be strongly driven by changing insulin sensitivity and DHA status.

Validity of the T-ACE in pregnancy in predicting child outcome and risk drinking

Preventing fetal alcohol spectrum disorders (FASDs) requires detection of in-pregnancy maternal risk drinking. The widely used T-ACE screen has been applied in various ways, although the impact of those different uses on effectiveness is uncertain. We examined relations among different T-ACE scoring criteria, maternal drinking, and child outcome. Self-reported across-pregnancy maternal drinking was assessed in 75 African-American women. The different T-ACE criteria used varied the level of drinking that defined tolerance (two or three drinks) and the total T-ACE score cut-points (two or three). Receiver operator curves and regression analysis assessed the significance of relations. Increasing the total T-ACE score cut-point to 3 almost doubled specificity in detecting risk drinking whereas maintaining adequate sensitivity, equivalent to that in the original report, and identified substantially more neurobehavioral deficits in children. Redefining tolerance at three drinks did not improve T-ACE effectiveness in predicting outcomes. This study is among the first to show the ability of an in-pregnancy T-ACE assessment to predict child neurodevelopmental outcome. In addition, increasing the total T-ACE score criterion (from 2 to 3) improved identification of non-drinking mothers and unaffected children with little loss in detection of drinkers and affected children. Efficient in-pregnancy screens for risk drinking afford greater opportunities for intervention that could prevent/limit FASDs.