Linoleic acid is associated with lower long-chain n-6 and n-3 fatty acids in red blood cell lipids of Canadian pregnant women

Lipid organization and turnover in the plasma membrane of human differentiating neural progenitor cells revealed by time-of-flight secondary ion mass spectrometry imaging

Membrane lipids have been known to influence multiple signalling and cellular processes. Dysregulation of lipids at the neuronal membrane is connected to a significant alteration of the brain function and morphology, leading to brain diseases and neurodegeneration. Understanding the lipid composition and turnover of neuronal membrane will provide a significant insight into the molecular events underlying the regulatory effects of these biomolecules in a neuronal system. In this study, we aimed to characterize the composition and turnover of the plasma membrane lipids in human neural progenitor cells (NPCs) at an early differentiation stage into midbrain neurons using ToF-SIMS imaging. Lipid composition of the native plasma membrane was explored, followed by an examination of the lipid turnover using different isotopically labelled lipid precursors, including 13C-choline, 13C-lauric acid, 15N-linoleic, and 13C-stearic. Our results showed that differentiating NPCs contain a high abundance of ceramides, glycerophosphoserines, neutral glycosphingolipids, diradylglycerols, and glycerophosphocholines at the plasma membrane. In addition, different precursors were found to incorporate into different membrane lipids which are specific for the short- or long-carbon chains, and the unsaturation or saturation stage of the precursors. The lipid structure of neuronal membrane reflects the differentiation status of NPCs, and it can be altered significantly using a particular lipid precursor. Our study illustrates a potential of ToF-SIMS imaging to study native plasma membrane lipids and elucidate complex cellular processes by providing molecular -rich information at a single cell level.

Dietary habits and plasma lipid concentrations in a general Japanese population

INTRODUCTION

Accumulating data on the associations between food consumption and lipid composition in the body is essential for understanding the effects of dietary habits on health.

OBJECTIVES

As part of omics research in the Tohoku Medical Megabank Community-Based Cohort Study, this study sought to reveal the dietary impact on plasma lipid concentration in a Japanese population.

METHODS

We conducted a correlation analysis of food consumption and plasma lipid concentrations measured using mass spectrometry, for 4032 participants in Miyagi Prefecture, Japan.

RESULTS

Our analysis revealed 83 marked correlations between six food categories and the concentrations of plasma lipids in nine subclasses. Previously reported associations, including those between seafood consumption and omega-3 fatty acids, were validated, while those between dairy product consumption and odd-carbon-number fatty acids (odd-FAs) were validated for the first time in an Asian population. Further analysis suggested that dairy product consumption is associated with odd-FAs via sphingomyelin (SM), which suggests that SM is a carrier of odd-FAs. These results are important for understanding odd-FA metabolism with regards to dairy product consumption.

CONCLUSION

This study provides insight into the dietary impact on plasma lipid concentration in a Japanese population.

Dietary linoleic acid lowering alone does not lower arachidonic acid or endocannabinoids among women with overweight and obesity: A randomized, controlled trial

The linoleic acid (LA)-arachidonic acid (ARA)-inflammatory axis suggests dietary LA lowering benefits health because it lowers ARA and ARA-derived endocannabinoids (ECB). Dietary LA reduction increases concentrations of omega-3 eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and DHA derived ECB. The aim of this study was to examine targeted reduction of dietary LA, with and without EPA and DHA, on plasma EPA and DHA and ECB (2-arachidonoyl glycerol [2-AG], anandamide [AEA], and docosahexaenoyl ethanolamide [DHA-EA]). Healthy, pre-menopausal women (n = 62, BMI 30 ± 3 kg/m2 , age 35 ± 7 years; mean ± SD) were randomized to three 12-week controlled diets: (1) high LA, low omega-3 EPA and DHA (H6L3); (2) low LA, low omega-3 EPA and DHA (L6L3); or (3) low LA, high omega-3 EPA and DHA (L6H3). Baseline plasma fatty acids and ECB were similar between diets. Starting at 4 weeks, L6L3 and L6H3 lowered plasma LA compared to H6L3 (p < 0.001). While plasma ARA changed from baseline by 8% in L6L3 and -8% in L6H3, there were no group differences. After 4 weeks, plasma EPA and DHA increased from baseline in women on the L6H3 diet (ps < 0.001) and were different than the H6L3 and L6L3 diets. No differences were found between diets for AEA or 2-AG, however, in L6L3 and L6H3, AEA increased by 14% (ps < 0.02). L6H3 resulted in 35% higher DHA-EA (p = 0.013) whereas no changes were seen with the other diets. Lowering dietary LA did not result in the expected changes in fatty acids associated with the LA-ARA inflammatory axis in women with overweight and obesity.

Fatty acid composition and genome-wide associations of a chickpea (Cicer arietinum L.) diversity panel for biofortification efforts

Chickpea is a nutritionally dense pulse crop with high levels of protein, carbohydrates, micronutrients and low levels of fats. Chickpea fatty acids are associated with a reduced risk of obesity, blood cholesterol, and cardiovascular diseases in humans. We measured four primary chickpea fatty acids; palmitic acid (PA), linoleic acid (LA), alpha-linolenic acid (ALA), and oleic acid (OA), which are crucial for human health and plant stress responses in a chickpea diversity panel with 256 accessions (Kabuli and desi types). A wide concentration range was found for PA (450.7-912.6 mg/100 g), LA (1605.7-3459.9 mg/100 g), ALA (416.4-864.5 mg/100 g), and OA (1035.5-1907.2 mg/100 g). The percent recommended daily allowances also varied for PA (3.3-6.8%), LA (21.4-46.1%), ALA (34.7-72%), and OA (4.3-7.9%). Weak correlations were found among fatty acids. Genome-wide association studies (GWAS) were conducted using genotyping-by-sequencing data. Five significant single nucleotide polymorphisms (SNPs) were identified for PA. Admixture population structure analysis revealed seven subpopulations based on ancestral diversity in this panel. This is the first reported study to characterize fatty acid profiles across a chickpea diversity panel and perform GWAS to detect associations between genetic markers and concentrations of selected fatty acids. These findings demonstrate biofortification of chickpea fatty acids is possible using conventional and genomic breeding techniques, to develop superior cultivars with better fatty acid profiles for improved human health and plant stress responses.

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.

Dietary Intake Patterns and Lifestyle Behaviors of Pregnant Women Living in a Manitoba First Nations Community: Implications for Fetal Alcohol Spectrum Disorder

The information on the nutrition status of women at-risk of carrying a child with fetal alcohol spectrum disorder (FASD) is scarce, particularly in the First Nations population living on reserve. This study examined and compared nutrition status, dietary intake, and lifestyle patterns of pregnant at-risk, defined as those who consume alcoholic drink during the current pregnancy, and non-at-risk women living in northern Manitoban community. Thirty-seven pregnant, First Nations women (at-risk n = 15; non-at-risk, n = 22) were recruited to participate in the study. A questionnaire, presented in paper and iPad formats, collected information on participants’ demographics, dietary intake, lifestyle, pregnancy outcomes, and maternal health. A food frequency questionnaire and 24-h recall were used to determine nutrient intake. Nutrient values were assessed using Dietary Reference Intakes (DRI). At-risk and non-at-risk women were below the Canada Food Guide serving size recommended for Vegetable and Fruit, Grain, and Milk Products with 93%, 92%, and 93% of participants not meeting the recommendations, respectively. Women met the recommendations for vitamins A, B1, B12, C, niacin, choline, as well as calcium, and zinc. Sixty eight percentage (%) of participants did not meet the recommendations for folate and iron, and 97% for docosahexaenoic acid (DHA). Significant differences were observed between non-at-risk and at-risk women for mean % DRI intakes of vitamin C (313 ± 224 vs. 172 ± 81 mg/day), niacin (281 ± 123 vs. 198 ± 80 mg/day), folate (70 ± 38 vs. 10 ± 22 mcg/day), and iron (101 ± 74 vs. 74 ± 30 mg/day). The findings of this study lay a fundamental premise for the development of community nutrition programs, nutrition education, and nutrition intervention, such as community specific prenatal supplementation. These will assist in ensuring adequate maternal nutrient intake and benefit families and communities in Northern Manitoba with and without alcohol insult.

Complexity of understanding the role of dietary and erythrocyte docosahexaenoic acid (DHA) on the cognitive performance of school-age children

Background

Early childhood is a period of rapid brain development, with increases in synapses rich in the omega-3 (ω-3) fatty acid, DHA (22:6ω-3) continuing well beyond infancy. Despite the importance of DHA to neural phospholipids, the requirement of dietary DHA for neurodevelopment remains unclear.

Objectives

The aim was to assess the dietary DHA and DHA status of young children, and determine the association with cognitive performance.

Methods

This was a cross-sectional study of healthy children (5-6 y), some of whom were enrolled in a follow-up of a clinical trial (NCT00620672). Dietary intake data (n = 285) were assessed with a food-frequency questionnaire (FFQ) and three 24-h recalls. Family characteristics were collected by questionnaire, and anthropometric data measured. Venous blood was collected, cognitive performance assessed using several age-appropriate tools including the Kaufman Assessment Battery for Children. The relation between dietary DHA, RBC DHA, and child neurodevelopment test scores was determined using Pearson's correlation or Spearman's rho, and quintiles of test scores compared by Mann-Whitney U test.

Results

Child DHA intakes were highly variable, with a stronger association between RBC DHA and DHA intake assessed by FFQ (rho = 0.383, P < 0.001) compared with one or three 24-h recalls. Observed ethnic differences in DHA intake status as well as neurodevelopmental test scores led to analysis of the association between DHA intake and status with neurodevelopment test scores for White children only (n = 190). Child RBC DHA status was associated with neurodevelopment test scores, including language (rho = 0.211, P = 0.009) and short-term memory (rho = 0.187, P = 0.019), but only short-term memory was associated with dietary DHA (rho = 0.221, P = 0.003).

Conclusions

Child RBC DHA but not dietary DHA was associated with multiple tests of cognitive performance. In addition, DHA intake was only moderately associated with RBC DHA, raising complex questions on the relation between diet, DHA transfer to membrane lipids, and neural function.

Fatty acid compositions of immature and mature testis are differently responsive to dietary docosahexasenoic acid during development in rats exposed to prenatal ethanol

BACKGROUND

Ethanol (EtOH) exposure impairs, but docosahexaenoic acid (DHA) supports testis functions. This study investigated whether dietary DHA and prenatal EtOH exposure affected fatty acid profiles equally in immature and mature testis during developmental stages.

METHODS

Female rats were exposed to ± EtOH (3g/kg BW, twice a day via gavage) throughout pregnancy, while consuming a diet supplemented ± DHA (1.4%, w/w). Pups were continued on their mother's diet after weaning with testes collected for fatty acid analysis at different stages of reproductive development, at gestational day 20 (GD20) and postnatal day (PD) 4, 21, 49, and 90, to present fetal, neonatal, weaning, prepubertal and adult stages, respectively.

RESULTS

Regardless of EtOH exposure, dietary DHA significantly increased in testis DHA at all ages, with testis at weaning and prepuberty being more responsive to the diet (p<0.0002). Immature testis at GD20 and PD4 contained more DHA than n-6 docosapentaenoic acid (n-6 DPA) compared to mature testis while being well responsive to the maternal DHA diet through gestation and lactation. The level of n-6 very long chain fatty acids and (VLCFA) and n-6 DPA, distinctively increased from weaning and prepuberty, respectively, and were not reduced by the DHA diet at prepuberty and adulthood. Prenatal EtOH minimally affected testis fatty acids during development.

CONCLUSION

Immature and mature testis responds differently to dietary DHA. The age around sexual maturity might be a critical time for dietary intervention as testis was more responsive to diet at this time point. The increase in DPA and n-6 VLCFA in matured testis while not affected by dietary DHA, indicates their critical roles in male reproductive function in rodents.

Changes in fatty acid levels (saturated, monounsaturated and polyunsaturated) during pregnancy

BACKGROUND

During pregnancy a high amount of fatty acids (FA) is necessary to meet foetus demands, which vary during gestation. The present study describes the changes in maternal fatty acid concentrations during pregnancy in a sample of pregnant women.

METHODS

This is a longitudinal study of 479 pregnant women who were monitored from the first trimester to third trimester of pregnancy. Data on maternal characteristics were recorded and a serum sample was collected in each trimester. The fatty acid profile (saturated (SFA: total, lauric acid, myristic acid, palmitic acid, stearic acid), monounsaturated (MUFA: total, palmitoleic acid, oleic acid) and polyunsaturated fatty acids (PUFA: total omega-6 (n-6), linoleic acid, dihomo-γ-linolenic acid, arachidonic acid (AA), total omega-3 (n-3), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA)) was analysed with a gas chromatography-mass spectrometry combination.

RESULTS

From the first trimester to third trimester of pregnancy, a significant increase in total SFA, total MUFA and total n-6 PUFA was found. (p < 0.001). Nevertheless, the serum concentration of arachidonic acid (AA), eicosapentaenoic acid (EPA) and total n-3 PUFA decreased during gestation (p < 0.001). A statistically non-significant result was observed for the docosahexaenoic acid (DHA) serum concentration between the first and third trimesters of pregnancy. Significant correlations were observed between each total fatty acid concentrations of the first and third trimesters.

CONCLUSION

The circulating serum concentration of SFA, MUFA and n-6 PUFA increases during pregnancy, whereas essential fatty acids such as AA and EPA decrease, and DHA remains unchanged. Further research is necessary to understand the role played by FA throughout gestation.

Type 2 diabetes preventive effects with a 12-months sardine-enriched diet in elderly population with prediabetes: An interventional, randomized and controlled trial

BACKGROUND

Fish could play a role in preventing type 2 diabetes (T2D) but there has been little specification about the type of fish and the preventive mechanism involved in its health claim. The sardine is a source of omega-3 and taurine that, in isolation or in synergy, would produce T2D-delaying through different molecular mechanism.

HYPOTHESIS

The consumption of twice a week of sardine, during one year would reduce T2D-developing risk in a population with prediabetes (preDM) and old age.

DESIGN

152 subjects with fasting glucose between 100-124 mg/dL aged ≥65 yo were recruited from three primary care centers in Barcelona and were randomly distributed among two interventional groups: control group (CG) and sardine group (SG). Both groups received same T2D-prevention nutritional during a year but only SG had to add 200 g of sardine per week. All variables were collected before to start and at the end of the diet. (ClinicalTrials.gov: NCT03557541).

RESULTS

152 people were randomized into CG (n=77) and SG (n=75) with 18 and 12 drop outs respectively. Subjects in SG, significantly compared to CG, decreased percentage classified-individuals in a very high risk group to develop T2D according to FINDRISC (p=0.035). In addition to increasing HDL-cholesterol and adiponectin and decreasing triglycerides (p<0.05) and blood pressure (<0.05), SG showed a lower HOMA-IR (p=0.032). The consumption of sardine characteristics nutrients as omega-3, EPA and DHA, vitamin D, fluorine and taurine were higher for SG (p<0.05). These results agreed with the increased of taurine, fatty acid (FA) omega-3 and bile acids circulating metabolites (p<0.05). Changes erythrocyte membrane FA were detected only in SG with a decrease of 5 omega-6 FA (p<0.001) and an increase of 3 omega-3 FA types (p<0.001).

CONCLUSION

We conclude that a year T2D-prevention diet with sardine supplementation has a greater protective effect against developing T2D and CV events.

Is the ENaC Dysregulation in CF an Effect of Protein-Lipid Interaction in the Membranes?

While approximately 2000 mutations have been discovered in the gene coding for the cystic fibrosis transmembrane conductance regulator (CFTR), only a small amount (about 10%) is associated with clinical cystic fibrosis (CF) disease. The discovery of the association between CFTR and the hyperactive epithelial sodium channel (ENaC) has raised the question of the influence of ENaC on the clinical CF phenotype. ENaC disturbance contributes to the pathological secretion, and overexpression of one ENaC subunit, the β-unit, can give a CF-like phenotype in mice with normal acting CFTR. The development of ENaC channel modulators is now in progress. Both CFTR and ENaC are located in the cell membrane and are influenced by its lipid configuration. Recent studies have emphasized the importance of the interaction of lipids and these proteins in the membranes. Linoleic acid deficiency is the most prevailing lipid abnormality in CF, and linoleic acid is an important constituent of membranes. The influence on sodium excretion by linoleic acid supplementation indicates that lipid-protein interaction is of importance for the clinical pathophysiology in CF. Further studies of this association can imply a simple clinical adjuvant in CF therapy.

Long-Chain Polyunsaturated Fatty Acids, Homocysteine at Birth and Fatty Acid Desaturase Gene Cluster Polymorphisms are Associated with Children's Processing Speed up to Age 9 Years

Both pre- and early postnatal supplementation with docosahexaenoic acid (DHA), arachidonic acid (AA) and folate have been related to neural development, but their long-term effects on later neural function remain unclear. We evaluated the long-term effects of maternal prenatal supplementation with fish-oil (FO), 5-methyltetrahydrofolate (5-MTHF), placebo or FO + 5-MTHF, as well as the role of fatty acid desaturase (FADS) gene cluster polymorphisms, on their offspring’s processing speed at later school age. This study was conducted in NUHEAL children at 7.5 (n = 143) and 9 years of age (n = 127). Processing speed tasks were assessed using Symbol Digit Modalities Test (SDMT), Children Color Trails Test (CCTT) and Stroop Color and Word Test (SCWT). Long-chain polyunsaturated fatty acids, folate and total homocysteine (tHcy) levels were determined at delivery from maternal and cord blood samples. FADS and methylenetetrahydrofolate reductase (MTHFR) 677 C > T genetic polymorphisms were analyzed. Mixed models (linear and logistic) were performed. There were significant differences in processing speed performance among children at different ages (p < 0.001). The type of prenatal supplementation had no effect on processing speed in children up to 9 years. Secondary exploratory analyses indicated that children born to mothers with higher AA/DHA ratio at delivery (p < 0.001) and heterozygotes for FADS1 rs174556 (p < 0.05) showed better performance in processing speed at 9 years. Negative associations between processing speed scores and maternal tHcy levels at delivery were found. Our findings suggest speed processing development in children up to 9 years could be related to maternal factors, including AA/DHA and tHcy levels, and their genetic background, mainly FADS polymorphism. These considerations support that maternal prenatal supplementation should be quantitatively adequate and individualized to obtain better brain development and mental performance in the offspring.

A pilot study on the effect of early provision of dietary docosahexaenoic acid on testis development, functions, and sperm quality in rats exposed to prenatal ethanol

BACKGROUND

Prenatal ethanol (EtOH) exposure is associated with adverse effect on the male reproductive function. Dietary docosahexaenoic acid (DHA) is known to improve testis function and sperm parameters, thereby male fertility. This study piloted whether dietary DHA influences testis development and function in rats exposed to prenatal EtOH.

METHODS

Pregnant female Sprague-Dawley rats (n = 30) received either EtOH (3 g/kg, twice a day, n = 14) or dextrose (n = 16) throughout pregnancy. Moreover, they were fed either diet supplemented with (Cont + DHA, n = 8, EtOH + DHA, n = 6) or without DHA (1.4% w/w of total fatty acids) (Cont, EtOH, n = 8 each), with pups being continued on their mothers' diet after weaning. Tissues were collected at gestational day (GD) 20, postnatal day (PD) 4, 21, 49 and 90 for analyzing testicular developmental markers and sperm parameters, and plasma for testosterone.

RESULTS

Dietary DHA increased serum testosterone at GD20 (p < .05) and sperm normal morphology at PD90 (p < .0001) compared to the group without DHA supplementation. Dietary DHA also increased the height of germinal epithelium at peripuberty, PD49 (p < .03). The EtOH exposure induced a marked decline in the testicular gene expression of StAR at PD49 (p < .02) than those of non-EtOH treated group.

CONCLUSIONS

These findings indicate that dietary DHA may positively contribute to male fertility by impacting sperm normal morphology likely by increasing fetal testosterone level. Prenatal EtOH exposure did not adversely affect the overall testis developmental markers during development and sperm parameters in adulthood.

DHA supplementation during prenatal ethanol exposure alters the expression of fetal rat liver genes involved in oxidative stress regulation

Prenatal ethanol (EtOH) exposure is known to induce adverse effects on fetal brain development. Docosahexaenoic acid (DHA) has been shown to alleviate these effects by up-regulating antioxidant mechanisms in the brain. The liver is the first organ to receive enriched blood after placental transport. Therefore, it could be negatively affected by EtOH, but no studies have assessed the effects of DHA on fetal liver. This study examined the effects of maternal DHA intake on DHA status and gene expression of key enzymes of the glutathione antioxidant system in the fetal liver after prenatal EtOH exposure. Pregnant Sprague-Dawley dams were intubated with EtOH for the first 10 days of pregnancy, while being fed a control or DHA-supplemented diet. Fetal livers were collected at gestational day 20, and free fatty acids and phospholipid profile, as well as glutathione reductase (GR) and glutathione peroxidase-1 (GPx1) gene expressions, were assessed. Prenatal EtOH exposure increased fetal liver weight, whereas maternal DHA supplementation decreased fetal liver weight. DHA supplementation increased fetal liver free fatty acid and phospholipid DHA independently of EtOH. GR and GPx1 messenger RNA (mRNA) expressions were significantly increased and decreased, respectively, in the EtOH-exposed group compared with all other groups. Providing DHA normalized GR and GPx1 mRNA expression to control levels. This study shows that maternal DHA supplementation alters the expression of fetal liver genes involved in the glutathione antioxidative system during prenatal EtOH exposure. The fetal liver may play an important role in mitigating the signs and symptoms of fetal alcohol spectrum disorders in affected offspring.

Omega-3 fatty acid addition during pregnancy

BACKGROUND

Higher intakes of foods containing omega-3 long-chain polyunsaturated fatty acids (LCPUFA), such as fish, during pregnancy have been associated with longer gestations and improved perinatal outcomes. This is an update of a review that was first published in 2006.

OBJECTIVES

To assess the effects of omega-3 LCPUFA, as supplements or as dietary additions, during pregnancy on maternal, perinatal, and neonatal outcomes and longer-term outcomes for mother and child.

SEARCH METHODS

For this update, we searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (16 August 2018), and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing omega-3 fatty acids (as supplements or as foods, stand-alone interventions, or with a co-intervention) during pregnancy with placebo or no omega-3, and studies or study arms directly comparing omega-3 LCPUFA doses or types. Trials published in abstract form were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility, extracted data, assessed risk of bias in trials and assessed quality of evidence for prespecified birth/infant, maternal, child/adult and health service outcomes using the GRADE approach.

MAIN RESULTS

In this update, we included 70 RCTs (involving 19,927 women at low, mixed or high risk of poor pregnancy outcomes) which compared omega-3 LCPUFA interventions (supplements and food) compared with placebo or no omega-3. Overall study-level risk of bias was mixed, with selection and performance bias mostly at low risk, but there was high risk of attrition bias in some trials. Most trials were conducted in upper-middle or high-income countries; and nearly half the trials included women at increased/high risk for factors which might increase the risk of adverse maternal and birth outcomes.Preterm birth < 37 weeks (13.4% versus 11.9%; risk ratio (RR) 0.89, 95% confidence interval (CI) 0.81 to 0.97; 26 RCTs, 10,304 participants; high-quality evidence) and early preterm birth < 34 weeks (4.6% versus 2.7%; RR 0.58, 95% CI 0.44 to 0.77; 9 RCTs, 5204 participants; high-quality evidence) were both lower in women who received omega-3 LCPUFA compared with no omega-3. Prolonged gestation > 42 weeks was probably increased from 1.6% to 2.6% in women who received omega-3 LCPUFA compared with no omega-3 (RR 1.61 95% CI 1.11 to 2.33; 5141 participants; 6 RCTs; moderate-quality evidence).For infants, there was a possibly reduced risk of perinatal death (RR 0.75, 95% CI 0.54 to 1.03; 10 RCTs, 7416 participants; moderate-quality evidence: 62/3715 versus 83/3701 infants) and possibly fewer neonatal care admissions (RR 0.92, 95% CI 0.83 to 1.03; 9 RCTs, 6920 participants; moderate-quality evidence - 483/3475 infants versus 519/3445 infants). There was a reduced risk of low birthweight (LBW) babies (15.6% versus 14%; RR 0.90, 95% CI 0.82 to 0.99; 15 trials, 8449 participants; high-quality evidence); but a possible small increase in large-for-gestational age (LGA) babies (RR 1.15, 95% CI 0.97 to 1.36; 6 RCTs, 3722 participants; moderate-quality evidence, for omega-3 LCPUFA compared with no omega-3. Little or no difference in small-for-gestational age or intrauterine growth restriction (RR 1.01, 95% CI 0.90 to 1.13; 8 RCTs, 6907 participants; moderate-quality evidence) was seen.For the maternal outcomes, there is insufficient evidence to determine the effects of omega-3 on induction post-term (average RR 0.82, 95% CI 0.22 to 2.98; 3 trials, 2900 participants; low-quality evidence), maternal serious adverse events (RR 1.04, 95% CI 0.40 to 2.72; 2 trials, 2690 participants; low-quality evidence), maternal admission to intensive care (RR 0.56, 95% CI 0.12 to 2.63; 2 trials, 2458 participants; low-quality evidence), or postnatal depression (average RR 0.99, 95% CI 0.56 to 1.77; 2 trials, 2431 participants; low-quality evidence). Mean gestational length was greater in women who received omega-3 LCPUFA (mean difference (MD) 1.67 days, 95% CI 0.95 to 2.39; 41 trials, 12,517 participants; moderate-quality evidence), and pre-eclampsia may possibly be reduced with omega-3 LCPUFA (RR 0.84, 95% CI 0.69 to 1.01; 20 trials, 8306 participants; low-quality evidence).For the child/adult outcomes, very few differences between antenatal omega-3 LCPUFA supplementation and no omega-3 were observed in cognition, IQ, vision, other neurodevelopment and growth outcomes, language and behaviour (mostly low-quality to very low-quality evidence). The effect of omega-3 LCPUFA on body mass index at 19 years (MD 0, 95% CI -0.83 to 0.83; 1 trial, 243 participants; very low-quality evidence) was uncertain. No data were reported for development of diabetes in the children of study participants.

AUTHORS' CONCLUSIONS

In the overall analysis, preterm birth < 37 weeks and early preterm birth < 34 weeks were reduced in women receiving omega-3 LCPUFA compared with no omega-3. There was a possibly reduced risk of perinatal death and of neonatal care admission, a reduced risk of LBW babies; and possibly a small increased risk of LGA babies with omega-3 LCPUFA.For our GRADE quality assessments, we assessed most of the important perinatal outcomes as high-quality (e.g. preterm birth) or moderate-quality evidence (e.g. perinatal death). For the other outcome domains (maternal, child/adult and health service outcomes) GRADE ratings ranged from moderate to very low, with over half rated as low. Reasons for downgrading across the domain were mostly due to design limitations and imprecision.Omega-3 LCPUFA supplementation during pregnancy is an effective strategy for reducing the incidence of preterm birth, although it probably increases the incidence of post-term pregnancies. More studies comparing omega-3 LCPUFA and placebo (to establish causality in relation to preterm birth) are not needed at this stage. A further 23 ongoing trials are still to report on over 5000 women, so no more RCTs are needed that compare omega-3 LCPUFA against placebo or no intervention. However, further follow-up of completed trials is needed to assess longer-term outcomes for mother and child, to improve understanding of metabolic, growth and neurodevelopment pathways in particular, and to establish if, and how, outcomes vary by different types of omega-3 LCPUFA, timing and doses; or by characteristics of women.

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.

RRR-α-Tocopherol Is the Predominant Stereoisomer of α-Tocopherol in Human Milk

BACKGROUND

The naturally occurring α-tocopherol (α-T) stereoisomer, RRR-α-tocopherol (RRR-α-T), is known to be more bioactive than all-rac-α-tocopherol (all-rac-α-T), a synthetic racemic mixture of 8 stereoisomers. There is widespread use of all-rac-α-T in maternal supplements.

OBJECTIVE

The aim of the study was to thoroughly describe the α-T stereoisomer profile of human milk.

METHODS

We measured the α-T stereoisomer profile in milk from 2 cohorts of women: a cohort of 121 women who provided milk on days 30 and 60 of lactation (study 1) and a separate cohort of 51 women who provided milk on days 10, 21, 71, and 120 of lactation (study 2).

RESULTS

RRR-α-T was the predominant stereoisomer (P < 0.0001) in all samples in both studies despite a large intrasubject range in total α-T (0.7-22 μg/mL). On average, RRR-α-T comprised 73-76% of total α-T, but average values for the synthetic stereoisomers were RRS, 8-14%; RSR, 6-8%; RSS, 5-6%; and the sum of 2S stereoisomers (Σ2S), 3-5%. Despite the predominance of RRR-α-T, the sum of the synthetic stereoisomers comprised as much as 48% of total α-T. We calculated the ratio of RRR to the sum of the synthetic 2R (RRS + RSR + RSS) stereoisomers (s2R) to assess the degree to which RRR is favored in milk. Consistent with discrimination among 2R stereoisomers in mammary tissue, RRR/s2R values ranged from 2.8 to 3.6, as opposed to the expected ratio of 0.33 if there was no discrimination. However, the RRR to s2R ratio did not correlate with milk α-T concentration, but both components of the ratio did.

CONCLUSIONS

RRR-α-T is the predominant stereoisomer in human milk, concentrations of synthetic 2R stereoisomers were notable, and the relation between milk total α-T and stereoisomer profile is complex. Due to the wide range found in milk α-T stereoisomer profile, investigation into its impact on α-T status and functional outcomes in breastfed infants is warranted.

Dietary Intake of DHA and EPA in a Group of Pregnant Women in the Moncton Area

Purpose: To compare docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and fish intake of pregnant women at 30 weeks of gestation to current recommendations and to determine the factors associated with omega-3 (ω-3) intake.

Methods: A food frequency questionnaire was completed by 54 women (54/131 = 41%) at 30 ± 0.8 weeks gestation. Supplement intake, sociodemographic characteristics, and ω-3 food habits were evaluated.

Results: Among this high socioeconomic status (SES) group, 66.7% and 64.8% met the Food and Agriculture Organization of the United Nations (FAO)/World Health Organization (WHO) recommendation of 200 mg/d DHA and 300 mg/d DHA + EPA, respectively, and only 48.1% met the Academy of Nutrition and Dietetics (Academy) recommendation of 500 mg/d DHA + EPA. Eighteen of the 54 women took a ω-3 supplement during the third trimester. This significantly improved their total intake to meet the FAO/WHO (88.9% ≥200 mg/d DHA and 94.4% ≥300 mg/d DHA + EPA) and the Academy (77.8% ≥500 mg/d DHA + EPA) recommendations. Among nonsupplement users (36/54), 50% met the FAO/WHO recommendations and only 33.3% met the Academy recommendations.

Conclusions: Results suggest that the majority of high SES women did not meet ω-3 recommendations from food alone. Continued prenatal education on the importance of fish intake and on the addition of ω-3 prenatal supplement is essential.

Improvement of the omega 3 index of healthy subjects does not alter the effects of dietary saturated fats or n-6PUFA on LDL profiles

BACKGROUND AND AIMS

Dietary fat composition is known to modulate circulating lipid and lipoprotein levels. Although supplementation with long chain omega-3 polyunsaturated fatty acids (LCn-3PUFA) has been shown to reduce plasma triglyceride levels, the effect of the interactions between LCn-3PUFA and the major dietary fats consumed has not been previously investigated.

METHODS

In a randomized controlled parallel design clinical intervention, we examined the effect of diets rich in either saturated fatty acids (SFA) or omega-6 polyunsaturated fatty acids (n-6PUFA) on plasma lipid levels and lipoprotein profiles (lipoprotein size, concentration and distribution in subclasses) in subjects with an adequate omega 3 index. Twenty six healthy subjects went through a four-week pre-supplementation period with LCn-3PUFA and were then randomized to diets rich in either n-6PUFA or SFA both supplemented with LCn-3PUFA.

RESULTS

The diet rich in n-6PUFA decreased low density lipoprotein (LDL) particle concentration (-8%, p=0.013) and LDL cholesterol (LDL-C) level (-8%, p=0.021), while the saturated fat rich diet did not affect LDL particle concentration or LDL-C levels significantly. Nevertheless, dietary saturated fatty acids increased LCn-3PUFA in plasma and tissue lipids compared with n-6PUFA, potentially reducing other cardiovascular risk factors such as inflammation and clotting tendency.

CONCLUSION

Improvement on the omega 3 index of healthy subjects did not alter the known effects of dietary saturated fats and n-6PUFA on LDL profiles.

Prepartum maternal diets supplemented with oilseeds alter the fatty acid profile in bovine neonatal plasma possibly through reduced placental expression of fatty acid transporter protein 4 and fatty acid translocase

In the present study, we determined the effects of maternal dietary fat and the type of fat on plasma fatty acids and the expression of placental fatty acid transporter genes. In Experiment 1, Holstein cows in the last 35 days of gestation received diets containing sunflower seed (n = 8; high in linoleic acid (LA)), canola seed (n = 7; high in oleic acid (OLA)) or no oilseed (n = 7; control). Fatty acids were quantified in dam and neonate plasma at calving. In Experiment 2, placental cotyledons were collected (LA: n = 4; OLA: n = 4; control: n = 5) to quantify gene expression. Maternal long-chain polyunsaturated fatty acids, neonatal total n-3 fatty acids and eicosapentaenoic acid (EPA) declined, whereas docosahexaenoic acid (DHA) and total fat tended to decline following fat supplementation prepartum. Feeding of LA versus OLA prepartum tended to increase peroxisome proliferator-activated receptor α (PPARA) expression, whereas peroxisome proliferator-activated receptor δ (PPARD) and peroxisome proliferator-activated receptor γ (PPARG) expression tended to be higher in OLA- than LA-fed cows. Expression of fatty acid transporter protein 4 (FATP4) and fatty acid translocase (FAT/CD36) expression was lower in placental tissue of cows fed fat compared with control cows. Reduced total n-3 fatty acids, EPA and DHA in neonates born of dams fed fat prepartum is likely due to changes in PPARs and reduced expression of placental FATP4 and FAT/CD36.

Characterization of the FAD2 Gene Family in Soybean Reveals the Limitations of Gel-Based TILLING in Genes with High Copy Number

Soybean seed oil typically contains 18-20% oleic acid. Increasing the content of oleic acid is beneficial for health and biodiesel production. Mutations in FAD2-1 genes have been reported to increase seed oleic acid content. A subset of 1,037 mutant families from a mutagenized soybean cultivar (cv.) Forrest population was screened using reverse genetics (TILLING) to identify mutations within FAD2 genes. Although no fad2 mutants were identified using gel-based TILLING, four fad2-1A and one fad2-1B mutants were identified to have high seed oleic acid content using forward genetic screening and subsequent target sequencing. TILLING has been successfully used as a non-transgenic reverse genetic approach to identify mutations in genes controlling important agronomic traits. However, this technique presents limitations in traits such as oil composition due to gene copy number and similarities within the soybean genome. In soybean, FAD2 are present as two copies, FAD2-1 and FAD2-2. Two FAD2-1 members: FAD2-1A and FAD2-1B; and three FAD2-2 members: FAD2-2A, FAD2-2B, and FAD2-2C have been reported. Syntenic, phylogenetic, and in silico analysis revealed two additional members constituting the FAD2 gene family: GmFAD2-2D and GmFAD2-2E, located on chromosomes 09 and 15, respectively. They are presumed to have diverged from other FAD2-2 members localized on chromosomes 19 (GmFAD2-2A and GmFAD2-2B) and 03 (GmFAD2-2C). This work discusses alternative solutions to the limitations of gel-based TILLING in functional genomics due to high copy number and multiple paralogs of the FAD2 gene family in soybean.

Human Milk Plasmalogens Are Highly Enriched in Long-Chain PUFAs

BACKGROUND

Human milk contains unique glycerophospholipids, including ethanolamine-containing plasmalogens (Pls-PEs) in the milk fat globule membrane, which have been implicated in infant brain development. Brain Pls-PEs accumulate postnatally and are enriched in long-chain polyunsaturated fatty acids (LC-PUFAs), particularly docosahexaenoic acid (DHA). Fatty acid (FA) composition of Pls-PEs in milk is poorly understood because of the analytical challenges in separating Pls-PEs from other phospholipids in the predominating presence of triacylglycerols. The variability of Pls-PE FAs and the potential role of maternal diet remain unknown.

OBJECTIVES

Our primary objectives were to establish improved methodology for extracting Pls-PEs from human milk, enabling FA analysis, and to compare FA composition between Pls-PEs and 2 major milk phospholipids, phosphatidylcholine and phosphatidylethanolamine. Our secondary objective was to explore associations between maternal DHA intake and DHA in milk phospholipids and variability in phospholipid-DHA within a woman.

METHODS

Mature milk was collected from 25 women, with 4 providing 3 milk samples on 3 separate days. Lipids were extracted, and phospholipids were removed by solid phase extraction. Pls-PEs were separated by using normal-phase HPLC, recovered and analyzed for FAs by GLC. Diet was assessed by using a validated food-frequency questionnaire.

RESULTS

Pls-PE concentration in human milk was significantly higher in LC-PUFAs than phosphatidylethanolamine and phosphatidylcholine, including arachidonic acid (AA) and DHA. The mean ± SD concentration of AAs in Pls-PEs was ∼2.5-fold higher than in phosphatidylethanolamine (10.5 ± 1.71 and 3.82 ± 0.92 g/100 g, respectively). DHA in Pls-PEs varied across women (0.95-6.51 g/100 g), likely independent of maternal DHA intake. Pls-PE DHA also varied within a woman across days (CV ranged from 9.8% to 28%).

CONCLUSIONS

Human milk provides the infant with LC-PUFAs from multiple lipid pools, including a source from Pls-PEs. The biological determinants of Pls-PE FAs and physiological relevance to the breastfed infant remain to be elucidated.

Kinetics of omega-3 polyunsaturated fatty acids when co-administered with saturated or omega-6 fats

OBJECTIVE

Absorption of long chain omega-3 polyunsaturated fatty acids (LCn-3PUFA) has been shown to be potentiated when consumed with a high fat meal. However, the effect of different dietary fats on n-3PUFA absorption and postprandial kinetics has not been previously studied.

METHOD

In a randomized cross-over design intervention, postprandial incorporation of LCn-3PUFA into plasma lipids following consumption of a meal rich in either saturated fat or omega-6 polyunsaturated fatty acids (n-6PUFA) was investigated. Healthy adult male and female subjects (n=26) were fed an isocaloric meal containing equivalent amount of either butter or sunflower seed oil supplemented with 1.8grams of LCn-3PUFA (300mg eicosapentaenoic acid, 20:5n-3 and 1500mg docosahexaenoic acid, 22:6n-3).

RESULTS

Postprandial plasma lipids were enriched with saturated fatty acids and linoleic acid (18:2n-6) following consumption of the butter and the sunflower oil containing meals respectively. The increase in plasma 20:5n-3 and 22:6n-3 levels over the 6hour study period was similar in both the saturated and the n-6 fat groups.

CONCLUSION

These results suggest that the expected competition between LCn-3PUFA and n-6PUFA at the absorption level is unlikely; therefore competition at the enzymatic level should be primarily responsible for differences in their metabolic and clinical effects. Trial registered with the Australia New Zealand Trial registry as ACTRN12612000654853.

Relationship between polyunsaturated fatty acid levels in maternal diets and human milk in the first month post-partum

BACKGROUND

The present study evaluated the relationship between dietary fatty acid (FA) intakes and human milk FA levels.

METHODS

Healthy lactating women (n = 514) from Northern China participated in the study. Dietary intake was assessed with a 24-h dietary recall questionnaire and evaluated using golden key maternal nutrition software (Wincome, Shanghai, China) and China Food Composition 2009. Human milk FA composition was determined by gas chromatography.

RESULTS

The maternal daily median intakes of linoleic acid (LA), α-linolenic acid (ALA) and arachidonic acid (AA) were 19.93 g, 3.08 g and 16.33 mg, respectively. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) intakes were below the recommended levels. FA levels in 100 g of human milk were 0.363 g LA, 0.038 g γ-linolenic acid (GLA), 0.052 g dihomo γ-linolenic acid (DGLA), 0.144 g ALA, 0.079 g AA, 0.007 g EPA, 0.018 g docosatetraenoic acid (DTA) and 0.048 g DHA. Multiple linear regression analysis revealed that human milk DGLA levels were negatively correlated with dietary LA intake (β = -0.223, P = 0.030), and human milk GLA and DTA levels were negatively correlated with dietary ALA intake (β = -2.189, P = 0.031; β = -2.252, P = 0.027) after adjusting for possible confounding factors.

CONCLUSIONS

The results of the present study suggest the presence of competitive interactions between n-3 fatty acids (ALA) and n-6 fatty acids (GLA and DTA).

Potential programming of selected cardiometabolic risk factors at childhood by maternal polyunsaturated fatty acid availability in the MEFAB cohort

BACKGROUND

Increasing evidence suggests that long-chain polyunsaturated fatty acid (LCPUFA) availability in utero could program later health.

OBJECTIVE

The objective of the study was to explore whether prenatal LCPUFA availability could be involved in programming cardiometabolic disease risk at childhood.

METHODS

Data of 242 mother-child pairs from the Maastricht Essential Fatty Acid Birth (MEFAB) cohort were used. Multi-variable linear regression analysis was applied to identify associations between maternal LCPUFA concentrations around weeks 11, 22 and 32 of pregnancy and at time of delivery and cardiometabolic risk factors of their children (glucose metabolism, blood lipids, and blood pressure) at age 7.

RESULTS

Maternal eicosapentaenoic acid (20:5n-3) at week 11 of pregnancy was negatively associated with children׳s glucose (B=-0.34mmol/L; 95% CI: -0.56, -0.12). Positive associations were found between maternal linoleic acid (18:2n-6) at time of delivery and children׳s proinsulin (B=0.25pmol/L; 95% CI: 0.08, 0.41); maternal 3-docosapentaenoic acid (22:5n-3) at week 11 and children׳s total cholesterol (B=1.23mmol/L; 95% CI: 0.45, 2.01) and low-density-lipoprotein cholesterol (B=1.12mmol/L; 95% CI: 0.42, 1.82); and maternal osbond acid (22:5n-6) at week 22 and tetracosadienoic acid (24:2n-6) at week 32 and children׳s diastolic blood pressure (B=16.86mmHg; 95% CI: 7.63, 26.08 and B=17.75mmHg; 95% CI: 6.37, 29.94, respectively).

CONCLUSION

Our findings suggest that maternal omega-6 (n-6) fatty acids may be of particular importance in relation to children׳s glucose metabolism and blood pressure, whereas omega-3 (n-3) fatty acids seem particularly related to blood lipids at childhood. In general, the strength of the associations appeared stronger with fatty acid concentrations in early pregnancy compared to late pregnancy.

The Effect of Omega-3 Docosahexaenoic Acid Supplementation on Gestational Length: Randomized Trial of Supplementation Compared to Nutrition Education for Increasing n-3 Intake from Foods

OBJECTIVE

DHA supplementation was compared to nutrition education to increase DHA consumption from fish and DHA fortified foods.

DESIGN

This two-part intervention included a randomized double-blind placebo controlled DHA supplementation arm and a nutrition education arm designed to increase intake of DHA from dietary sources by 300 mg per day.

SETTING

Denver Health Hospitals and Clinics, Denver, Colorado, USA.

POPULATION

871 pregnant women aged 18-40 were recruited between 16 and 20 weeks of gestation of whom 564 completed the study and complete delivery data was available in 505 women and infants.

METHODS

Subjects received either 300 or 600 mg DHA or olive oil placebo or nutrition education.

MAIN OUTCOME VARIABLE

Gestational length.

RESULTS

Gestational length was significantly increased by 4.0-4.5 days in women supplemented with 600 mg DHA per day or provided with nutrition education. Each 1% increase in RBC DHA at delivery was associated with a 1.6-day increase in gestational length. No significant effects on birth weight, birth length, or head circumference were demonstrated. The rate of early preterm birth (1.7%) in those supplemented with DHA (combined 300 and 600 mg/day) was significantly lower than in controls.

CONCLUSION

Nutrition education or supplementation with DHA can be effective in increasing gestational length.

Lipid Quality in Infant Nutrition: Current Knowledge and Future Opportunities

Dietary lipids are key for infants to not only meet their high energy needs but also fulfill numerous metabolic and physiological functions critical to their growth, development, and health. The lipid composition of breast milk varies during lactation and according to the mother's diet, whereas the lipid composition of infant formulae varies according to the blend of different fat sources. This report compares the compositions of lipids in breast milk and infant formulae, and highlights the roles of dietary lipids in term and preterm infants and their potential biological and health effects. The major differences between breast milk and formulae lie in a variety of saturated fatty acids (such as palmitic acid, including its structural position) and unsaturated fatty acids (including arachidonic acid and docosahexaenoic acid), cholesterol, and complex lipids. The functional outcomes of these differences during infancy and for later child and adult life are still largely unknown, and some of them are discussed, but there is consensus that opportunities exist for improvements in the qualitative lipid supply to infants through the mother's diet or infant formulae. Furthermore, research is required in several areas, including the needs of term and preterm infants for long-chain polyunsaturated fatty acids, the sites of action and clinical effects of lipid mediators on immunity and inflammation, the role of lipids on metabolic, neurological, and immunological outcomes, and the mechanisms by which lipids act on short- and long-term health.

Postprandial lipid responses do not differ following consumption of butter or vegetable oil when consumed with omega-3 polyunsaturated fatty acids

Dietary saturated fat (SFA) intake has been associated with elevated blood lipid levels and increased risk for the development of chronic diseases. However, some animal studies have demonstrated that dietary SFA may not raise blood lipid levels when the diet is sufficient in omega-3 polyunsaturated fatty acids (n-3PUFA). Therefore, in a randomised cross-over design, we investigated the postprandial effects of feeding meals rich in either SFA (butter) or vegetable oil rich in omega-6 polyunsaturated fatty acids (n-6PUFA), in conjunction with n-3PUFA, on blood lipid profiles [total cholesterol, low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C) and triacylglycerol (TAG)] and n-3PUFA incorporation into plasma lipids over a 6-h period. The incremental area under the curve for plasma cholesterol, LDL-C, HDL-C, TAG and n-3PUFA levels over 6 h was similar in the n-6PUFA compared to SFA group. The postprandial lipemic response to saturated fat is comparable to that of n-6PUFA when consumed with n-3PUFA; however, sex-differences in response to dietary fat type are worthy of further attention.

Linoleic and docosahexaenoic acids in human milk have opposite relationships with cognitive test performance in a sample of 28 countries

Polyunsaturated fatty acids play critical roles in brain development and function, and their levels in human breast milk closely reflect the long-term diet. The fatty acid contents of human milk samples from 28 countries were used to predict averaged 2009 and 2012 test scores in mathematics, reading, and science from the Program for International Student Assessment. All test scores were positively related to milk docosahexaenoic acid (r=0.48 to 0.55), and negatively related to linoleic acid (r=-0.28 to -0.56). Together, these two human milk fatty acids explained 46% to 48% of the variance in scores, with no improvement in predictive power when socioeconomic variables were added to the regression. The (log) ratio of linoleic to arachidonic acid was negatively related to scores (r=-0.45 to -0.48). Statistical effects were similar for the two sexes. In a separate US sample, estimated dietary linoleic was negatively related to the levels of all long-chain n-3 and n-6 plasma fatty acids. High levels of dietary linoleic may impair cognition by decreasing both docosahexaenoic and arachidonic acids in the brain.

Identification of quantitative trait loci controlling linolenic acid concentration in PI483463 (Glycine soja)

KEY MESSAGE

The QTLs controlling alpha-linolenic acid concentration from wild soybean were mapped on nine soybean chromosomes with various phenotypic variations. New QTLs for alpha-linolenic acid were detected in wild soybean. Alpha-linolenic acid (ALA) is a polyunsaturated fatty acid desired in human and animal diets. Some wild soybean (Glycine soja) genotypes are high in ALA. The objective of this study was to identify quantitative trait loci (QTLs) controlling ALA concentration in a wild soybean accession, PI483463. In total, 188 recombinant inbred lines of F5:6, F5:7, and F5:8 generations derived from a cross of wild soybean PI483463 (~15 % ALA) and cultivar Hutcheson (~9 % ALA) were planted in four environments. Harvested seeds were used to measure fatty acid concentration. Single nucleotide polymorphism markers of the universal soybean linkage panel (USLP 1.0) and simple sequence repeat markers were used for molecular genotyping. Nine putative QTLs were identified that controlled ALA concentration by model-based composite interval mapping and mapped to different soybean chromosomes. The QTLs detected in four environments explained 2.4-7.9 % of the total phenotypic variation (PV). Five QTLs, qALA5_3, qALA6_1, qALA14_1, qALA15_1, and qALA17_1, located on chromosomes 5, 6, 14, 15, and 17 were identified by model-based composite interval mapping and composite interval mapping in two individual environments. Among them, qALA6_1 showed the highest contribution to the PV with 10.0-10.2 % in two environments. The total detected QTLs for additive and epistatic effects explained 52.4 % of the PV for ALA concentration. These findings will provide useful information for understanding genetic structure and marker-assisted breeding programs to increase ALA concentration in seeds derived from wild soybean PI483463.

Dietary omega-6 fatty acid lowering increases bioavailability of omega-3 polyunsaturated fatty acids in human plasma lipid pools

BACKGROUND

Dietary linoleic acid (LA, 18:2n-6) lowering in rats reduces n-6 polyunsaturated fatty acid (PUFA) plasma concentrations and increases n-3 PUFA (eicosapentaenoic (EPA) and docosahexaenoic acid (DHA)) concentrations.

OBJECTIVE

To evaluate the extent to which 12 weeks of dietary n-6 PUFA lowering, with or without increased dietary n-3 PUFAs, alters unesterified and esterified plasma n-6 and n-3 PUFA concentrations in subjects with chronic headache.

DESIGN

Secondary analysis of a randomized trial. Subjects with chronic headache were randomized for 12 weeks to (1) average n-3, low n-6 (L6) diet; or (2) high n-3, low n-6 LA (H3-L6) diet. Esterified and unesterified plasma fatty acids were quantified at baseline (0 weeks) and after 12 weeks on a diet.

RESULTS

Compared to baseline, the L6 diet reduced esterified plasma LA and increased esterified n-3 PUFA concentrations (nmol/ml), but did not significantly change plasma arachidonic acid (AA, 20:4n-6) concentration. In addition, unesterified EPA concentration was increased significantly among unesterified fatty acids. The H3-L6 diet decreased esterified LA and AA concentrations, and produced more marked increases in esterified and unesterified n-3 PUFA concentrations.

CONCLUSION

Dietary n-6 PUFA lowering for 12 weeks significantly reduces LA and increases n-3 PUFA concentrations in plasma, without altering plasma AA concentration. A concurrent increase in dietary n-3 PUFAs for 12 weeks further increases n-3 PUFA plasma concentrations and reduces AA.

Proceedings from the 2013 Canadian Nutrition Society Conference on Advances in Dietary Fats and Nutrition

The science of lipid research continues to rapidly evolve and change. New knowledge enhances our understanding and perspectives on the role of lipids in health and nutrition. However, new knowledge also challenges currently held opinions. The following are the proceedings of the 2013 Canadian Nutrition Society Conference on the Advances in Dietary Fats and Nutrition. Content experts presented state-of-the-art information regarding our understanding of fish oil and plant-based n-3 polyunsaturated fatty acids, nutrigenomics, pediatrics, regulatory affairs, and trans fats. These important contributions aim to provide clarity on the latest advances and opinions regarding the role of different types of fats in health.

Saturated fat consumption may not be the main cause of increased blood lipid levels

Consumption of foods rich in saturated fatty acids (SFA) has often been associated with elevated blood lipid levels and consequently with risk for chronic diseases, including coronary heart disease. However, epidemiological and interventional studies on this topic are contradictory. While some studies have established a positive link, other studies have failed to show a significant association between saturated fat consumption and blood lipid levels, and others have even found an inverse association. Moreover, studies using animal models have demonstrated that dietary saturated fats raise blood lipid (cholesterol and triglycerides) levels only when the diet is deficient in omega-3 polyunsaturated fatty acids (n-3PUFA). The n-3PUFA are known for their potential in the management of hyperlipidaemia for the prevention of coronary heart disease, as well as for their anti-arrhythmic, anti-aggregatory and anti-inflammatory potential. We believe that with an adequate consumption of n-3PUFA dietary saturated fat may not result in elevated blood lipid levels. Therefore, we critically evaluated the literature regarding saturated fat and blood lipid level, with an emphasis on the role of n-3PUFA on this relationship. Evidence from animal studies and few clinical trials lead to the hypothesis that there are beneficial or neutral effects of saturated fatty acids when combined with recommended levels of n-3PUFA in the diet. However, an intervention focusing on the background fat when the volunteers' diet is supplemented with n-3PUFA is yet to be done. Proving the authenticity of this hypothesis would mean a substantial change in public health messages regarding saturated fats and their health effects; and also a change in the strategies related to prevention of chronic cardiac and artery diseases.

Dietary fat in relation to erythrocyte fatty acid composition in men

Erythrocyte membrane fatty acid (EMFA) composition is used in the validation of food frequency questionnaires (FFQ) and the evaluation of dietary fat quality. In this cross-sectional study we aimed to investigate associations of diet with EMFA. Altogether, 1,033 randomly selected Finnish men, aged from 47 to 75 years filled in a FFQ and their EMFA composition was analyzed. Marine polyunsaturated fatty acid (PUFA) intake correlated positively with erythrocyte eicosapentaenoic and docosahexaenoic acids (r(s) = 0.415 and r(s) = 0.340, respectively, P < 0.001) and inversely with all n-6 PUFA analyzed (P < 0.001). PUFA intake from spreads and cooking fats correlated positively with alpha-linolenic (ALA), linoleic (LNA) and nervonic acids (r(s) = 0.229, r(s) = 0.160 and r(s) = 0.143, respectively, P < 0.001). Milk fat intake was associated with myristic and behenic acids (r(s) = 0.186 and r(s) = 0.132, respectively P < 0.001). Butter users had lower ALA and LNA proportions (mol%) than non-users (0.16 ± 0.04 vs. 0.19 ± 0.05, P < 0.001 and 7.77 ± 1.02 vs. 8.12 ± 1.11, P = 0.001). Higher PUFA intake from meat was related to decreased long-chain n-3 (P < 0.001) and increased n-6 PUFA (P < 0.001) proportions. In conclusion, EMFA composition reflects particularly well the intakes of n-3 PUFA, whereas other associations remained lower. Yet, all main sources of dietary fat were related with EMFA. The dietary effect on the nervonic acid proportion was confirmed.

Targeted alteration of dietary n-3 and n-6 fatty acids for the treatment of chronic headaches: a randomized trial

Omega-3 and n-6 fatty acids are biosynthetic precursors to lipid mediators with antinociceptive and pronociceptive properties. We conducted a randomized, single-blinded, parallel-group clinical trial to assess clinical and biochemical effects of targeted alteration in dietary n-3 and n-6 fatty acids for treatment of chronic headaches. After a 4-week preintervention phase, ambulatory patients with chronic daily headache undergoing usual care were randomized to 1 of 2 intensive, food-based 12-week dietary interventions: a high n-3 plus low n-6 (H3-L6) intervention, or a low n-6 (L6) intervention. Clinical outcomes included the Headache Impact Test (HIT-6, primary clinical outcome), Headache Days per month, and Headache Hours per day. Biochemical outcomes included the erythrocyte n-6 in highly unsaturated fatty acids (HUFA) score (primary biochemical outcome) and bioactive n-3 and n-6 derivatives. Fifty-six of 67 patients completed the intervention. Both groups achieved targeted intakes of n-3 and n-6 fatty acids. In intention-to-treat analysis, the H3-L6 intervention produced significantly greater improvement in the HIT-6 score (-7.5 vs -2.1; P<0.001) and the number of Headache Days per month (-8.8 vs -4.0; P=0.02), compared to the L6 group. The H3-L6 intervention also produced significantly greater reductions in Headache Hours per day (-4.6 vs -1.2; P=0.01) and the n-6 in HUFA score (-21.0 vs -4.0%; P<0.001), and greater increases in antinociceptive n-3 pathway markers 18-hydroxy-eicosapentaenoic acid (+118.4 vs +61.1%; P<0.001) and 17-hydroxy-docosahexaenoic acid (+170.2 vs +27.2; P<0.001). A dietary intervention increasing n-3 and reducing n-6 fatty acids reduced headache pain, altered antinociceptive lipid mediators, and improved quality-of-life in this population.

Maternal milk DHA content predicts cognitive performance in a sample of 28 nations

Convergent evidence from neuronal biology and hominin brain hypertrophy suggests that omega-3 fatty acids are a limiting resource for neural and cognitive development in Homo sapiens, and therefore that children from populations with higher omega-3 availability should display superior cognitive performance. Using multiple regression, we tested this prediction in a sample of 28 countries, with Programme for International Student Assessment (PISA) math scores in 2009 as an index of cognitive performance, and country-specific breast milk levels of omega-3 docosahexaenoic acid (DHA) as an index of omega-3 availability. Breast milk DHA makes a highly significant contribution to math scores (β = 0.462, P = 0.006), greater in magnitude than the control variables of per capita Gross Domestic Product (PCGDP) and educational expenditures per pupil. Together, dietary fish (positively) and total fat (negatively) explain 61% of the variance in maternal milk DHA in a larger sample of 39 countries.

Low-n-6 and low-n-6 plus high-n-3 diets for use in clinical research

Few trials have evaluated the metabolic effects and health outcomes of lowering dietary n-6 PUFA. The objectives of the present paper were (1) to report the methods employed to lower dietary n-6 PUFA, while either increasing or maintaining n-3 PUFA intake and (2) to validate our methods with 24 h recalls and erythrocyte fatty acid analyses. A total of sixty-seven subjects were randomised to either (1) an average-n-3 PUFA, low-n-6 PUFA (L6) intervention designed to lower linoleic acid (LA; #2·5% of energy (en%)) and arachidonic acid (#60 mg/d), while maintaining an average US intake of n-3 PUFA or (2) a high-n-3 PUFA, low-n-6 PUFA (H3-L6) intervention designed to lower n-6 LA, while increasing the n-3 PUFA a-linolenic acid (ALA; $1·5 en%) and EPA þ DHA ($1000 mg/d). Pre- and intraintervention nutrient intakes were estimated with six 24 h dietary recalls per subject. Both groups achieved the targeted reductions in dietary LA to #2·5 en% (median LA 2·45 (2·1, 3·1); P,0·001). Intakes of n-3 PUFA did not change for the L6 group. Target increases in n-3 ALA (median 1·6 en%, (1·3, 2·0), P,0·001) and EPA þ DHA (1482 mg, (374, 2558), P,0·001) were achieved in the H3-L6 group. Dietary changes were validated by corresponding changes in erythrocyte n-6 and n-3 fatty acid composition. Dietary LA can be lowered to #2·5 en%, with or without concurrent increases in dietary n-3 PUFA, in an outpatient clinical trial setting using this integrated diet method.

Clinical overview of effects of dietary long-chain polyunsaturated fatty acids during the perinatal period

The current report provides a brief background introducing 30 years of research on long-chain polyunsaturated fatty acids (LC-PUFA) and infant development, but focuses mainly on challenges for future studies. Infants fed formulas containing only vegetable fats were found to have lower docosahexaenoic acid (DHA, 22:6n-3) and arachidonic acid (20:4n-6) status than infants fed human milk. Studies soon focused on efforts to improve LC-PUFA status and evaluate functions suggested by early primate studies of DHA deficiency. Despite evidence for the importance of these fatty acids for development, particularly DHA, several recent meta-analyses conclude dietary supplementation does not enhance development. Future studies should employ (1) more finely grained measures of brain development as opposed to global measures, and (2) tests that evaluate development later in childhood when children are able to be tested on more complex behaviors (if found effective these would also be evidence of early brain programming). (3) Studies are needed to understand the cause of high variability in transfer of DHA to the fetus. (4) Finally, the role of single-nucleotide polymorphisms of the fatty acid desaturase genes 1 and 2 of mother and infant needs study to determine how they affect requirements for these fatty acids by the fetus/infant.

Docosahexaenoic and arachidonic acid levels in extremely low birth weight infants with prolonged exposure to intravenous lipids

OBJECTIVE

To report changes in red blood cell long-chain polyunsaturated fatty acids levels in extremely low birth weight (ELBW) infants relative to duration of intravenous lipid emulsion.

STUDY DESIGN

Serial blood samples were collected from 26 ELBW infants during the first 2 months of life in the neonatal intensive care unit using a prospective cohort study design. The primary outcome was the change in long-chain polyunsaturated fatty acids levels over the study period relative to a duration of intravenous lipid emulsion of either ≤ 28 days or >28 days. Secondary outcomes included parenteral and enteral nutritional exposures as well as prematurity-associated morbidities. Longitudinal regression estimated changes in fatty acid levels between the 2 exposure groups.

RESULTS

Infants with >28 days intravenous lipid emulsion had 36 more days of intravenous lipid emulsion than did those with ≤ 28 days (P < .001). Docosahexaenoic acid significantly decreased over time in all infants and decreased significantly more in infants exposed to intravenous lipid emulsion for >28 days (P = .03). Arachidonic acid significantly decreased over the study period but the decrease was not related to intravenous lipid emulsion duration. Linoleic and α-linolenic acids had significantly larger increases over time in those with longer exposure to intravenous lipid emulsion (P < .01).

CONCLUSION

Docosahexaenoic acid status of ELBW infants declined significantly in the first 2 months of life and the decline was significantly greater in those exposed to intravenous lipid emulsion >28 days compared with those exposed ≤ 28 days.

Low fatty acid concentrations in neonatal cord serum correlate with maternal serum

OBJECTIVE

Lactating women in New Mexico have low levels of important fatty acids relative to reported international data. The objective was to correlate the proportions of long-chain polyunsaturated fatty acids (LCPUFA) in the serum phospholipids in mothers and newborns within the same population.

METHODS

The serum phospholipids of 52 maternal:neonatal pairs were analyzed. Maternal samples from consecutive admissions were collected at hospital admission, and umbilical cord blood samples were collected at delivery. Fatty acid methyl esters were prepared and then separated and quantified by gas-liquid chromatography.

RESULTS

The median maternal percentages of arachidonic acid (AA) (4.9%), eicosapentaenoic acid (EPA) (0.27%) and docosahexaenoic acid (DHA) (2.07%) were below reported international levels. The percentages of AA (9.6%) and DHA (3.2%) in cord serum phospholipids were much higher than maternal samples but remained lower than reported internationally, whereas cord EPA (1.1%) was higher than reported. The highest percentage of DHA in serum phospholipids was found in the Asian subjects (4.21 ± 0.41%), while the American Indian women had the lowest DHA percentage (1.38 ± 0.26%). The maternal DHA percentage was negatively correlated with parity (r = -0.22, p = 0.04).

CONCLUSIONS

In the setting of low maternal levels of important fatty acids, their newborns did not accrue serum levels equivalent to reported international values.

Fatty acids in cardiovascular health and disease: a comprehensive update

Research dating back to the 1950s reported an association between the consumption of saturated fatty acids (SFAs) and risk of coronary heart disease. Recent epidemiological evidence, however, challenges these findings. It is well accepted that the consumption of SFAs increases low-density lipoprotein cholesterol (LDL-C), whereas carbohydrates, monounsaturated fatty acids (MUFAs), and polyunsaturated fatty acids (PUFAs) do not. High-density lipoprotein (HDL)-C increases with SFA intake. Among individuals who are insulin resistant, a low-fat, high-carbohydrate diet typically has an adverse effect on lipid profiles (in addition to decreasing HDL-C, it also increases triglyceride and LDL particle concentrations). Consequently, a moderate fat diet in which unsaturated fatty acids replace SFAs and carbohydrates are not augmented is advised to lower LDL-C; compared with a low-fat diet, a moderate-fat diet will lower triglycerides and increase HDL-C. Now, there is some new evidence that is questioning the health benefits of even MUFAs and PUFAs. In addition, in a few recent studies investigators have also failed to demonstrate expected cardiovascular benefits of marine-derived omega-3 fatty acids. To clarify the clinical pros and cons of dietary fats, the National Lipid Association held a fatty acid symposium at the 2011 National Lipid Association Scientific Sessions. During these sessions, the science regarding the effects of different fatty acid classes on coronary heart disease risk was reviewed.

Gestational age dependent changes of the fetal brain, liver and adipose tissue fatty acid compositions in a population with high fish intakes

INTRODUCTION

There are no data on the intrauterine fatty acid (FA) compositions of brain, liver and adipose tissue of infants born to women with high fish intakes.

SUBJECTS AND METHODS

We analyzed the brain (n=18), liver (n=14) and adipose tissue (n=11) FA compositions of 20 stillborn infants with different gestational ages (range 8-38 weeks) born to Tanzanian women with low linoleic acid (LA) intakes and high intakes of docosahexaenoic (DHA) and arachidonic (AA) acids from local fish.

RESULTS AND DISCUSSION

With advancing gestation, brain saturated-FA (SAFA; in g/100g FA), polyunsaturated-FA (PUFA), DHA, 20:3ω6, 22:4ω6 and 22:5ω6 increased, while monounsaturated-FA (MUFA), 20:3ω9, 22:3ω9 and AA decreased. Decreasing brain AA might be caused by increasing AA-metabolism to 20:3ω6, 22:4ω6 and 22:5ω6. In the liver, SAFA, PUFA and LA increased, while MUFA decreased with gestation. The steep increase of (mostly de novo synthesized) SAFA in adipose tissue coincided with relative decreases of MUFA, PUFA, DHA, LA and AA with advancing gestation. Compared to Western infants, the currently studied African infants had higher DHA, lower AA, and a higher DHA/AA-ratio in brain and adipose tissue, while the LA content of adipose tissue was lower.

CONCLUSION

The low LA and high DHA and AA intakes by the mothers of these infants might support optimal α-linolenic (ALA) vs. LA competition for Δ5D and Δ6D-activities and DHA vs. AA antagonism. Conversely, the Western diet, characterized by high LA and lower DHA and AA intakes, might disturb these evolutionary conserved mechanisms aiming at an optimal ω3/ω6-balance.

Motor, mental and behavioral developments in infancy are associated with fatty acid pattern in breast milk and plasma of premature infants

The objective of this study was to investigate any association between infants' early development and PUFA concentrations in early breast milk and infants' plasma phospholipids at 44 weeks gestational age. Fifty-one premature infants were included. The quality of general movement was assessed at 3 months, and motor, mental and behavioral development at 3, 6, 10 and 18 months corrected age using Bayley's Scales of Infant Development (BSID-II). Linoleic acid, the major n-6/n-3 FA ratios, Mead acid and the EFA deficiency index in early breast milk were negatively associated with development up to 18 months of age. DHA and AA, respectively, in infants' plasma phospholipids was positively, but the AA/DHA ratio negatively, associated with development from 6 to 18 months of age. Our data suggest that the commonly found high n-6 concentration in breast milk is associated with less favorable motor, mental and behavioral development up to 18 months of age.

Impact of maternal dietary n-3 and n-6 fatty acids on milk medium-chain fatty acids and the implications for neonatal liver metabolism

Levels of n-6, n-3, and medium-chain fatty acids (MCFA) in milk are highly variable. Higher carbohydrate intakes are associated with increased mammary gland MCFA synthesis, but the role of unsaturated fatty acids for milk MCFA secretion is unclear. This study addressed whether n-6 and n-3 fatty acids, which are known to inhibit hepatic fatty acid synthesis, influence MCFA in rat and human milk and the implications of varying MCFA, n-6, and n-3 fatty acids in rat milk for metabolic regulation in the neonatal liver. Rats were fed a low-fat diet or one of six higher-fat diets, varying in 16:0, 18:1n-9, 18:2n-6, 18:3n-3, and long-chain (LC) n-3 fatty acids. Higher maternal dietary 18:2n-6 or 18:3n-3 did not influence milk MCFA, but lower maternal plasma triglycerides, due to either a low-fat or a high-fat high-LC n-3 diet led to higher milk MCFA. MCFA levels were inversely associated with 18:1n-9, 18:2n-6, and 18:3n-3 in human milk, likely reflecting the association between dietary total fat and unsaturated fatty acids. High LC n-3 fatty acid in rat milk was associated with lower hepatic Pklr, Acly, Fasn, and Scd1 and higher Hmgcs2 in the milk-fed rat neonate, with no effect of milk 18:1n-9, 18:2n-6, or MCFA. These studies show that the dietary fatty acid composition does not impact MCFA secretion in milk, but the fatty acid composition of milk, particularly the LC n-3 fatty acid, is relevant to hepatic metabolic regulation in the milk-fed neonate.

A maternal erythrocyte DHA content of approximately 6 g% is the DHA status at which intrauterine DHA biomagnifications turns into bioattenuation and postnatal infant DHA equilibrium is reached

Purpose

Higher long-chain polyunsaturated fatty acids (LCP) in infant compared with maternal lipids at delivery is named biomagnification. The decline of infant and maternal docosahexaenoic acid (DHA) status during lactation in Western countries suggests maternal depletion. We investigated whether biomagnification persists at lifelong high fish intakes and whether the latter prevents a postpartum decline of infant and/or maternal DHA status.

Methods

We studied 3 Tanzanian tribes with low (Maasai: 0/week), intermediate (Pare: 2–3/week), and high (Sengerema: 4–5/week) fish intakes. DHA and arachidonic acid (AA) were determined in maternal (m) and infant (i) erythrocytes (RBC) during pregnancy (1st trimester n = 14, 2nd = 103, 3rd = 88), and in mother–infant pairs at delivery (n = 63) and at 3 months postpartum (n = 104).

Results

At delivery, infants of all tribes had similar iRBC-AA which was higher than, and unrelated to, mRBC-AA. Transplacental DHA biomagnification occurred up to 5.6 g% mRBC-DHA; higher mRBC-DHA was associated with “bioattenuation” (i.e., iRBC-DHA < mRBC-DHA). Compared to delivery, mRBC-AA after 3 months was higher, while iRBC-AA was lower. mRBC-DHA after 3 months was lower, while iRBC-DHA was lower (low fish intake), equal (intermediate fish intake), and higher (high fish intake) compared to delivery. We estimated that postpartum iRBC-DHA equilibrium is reached at 5.9 g%, which corresponds to a mRBC-DHA of 6.1 g% throughout pregnancy.

Conclusion

Uniform high iRBC-AA at delivery might indicate the importance of intrauterine infant AA status. Biomagnification reflects low maternal DHA status, and bioattenuation may prevent intrauterine competition of DHA with AA. A mRBC-DHA of about 6 g% during pregnancy predicts maternal–fetal equilibrium at delivery, postnatal iRBC-DHA equilibrium, but is unable to prevent a postnatal mRBC-DHA decline.

A novel FAD2-1 A allele in a soybean plant introduction offers an alternate means to produce soybean seed oil with 85% oleic acid content

The alteration of fatty acid profiles in soybean to improve soybean oil quality has been a long-time goal of soybean researchers. Soybean oil with elevated oleic acid is desirable because this monounsaturated fatty acid improves the nutrition and oxidative stability of soybean oil compared to other oils. In the lipid biosynthetic pathway, the enzyme fatty acid desaturase 2 (FAD2) is responsible for the conversion of oleic acid precursors to linoleic acid precursors in developing soybean seeds. Two genes encoding FAD2-1A and FAD2-1B were identified to be expressed specifically in seeds during embryogenesis and have been considered to hold an important role in controlling the seed oleic acid content. A total of 22 soybean plant introduction (PI) lines identified to have an elevated oleic acid content were characterized for sequence mutations in the FAD 2-1A and FAD2-1B genes. PI 603452 was found to contain a deletion of a nucleotide in the second exon of FAD2-1A. These important SNPs were used in developing molecular marker genotyping assays. The assays appear to be a reliable and accurate tool to identify the FAD 2-1A and FAD2-1B genotype of wild-type and mutant plants. PI 603452 was subsequently crossed with PI 283327, a soybean line that has a mutation in FAD2-1B. Interestingly, soybean lines carrying both homozygous insertion/deletion mutation (indel) FAD2-1A alleles and mutant FAD2-1B alleles have an average of 82-86% oleic acid content, compared to 20% in conventional soybean, and low levels of linoleic and linolenic acids. The newly identified indel mutation in the FAD2-1A gene offers a simple method for the development of high oleic acid commercial soybean varieties.

The relation between the omega-3 index and arachidonic acid is bell shaped: synergistic at low EPA+DHA status and antagonistic at high EPA+DHA status

INTRODUCTION

The relation between docosahexaenoic (DHA) and eicosapentaenoic (EPA) vs. arachidonic acid (AA) seems characterized by both synergism and antagonism.

MATERIALS AND METHODS

Investigate the relation between EPA+DHA and AA in populations with a wide range of EPA+DHA status and across the life cycle. EPA+DHA and AA were determined in erythrocytes (RBC; n=1979), umbilical arteries (UA; n=789) and umbilical veins (UV; n=785).

RESULTS

In all compartments, notably RBC, the relation between EPA+DHA and AA appeared bell-shaped. Populations with low RBC-EPA+DHA (<2g%) exhibited positive relationships; those with high RBC-EPA+DHA (>8g%) negative relationships. Antagonism in UA and UV could not be demonstrated.

CONCLUSION

Both synergism and antagonism might aim at a balance between ω6 and ω3 long-chain polyunsaturated fatty acid (LCP) to maintain homeostasis. Synergism might be a feature of low LCPω3 status. AA becomes suppressed by antagonism from an RBC-EPA+DHA >8g%.

Differences in arachidonic acid levels and fatty acid desaturase (FADS) gene variants in African Americans and European Americans with diabetes or the metabolic syndrome

Over the past 50 years, increases in dietary n-6 PUFA, such as linoleic acid, have been hypothesised to cause or exacerbate chronic inflammatory diseases. The present study examines an individual's innate capacity to synthesise n-6 long-chain PUFA (LC-PUFA) with respect to the fatty acid desaturase (FADS) locus in Americans of African and European descent with diabetes or the metabolic syndrome. Compared with European Americans (EAm), African Americans (AfAm) exhibited markedly higher serum levels of arachidonic acid (AA) (EAm 7·9 (sd 2·1), AfAm 9·8 (sd 1·9) % of total fatty acids; P < 2·29 × 10⁻⁹) and the AA:n-6-precursor fatty acid ratio, which estimates FADS1 activity (EAm 5·4 (sd 2·2), AfAm 6·9 (sd 2·2); P = 1·44 × 10⁻⁵). In all, seven SNP mapping to the FADS locus revealed strong association with AA, EPA and dihomo-γ-linolenic acid (DGLA) in the EAm. Importantly, EAm homozygous for the minor allele (T) had significantly lower AA levels (TT 6·3 (sd 1·0); GG 8·5 (sd 2·1); P = 3·0 × 10⁻⁵) and AA:DGLA ratios (TT 3·4 (sd 0·8), GG 6·5 (sd 2·3); P = 2·2 × 10⁻⁷) but higher DGLA levels (TT 1·9 (sd 0·4), GG 1·4 (sd 0·4); P = 3·3 × 10⁻⁷) compared with those homozygous for the major allele (GG). Allele frequency patterns suggest that the GG genotype at rs174537 (associated with higher circulating levels of AA) is much higher in AfAm (0·81) compared with EAm (0·46). Similarly, marked differences in rs174537 genotypic frequencies were observed in HapMap populations. These data suggest that there are probably important differences in the capacity of different populations to synthesise LC-PUFA. These differences may provide a genetic mechanism contributing to health disparities between populations of African and European descent.

Dietary lipids from an evolutionary perspective: sources, structures and functions

Lipids are a complex group of biomolecules whose precise functions remain poorly understood. As a result of this poor understanding, it is difficult to make mechanistically based recommendations for appropriate dietary intakes. It is equally difficult to develop methods that are capable of diagnosing functional impairments because of insufficiencies or excesses in particular fatty acids. Lipids are abundant building blocks of cellular membranes, supply components for lipid particle assembly and substrates for metabolic fuel, and provide a precursor pool for an astonishingly diverse range of signalling molecules. In each of these broad functions, the functional consequences of different structures of fatty acids are not fully understood. According to research on membrane functions through early evolution, docosahexaenoic acid provides two biophysical properties to membranes - accelerating the lateral motion of lipids and proteins within the plane of the membrane and simultaneously slowing the rate of diffusion/leakage of charged species across the plane of the membrane. The range of fatty acid structures used as substrates for assembly of either lipoproteins or milk fat globules is broad, yet the functional consequences of differences are not known. Different lipids signal into a remarkable range of biological processes. Saturated and monounsaturated fatty acids are becoming recognized as signal molecules in their own right. The complex composition of human milk lipids implies that diets with a diversity of fatty acids in complex lipid forms and structures is more beneficial than a narrow range of any particular group of fatty acids.