Docosahexaenoic acid and cognitive function: Is the link mediated by the autonomic nervous system?

DHA Supplementation During Pregnancy Enhances Maternal Vagally Mediated Cardiac Autonomic Control in Humans

BACKGROUND

DHA is an essential omega-3 (ω-3; n-3) fatty acid that has well-established benefits for the fetus. DHA also has the potential to influence the health of the mother, but this area is understudied.

OBJECTIVES

The objective of this secondary analysis was to determine if DHA was related to maternal heart rate (HR) and heart rate variability (HRV) metrics in a large cohort of pregnant women.

METHODS

In the parent trial (1R01HD086001) eligible participants (≥18 y old, English speaking, carrying a singleton pregnancy, 12-20 wk of gestation) were randomly assigned to consume 200 mg/d or 800 mg/d DHA for the duration of their pregnancy (n = 300). Weight, blood pressure, and magnetocardiograms (MCGs) were collected at 32 wk and 36 wk of gestation (n = 221). Measures of HR and HRV in time-, frequency-, and nonlinear-domains were determined from the isolated maternal MCG. Treatment group and timepoint were examined as predictors in association with HR and HRV metrics using random-intercept mixed-effects ANOVA unadjusted and adjusted models accounting for weight and dietary DHA intake.

RESULTS

Women receiving the higher dose of DHA (800 mg/d) during pregnancy had lower HR, lower sympathetic index, higher vagally mediated HRV indices, and greater HRV complexity when compared with the women who received the lower dose (200 mg/d; all P < 0.05). All the dose relations remained significant even after controlling for the effect of time, maternal weight, and dietary DHA intake.

CONCLUSIONS

DHA supplementation increases vagal tone in pregnant women. Longitudinal studies examining the potential link between DHA, enhanced vagal tone, and reported reduction in early preterm birth are warranted.

Prenatal docosahexaenoic acid supplementation has long-term effects on childhood behavioral and brain responses during performance on an inhibitory task

Introduction: Offsprings from a prenatal docosahexaenoic acid (DHA) supplementation trial, in which pregnant women were assigned to placebo or 600mg DHA/day, were followed to determine the effect of prenatal DHA supplementation on the behavior and brain function at 5.5 years (n=81 placebo, n=86 supplemented).Methods: Event-related potentials (ERP) were recorded during a visual task requiring a button press (Go) to frequent target stimuli and response inhibition to the rare stimuli (No-Go). Univariate ANOVAs were used to test differences between group and sex for behavioral measures. ERP differences were tested using a three-way mixed-design multivariate analysis of variance (MANOVA).Results: There was a significant sex × group interaction for hit rate and errors of omission; there was no difference between males and females in the placebo group, but DHA males outperformed DHA females. Males overall and the placebo group made more errors requiring response inhibition; DHA females were significantly better than placebo females and DHA males. ERP P2 amplitude was larger in the DHA group. A significant N2 amplitude condition effect was observed in females and DHA group males, but not in placebo group males.Discussion: Prenatal DHA supplementation improved inhibitory performance overall, especially for females in the DHA group, possibly accounting for their conservative behavior during Go trials. Development of brain regions responsible for visual processing may be sensitive to maternal DHA status, evidenced by greater P2 amplitude. Males may benefit more from maternal DHA supplementation, indicated by the N2 condition effect seen only in males in the DHA group.

Chronotropic effects and mechanisms of long-chain omega-3 polyunsaturated fatty acids on heartbeat: the latest insights

The roles of the resting heart rate (RHR) have been actively investigated and increasingly recognized in recent decades, because of the growing evidence that fast RHR is associated with and predicts the risk of developing cardiovascular and metabolic disorders, as well as all-cause mortality. Long-chain omega-3 polyunsaturated fatty acids (PUFAs) (eg, eicosapentaenoic acid and docosahexaenoic acid) have been shown to have chronotropic effects on heartbeat in both healthy people and patients with various disease conditions. The aims of this review are (1) to briefly summarize the importance of elevated RHR in disease pathogenesis and mortality; (2) to provide an update on the negative chronotropic effect of omega-3 PUFAs on the heart; (3) to highlight how omega-3 PUFAs regulate heart rate through the autonomic nervous system - a central control mechanism; and (4) to highlight how omega-3 PUFAs modulate the trans-membrane ionic channels in cardiomyocytes - a fundamental mechanism of cardiac automaticity. Eicosapentaenoic acid and docosahexaenoic acid are nutrients derived from some aquatic organisms, and they can also be converted from digested oily seeds and nuts of some terrestrial plants in the body. The consumption of omega-3 PUFAs for RHR reduction represents a lifestyle modification for risk factor management and promises nutritional benefits for public health improvement.

Maternal long-chain polyunsaturated fatty acid status during early pregnancy: Association with child behavioral problems and the role of autonomic nervous system activity

BACKGROUND & AIMS

The prenatal environment, including availability of critical nutrients, has a profound impact on offspring development. The present study examined the association between maternal long-chain polyunsaturated fatty acid (LC-PUFA) status during pregnancy and later child behavioral problems at the age of 5-6 years. In light of evidence of autonomic nervous system (ANS) dysregulation in some behavioral problems, study further tested if the above association is statistically mediated by cardiac ANS activity.

METHODS

Data was collected as part of the Amsterdam Born Children and their Development-study and complete data were available for 1717 mothers and their offspring. Maternal LC-PUFA status was assessed during early pregnancy (mean gestation = 12.7, SD = 2.5 weeks) and quantified as levels of docosahexenoic acid (DHA), arachidonic acid (AA), eicosapentaenoic acid (EPA), as well as the ratio of n-6:n-3 fatty acids. Child emotional problems and peer problems (internalizing problems), as well as conduct problems and inattention/hyperactivity (externalizing problems), were assessed using the Strengths and Difficulties Questionnaire as rated by the mother and teacher at 5-6 years. Child cardiac respiratory sinus arrhythmia (RSA), pre-ejection period (PEP), and heart rate (HR) were utilized as measures of ANS activity at 5-6 years.

RESULTS

The results confirmed an association between maternal LC-PUFA status and internalizing behavioral problems as rated by the mother, as shown for DHA (β = -0.11;p < 0.01), EPA (β = -0.22;p < 0.05), and n-6:n-3 LC-PUFA (β = 0.17;p < 0.01). Statistical mediation was only demonstrated for HR. No associations were observed between LC-PUFA status and externalizing behavioral problems.

CONCLUSIONS

The present results are consistent with a role of maternal LC-PUFA status in internalizing behavioral problems as rated by the mother. These results were not observed when problem behavior was rated by the teacher. Analyses did not yield strong evidence supporting ANS activity as a possible mediator in this relationship.

Effects of Continuous Intake of Rosemary Extracts on Mental Health in Working Generation Healthy Japanese Men: Post-Hoc Testing of a Randomized Controlled Trial

We previously performed a 4 week interventional trial that suggested that continuous intake of rosemary extract improves the mood states, fatigue, and cognitive function of working generation healthy adult Japanese men. However, the severity of depression in participants in our previous study was relatively mild. Therefore, in the present study, a post-hoc analysis of our previous study was conducted, limited to participants whose total mood disturbance (TMD) scores, which indicate greater mood disturbance, were above the median at baseline, to evaluate whether rosemary extract was effective for individuals with poor mental health. Following the intervention, the scores of TMD and “Confusion-Bewilderment” were significantly decreased (both p < 0.05), and scores of “Vigor-Activity” were significantly increased in the rosemary group (n = 8) compared with those in the control group (n = 13; p < 0.01). When comparing the scores from pre- and post-intervention, significant improvements in “Tension-Anxiety”, “Vigor-Activity”, “Fatigue on awakening”, “Daytime sleepiness”, and “Psychomotor speed” were observed in the rosemary group only (all p < 0.05). Based on these results, it was expected that rosemary extracts were effective for improving the mental energy and sleep quality of work-age men with poor mental health.

Docosahexaenoic acid levels in erythrocytes and their association with the University Selection Test Outcomes in Chile

The aim of this study was to quantitate the relative impact of DHA and AA levels in erythrocytes, anthropometric parameters and socio-economic status of school-age children, of both genders, graduated from high school in Chile, on the scholastic achievement in the University Selection Test (Prueba de Selección Universitaria, PSU) both language scholastic achievement (LSA) and mathematics scholastic achievement (MSA). A representative sample of 671 school-age young graduated from high school in 2013, 550 and 548 of them took the PSU for LSA and MSA, respectively. Only school-age young with high (n = 91) and low (n = 69) SA in both tests were considered. A total of 122 school-age children agreed to participate in the study and were divided as follows: Group 1: high PSU outcome (n = 70; males n = 48) and Group 2: low PSU outcome (n = 52; males n = 23). Data were analyzed by means of SAS software. Independently of gender, DHA, socio-economic status and head circumference-for-age Z-score were the most relevant parameters explaining both LSA (R²= 0.650; p < 0.0001) and MSA outcomes (R²= 0.700; p < 0.0001). These results can be useful for nutrition, health and education planning, in order to protect children starting from an early age and thus increase their school outcomes.

Maternal n-6 and n-3 fatty acid status during pregnancy is related to infant heart rate and heart rate variability: An exploratory study

Early life heart rate (HR) and heart rate variability (HRV) reflect autonomic system maturation. Intervention with n-3 long chain polyunsaturated fatty acids (LCPUFAs) during pregnancy favorably affects fetal HR and HRV, complementing previous observations for n-3 LCPUFA intervention during infancy. The relationship between maternal fatty acid status during pregnancy and infant HR/HRV has not previously been assessed. The aim of this study was to explore associations between maternal n-6 and n-3 fatty acid status during pregnancy and infant HR and HRV at 2 weeks, 4 months, and 6 months of age using linear regression models. Maternal n-3 fatty acids were inversely related to infant HR and positively related to HRV. Conversely, maternal n-6 fatty acids were positively related to infant HR and inversely related to HRV. These data build on existing literature evidencing a role for n-3 fatty acids in accelerating autonomic development and link n-6 fatty acids to HR/HRV.

Modulation of heart rate and heart rate variability by n-3 long chain polyunsaturated fatty acids: Speculation on mechanism(s)

Heart rate (HR) and heart rate variability (HRV) are valuable markers of health. Although the underlying mechanism(s) are controversial, it is well documented that n-3 long chain polyunsaturated fatty acid (LCPUFA) intake improves HR and HRV in various populations. Autonomic modulation and/or alterations in cardiac electrophysiology are commonly cited as potential mechanisms responsible for these effects. This article reviews existing evidence for each and explores a separate mechanism which has not received much attention but has scientific merit. Based on presented evidence, it is proposed that n-3 LCPUFAs affect HR and HRV directly by autonomic modulation and indirectly by altering circulating factors, both dependently and independently of the autonomic nervous system. The evidence for changes in cardiac electrophysiology as the mechanism by which n-3 LCPUFAs affect HR and HRV needs strengthening.

Prenatal DHA supplementation and infant attention

BACKGROUND

Results of randomized trials on the effects of prenatal docosahexaenoic acid (DHA) on infant cognition are mixed, but most trials have used global standardized outcomes, which may not be sensitive to effects of DHA on specific cognitive domains.

METHODS

Women were randomized to 600 mg/d DHA or a placebo for the last two trimesters of pregnancy. Infants of these mothers were then followed on tests of visual habituation at 4, 6, and 9 mo of age.

RESULTS

DHA supplementation did not affect look duration or habituation parameters but infants of supplemented mothers maintained high levels of sustained attention (SA) across the first year; SA declined for the placebo group. The supplemented group also showed significantly reduced attrition on habituation tasks, especially at 6 and 9 mo.

CONCLUSION

The findings support with the suggestion that prenatal DHA may positively affect infants' attention and regulation of state.

Long-chain omega-3 fatty acids and optimization of cognitive performance

Low consumption of the omega-3 fatty acids, eicosapentaenoic and docosahexaenonic acids, is linked to delayed brain development and, in late life, increased risk for Alzheimer's disease. The current review focuses on cognitive functioning during midlife and summarizes available scientific evidence relevant to the hypothesis that adequate dietary consumption of the long-chain omega-3 fatty acids is necessary for optimal cognitive performance. Taken together, the findings suggest that raising the currently low consumption among healthy adults may improve some aspects of cognitive performance. Nonetheless, evidence from randomized clinical trials is comparatively sparse and leaves unclear: (a) whether such effects are clinically significant, (b) whether effects of eicosapentaenoic acid and DHA differ, (c) which dimensions of cognitive function are affected, (d) the dose-response relationships, or (e) the time course of the response. Clarification of these issues through both laboratory and clinical investigations is a priority given the broad implications for public health, as well as for military personnel and other positions of high performance demand and responsibility.

Pregnant Women in Louisiana Are Not Meeting Dietary Seafood Recommendations

Background. The 2015-2020 Dietary Guidelines for Americans recommend that pregnant women and women of childbearing ages consume 8-12 oz. of seafood per week. Fish are the major dietary source of omega-3 long chain polyunsaturated fatty acids, which have benefits for the mother and fetus. Methods. In this observational study, we investigated dietary habits of pregnant women in Baton Rouge, Louisiana, USA, to determine if they achieve recommended seafood intake. A print survey, which included commonly consumed foods from protein sources (beef, chicken, pork, and fish), was completed by pregnant women at a single-day hospital convention for expecting families in October 2015. Women (n = 221) chose from six predefined responses to answer how frequently they were consuming each food. Results. Chicken was consumed most frequently (75% of women), followed by beef (71%), pork (65%), and fish (22%), respectively. Consumption frequency for the most consumed fish (catfish, once per month) was similar to or lower than that of the least consumed beef, chicken, and pork foods. Consumption frequency for the most consumed chicken and beef foods was at least once per week. Conclusion. Our data indicate that pregnant women in Louisiana often consume protein sources other than fish and likely fail to meet dietary seafood recommendations.

Modification of Docosahexaenoic Acid Composition of Milk from Nursing Women Who Received Alpha Linolenic Acid from Chia Oil during Gestation and Nursing

α-Linolenic acid (ALA) is the precursor of docosahexaenoic acid (DHA) in humans, which is fundamental for brain and visual function. Western diet provides low ALA and DHA, which is reflected in low DHA in maternal milk. Chia oil extracted from chia (Salvia hispanica L.), a plant native to some Latin American countries, is high in ALA (up to 60%) and thereby is an alternative to provide ALA with the aim to reduce DHA deficits. We evaluated the modification of the fatty acid profile of milk obtained from Chilean mothers who received chia oil during gestation and nursing. Forty healthy pregnant women (22–35 years old) tabulated for food consumption, were randomly separated into two groups: a control group with normal feeding (n = 21) and a chia group (n = 19), which received 16 mL chia oil daily from the third trimester of pregnancy until the first six months of nursing. The fatty acid profile of erythrocyte phospholipids, measured at six months of pregnancy, at time of delivery and at six months of nursing, and the fatty acid profile of the milk collected during the first six months of nursing were assessed by gas-chromatography. The chia group, compared to the control group, showed (i) a significant increase in ALA ingestion and a significant reduction of linoleic acid (LA) ingestion, no showing modification of arachidonic acid (AA), eicosapentaenoic acid (EPA) and DHA; (ii) a significant increase of erythrocyte ALA and EPA and a reduction of LA. AA and DHA were not modified; (iii) a increased milk content of ALA during the six months of nursing, whereas LA showed a decrease. AA and EPA were not modified, however DHA increased only during the first three months of nursing. Consumption of chia oil during the last trimester of pregnancy and the first three months of nursing transiently increases the milk content of DHA.

Synthesis of long-chain fatty acid derivatives as a novel anti-Alzheimer's agent

In order to develop new drugs for Alzheimer's disease, we prepared 17 fatty acid derivatives with different chain lengths and different numbers and positions of double bonds by using Wittig reaction and stereospecific hydrogenation of triple bonds as key reactions. Among them, (4Z,15Z)-octadecadienoic acid (10) and (23Z,34Z)-heptatriacontadienoic acid (16) showed the most potent neurite outgrowth activities on Aβ(25-35)-treated rat cortical neurons, which activities were comparable to that of a positive control, NGF. Both fatty acids 10 and 16 possess two (Z)-double bonds at the n-3 and n-14 positions, which might be important for the neurite outgrowth activity.

Fish oil-supplementation from 9 to 12 months of age affects infant attention in a free-play test and is related to change in blood pressure

INTRODUCTION

This intervention examined whether fish-oil-supplementation in late infancy modifies free-play test scores and if this is related to blood pressure (BP) and mean RR interval.

PATIENTS AND METHODS

83 Danish 9-month-old infants were randomized to ±fish oil (FO) (3.4±1.1mL/d) for 3months and 61 of these completed the free-play-test before and after the intervention.

RESULTS

Most of the free-play scores changed during the intervention, but the intervention affected only the number of looks away from the toy, which was increased in +FO and decreased in -FO (p=0.037). The increased numbers of looks away were associated with an increase in erythrocyte eicosapentaenoic acid (r=0.401, p=0.017, n=35) and were also associated with a decrease in systolic-BP (r=-0.511, p<0.001, n=52).

CONCLUSIONS

The results indicate that n-3 fatty acid intake also in late infancy can influence brain development and that the cognitive and cardiovascular effects may be related.

Effects of docosahexaenoic acid supplementation during pregnancy on fetal heart rate and variability: a randomized clinical trial

DHA (22:6n-3) supplementation during infancy has been associated with lower heart rate (HR) and improved neurobehavioral outcomes. We hypothesized that maternal DHA supplementation would improve fetal cardiac autonomic control and newborn neurobehavior. Pregnant women were randomized to 600 mg/day of DHA or placebo oil capsules at 14.4 (+/-4) weeks gestation. Fetal HR and HRV were calculated from magnetocardiograms (MCGs) at 24, 32 and 36 weeks gestational age (GA). Newborn neurobehavior was assessed using the Neonatal Behavioral Assessment Scale (NBAS). Post-partum maternal and infant red blood cell (RBC) DHA was significantly higher in the supplemented group as were metrics of fetal HRV and newborn neurobehavior in the autonomic and motor clusters. Higher HRV is associated with more responsive and flexible autonomic nervous system (ANS). Coupled with findings of improved autonomic and motor behavior, these data suggest that maternal DHA supplementation during pregnancy may impart an adaptive advantage to the fetus.

Fetal cardiac autonomic control during breathing and non-breathing epochs: the effect of maternal exercise

We explored whether maternal exercise during pregnancy moderates the effect of fetal breathing movements on fetal cardiac autonomic control assessed by metrics of heart rate (HR) and heart rate variability (HRV). Thirty women were assigned to Exercise or Control group (n=15/group) based on the modifiable physical activity questionnaire (MPAQ). Magnetocardiograms (MCG) were recorded using a dedicated fetal biomagnetometer. Periods of fetal breathing activity and apnea were identified using the fetal diaphragmatic magnetomyogram (dMMG) as a marker. MCG R-waves were marked. Metrics of fetal HR and HRV were compared using 1 breathing and 1 apneic epoch/fetus. The main effects of group (Exercise vs. Control) and condition (Apnea vs. Breathing) and their interactions were explored. Fetal breathing resulted in significantly lower fetal HR and higher vagally-mediated HRV. Maternal exercise resulted in significantly lower fetal HR, higher total HRV and vagally-mediated HRV with no difference in frequency band ratios. Significant interactions between maternal exercise and fetal breathing were found for metrics summarizing total HRV and a parasympathetic metric. Post hoc comparison showed no group difference during fetal apnea. Fetal breathing was associated with a loss of Total HRV in the Control group and no difference in the Exercise group. Both groups show enhanced vagal function during fetal breathing; greater in the Exercise group. During in utero breathing movements, the fetus of the exercising mother has enhanced cardiac autonomic function that may give the offspring an adaptive advantage.

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

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

Maternal fatty acid status during pregnancy and lactation and relation to newborn and infant status

The present review of determinants of infant fatty acid status was undertaken as part of a conference on 'Fatty acid status in early life in low-income countries: determinants and consequences'. Emphasis is placed on the essential fatty acids, and particularly the physiologically important long chain polyunsaturated fatty acids (LCPUFAs) of 20 and 22 carbons. We are unaware of any studies of determinants of infant fatty acid status in populations with a cultural dietary pattern with low amounts of linoleic acid (LA, 18:2n-6) and α-linolenic acid (ALA,18:3n-3). Many reports suggest that there may be adverse health effects related to the increased proportion of LA in relation to ALA, which have occurred worldwide due to the increased availability of vegetable oils high in LA. The issue of dietary n-6 to n-3 balance may apply to infant fatty acid status both during fetal and post-natal life; however, this review focuses on the n-3 and n-6 LCPUFA, in particular, docosahexaenoic acid (DHA, 22:6n-3) and arachidonic acid (AA, 20:4n-6), which are the predominant n-3 and n-6 LCPUFA found in cell membranes. The evidence that these fatty acids are preferentially transferred from maternal to fetal circulation across the placenta, and the sources and mechanisms for this transfer, are reviewed. We also address the sources of DHA and AA for the newborn including human milk DHA and AA and the factors that influence maternal DHA status and consequently the amount of DHA available for transfer to the fetus and infant via human milk.