Omega-3 fatty acid deficiency in major depressive disorder is caused by the interaction between diet and a genetically determined abnormality in phospholipid metabolism

Trim the fat: the role of omega-3 fatty acids in psychopharmacology

The American Psychiatric Association (APA) currently recommends the use of omega-3 fatty acid supplementation for depressive disorders, impulse-control disorders, and psychotic disorders in treatment guidelines. This review examines the evidence for efficacy of omega-3 fatty acids in depressive disorders, bipolar disorder, anxiety disorders, post-traumatic stress disorder (PTSD), and psychosis. Meta-analysis of randomized-controlled trials of omega-3 fatty acids for depression are inconclusive, with strong evidence of publication bias, sizable heterogeneity between included studies, and substantial methodological shortcomings in included trials. The large amount of heterogeneity in findings of RCTs of omega-3 fatty acids for unipolar depression is likely attributable to highly heterogeneous sample populations that are given different omega-3 supplements [which differ widely in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) content, ratio, and dosage] as either adjunctive or monotherapy of other existing treatments, and then measure several different outcomes of depression symptomatology with likely incomplete blinding. Evidence of efficacy of omega-3 supplementation in treating psychosis, PTSD, anxiety, and bipolar mania is minimal. The current guidelines recommending the use of omega-3 fatty acids in adulthood psychiatric conditions should be revisited, especially given several recent negative studies examining the effects of omega-3 fatty acids for cardiovascular disease. Recommending likely ineffective treatment to patients, no matter how benign the side-effect profile, has opportunity cost (e.g. other more effective medications or therapies not being utilized) and likely affects patient compliance with other evidence-based treatments.

Brain Fatty Acid Composition and Inflammation in Mice Fed with High-Carbohydrate Diet or High-Fat Diet

Both high fat diet (HFD) and high carbohydrate diet (HCD) modulate brain fatty acids (FA) composition. Notwithstanding, there is a lack of information on time sequence of brain FA deposition either for HFD or HCD. The changes in brain FA composition in mice fed with HFD or HCD for 7, 14, 28, or 56 days were compared with results of 0 (before starting given the diets). mRNA expressions of allograft inflammatory factor 1 (Aif1), cyclooxygenase-2 (Cox 2), F4/80, inducible nitric oxide synthase (iNOS), integrin subunit alpha m (Itgam), interleukin IL-1β (IL-1β), IL-6, IL-10, and tumor necrosis factor alpha (TNF-α) were measured. The HFD group had higher speed of deposition of saturated FA (SFA), monounsaturated FA (MUFA), and polyunsaturated FA (PUFA) at the beginning of the experimental period. However, on day 56, the total amount of SFA, MUFA, and PUFA were similar. mRNA expressions of F4/80 and Itgam, markers of microglia infiltration, were increased (p < 0.05) in the brain of the HCD group whereas inflammatory marker index (IMI) was higher (46%) in HFD group. In conclusion, the proportion of fat and carbohydrates in the diet modulates the speed deposition of FA and expression of inflammatory gene markers.

The importance of n-6/n-3 fatty acids ratio in the major depressive disorder

This review aims to clarify the relation between the ratio of omega-6 to omega-3 fatty acids and the development of depression. It is explained how these fatty acids are involved in the production of eicosanoids and how these fatty acids can affect the membrane fluidity, by their incorporation into membrane phospholipids. In addition, it is described how omega-3 derivatives are shown to regulate gene transcription. In view of the pathophysiology of depression, the mechanisms of how an altered ratio of omega-6 to omega-3 could be involved in depression are discussed. Possible mechanisms could include an increased production of pro-inflammatory cytokines, which can activate the HPA axis and a changed membrane fluidity, which potentially affects membrane bound enzymes, ion channels, receptor activity and neurotransmitter binding. In view of clinical trials, it is also discussed whether omega-3 supplementation could have a beneficial effect in the treatment of depressive patient. There are strong indications that an increased ratio of membrane omega-6 to omega-3 is involved in the pathogenesis of depression and so far, omega-3 supplementation has shown positive effects in clinical trials.

Application of fatty acid and lipid measurements in neuropsychiatry

The importance of lipids in the understanding of disease states is constantly increasing. Whilst the link between metabolic disorders and lipids seems to be clear, interpreting lipid regulation in the context of neuropsychiatric disorders is a new approach. Mental disorders account for almost 15% of the total global disease burden with Alzheimer’s disease, depression or schizophrenia being amongst the most widespread mental disorders in the general population. For this reason rapid and early diagnosis is crucial and finding the right biomarkers is of great importance. Lipids appear to be essential in learning the aetiopathology of neuropsychiatric diseases as well as in biomarker research as they are most abundantly present in the brain. This study discusses recent findings in neuropsychiatry in the context of lipid analysis.

A review of recent evidence in human studies of n-3 and n-6 PUFA intake on cardiovascular disease, cancer, and depressive disorders: does the ratio really matter?

Polyunsaturated fatty acids (PUFAs) have been considered of great interest for human health due to their potential anti-inflammatory action that may protect from a number of chronic-degenerative diseases with an inflammatory pathogenesis. This review aimed to report the most updated evidence of both n-3 and n-6 PUFAs effect on cardiovascular disease, cancer, and depression in humans. Attention has been also paid to those studies exploring the effects of the ratio intake. Results from pooled analyses of human studies reported a general positive effect of n-3 PUFAs intake on all outcomes considered. In contrast, the role of n-6 PUFAs on human health needs to be better assessed in order to clearly identify which compound exerts beneficial/harmful effects. Only a limited number of clinical studies considered the n-3:n-6 PUFAs ratio, rather reporting contrasting results. A number of limitations when considering the ratio between these two families of PUFAs have risen.

Lack of Dietary Polyunsaturated Fatty Acids Causes Synapse Dysfunction in the Drosophila Visual System

Polyunsaturated fatty acids (PUFAs) are essential nutrients for animals and necessary for the normal functioning of the nervous system. A lack of PUFAs can result from the consumption of a deficient diet or genetic factors, which impact PUFA uptake and metabolism. Both can cause synaptic dysfunction, which is associated with numerous disorders. However, there is a knowledge gap linking these neuronal dysfunctions and their underlying molecular mechanisms. Because of its genetic manipulability and its easy, fast, and cheap breeding, Drosophila melanogaster has emerged as an excellent model organism for genetic screens, helping to identify the genetic bases of such events. As a first step towards the understanding of PUFA implications in Drosophila synaptic physiology we designed a breeding medium containing only very low amounts of PUFAs. We then used the fly’s visual system, a well-established model for studying signal transmission and neurological disorders, to measure the effects of a PUFA deficiency on synaptic function. Using both visual performance and eye electrophysiology, we found that PUFA deficiency strongly affected synaptic transmission in the fly’s visual system. These defects were rescued by diets containing omega-3 or omega-6 PUFAs alone or in combination. In summary, manipulating PUFA contents in the fly’s diet was powerful to investigate the role of these nutrients on the fly´s visual synaptic function. This study aims at showing how the first visual synapse of Drosophila can serve as a simple model to study the effects of PUFAs on synapse function. A similar approach could be further used to screen for genetic factors underlying the molecular mechanisms of synaptic dysfunctions associated with altered PUFA levels.

Transcriptomic analysis of the effects of a fish oil enriched diet on murine brains

The health benefits of fish oil enriched with high omega-3 polyunsaturated fatty acids (n-3 PUFA) are widely documented. Fish oil as dietary supplements, however, show moderate clinical efficacy, highlighting an immediate scope of systematic in vitro feedback. Our transcriptomic study was designed to investigate the genomic shift of murine brains fed on fish oil enriched diets. A customized fish oil enriched diet (FD) and standard lab diet (SD) were separately administered to two randomly chosen populations of C57BL/6J mice from their weaning age until late adolescence. Statistical analysis mined 1,142 genes of interest (GOI) differentially altered in the hemibrains collected from the FD- and SD-fed mice at the age of five months. The majority of identified GOI (∼40%) encodes proteins located in the plasma membrane, suggesting that fish oil primarily facilitated the membrane-oriented biofunctions. FD potentially augmented the nervous system's development and functions by selectively stimulating the Src-mediated calcium-induced growth cascade and the downstream PI3K-AKT-PKC pathways. FD reduced the amyloidal burden, attenuated oxidative stress, and assisted in somatostatin activation—the signatures of attenuation of Alzheimer's disease, Parkinson's disease, and affective disorder. FD induced elevation of FKBP5 and suppression of BDNF, which are often linked with the improvement of anxiety disorder, depression, and post-traumatic stress disorder. Hence we anticipate efficacy of FD in treating illnesses such as depression that are typically triggered by the hypoactivities of dopaminergic, adrenergic, cholinergic, and GABAergic networks. Contrastingly, FD's efficacy could be compromised in treating illnesses such as bipolar disorder and schizophrenia, which are triggered by hyperactivities of the same set of neuromodulators. A more comprehensive investigation is recommended to elucidate the implications of fish oil on disease pathomechanisms, and the result-driven repositioning of fish oil utilization may revitalize its therapeutic efficacy.

Relationship between central and peripheral fatty acids in humans

Background

In recent years the physiological and pathological importance of fatty acids in both the periphery and central nervous system (CNS) has become increasingly apparent. However surprisingly limited research has been conducted comparing the fatty acid composition of central and peripheral lipid stores.

Methods

The present study compared the distribution of polyunsaturated (PUFA), as well as specific saturated (SFA) and monounsaturated (MUFA) fatty acids in the whole blood and cerebrospinal fluid (CSF) of humans. Gas chromatography with flame ionization detection was used to determine the fatty acid profiles of twenty-eight matched CSF and whole blood samples. Multiple linear regression modeling, controlling for age, was used to identify significant relationships.

Results

A significant positive relationship was seen between whole blood total omega-3 fatty acids and the CSF omega-3 subfractions, docosapentaenoic acid (DPA) (P = 0.019) and docosahexaenoic acid (DHA) (P = 0.015). A direct association was also observed between the whole blood and CSF omega-6 PUFA, arachidonic acid (AA) (P = 0.045). Interestingly an inverse association between central and peripheral oleic acid was also found (P = 0.045).

Conclusions

These findings indicate a relationship between central and peripheral fatty acids of varying degrees of unsaturation and chain length and support the view that some systemic fatty acids are likely to cross the human blood brain barrier (BBB) and thereby influence central fatty acid concentrations.

Omega-3 fatty acids for the treatment of depression: systematic review and meta-analysis

We conducted a meta-analysis of randomized, placebo-controlled trials of omega-3 fatty acid (FA) treatment of major depressive disorder (MDD) in order to determine efficacy and to examine sources of heterogeneity between trials. PubMed (1965-May 2010) was searched for randomized, placebo-controlled trials of omega-3 FAs for MDD. Our primary outcome measure was standardized mean difference in a clinical measure of depression severity. In stratified meta-analysis, we examined the effects of trial duration, trial methodological quality, baseline depression severity, diagnostic indication, dose of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in omega-3 preparations, and whether omega-3 FA was given as monotherapy or augmentation. In 13 randomized, placebo-controlled trials examining the efficacy of omega-3 FAs involving 731 participants, meta-analysis demonstrated no significant benefit of omega-3 FA treatment compared with placebo (standard mean difference (SMD)=0.11, 95% confidence interval (CI): -0.04, 0.26). Meta-analysis demonstrated significant heterogeneity and publication bias. Nearly all evidence of omega-3 benefit was removed after adjusting for publication bias using the trim-and-fill method (SMD=0.01, 95% CI: -0.13, 0.15). Secondary analyses suggested a trend toward increased efficacy of omega-3 FAs in trials of lower methodological quality, trials of shorter duration, trials which utilized completers rather than intention-to-treat analysis, and trials in which study participants had greater baseline depression severity. Current published trials suggest a small, non-significant benefit of omega-3 FAs for major depression. Nearly all of the treatment efficacy observed in the published literature may be attributable to publication bias.

Erythrocyte n-3 polyunsaturated fatty acid and seafood intake decrease the risk of depression: case-control study in Korea

BACKGROUND/AIMS

Low intake or tissue levels of n-3 polyunsaturated fatty acids (PUFA) have been associated with an increased risk of depression, but some studies do not support the association. The purpose of the present study was to evaluate the hypothesis that erythrocyte levels of n-3 PUFA and intake of seafood are negatively associated with the risk of depression in Koreans.

METHODS

We investigated 80 patients diagnosed with a score ≥25 on the Center for Epidemiological Studies Depression Scale, Korean version, and confirmed by a psychiatrist. Eighty-eight controls without a chronic disease were matched to the cases for age and sex.

RESULTS

Multivariate-adjusted regression analysis showed that the risk of depression was significantly and negatively associated with erythrocyte levels of 20:5 n-3, 22:6 n-3, 16:0 and 18:0, but positively associated with erythrocyte levels of 18:2t and 16:1 after adjusting for confounding factors. In addition, the risk of depression was negatively associated with the intake of energy, carbohydrate, seafood and grains, but positively with the intake of fat and meat after adjustment for confounding factors.

CONCLUSIONS

The risk of depression could be decreased with increased erythrocyte levels of n-3 PUFA and saturated fatty acids, as well as seafood intake, but decreased erythrocyte levels of trans fatty acids in Koreans.

High-fat diet transition reduces brain DHA levels associated with altered brain plasticity and behaviour

To assess how the shift from a healthy diet rich in omega-3 fatty acids to a diet rich in saturated fatty acid affects the substrates for brain plasticity and function, we used pregnant rats fed with omega-3 supplemented diet from their 2nd day of gestation period as well as their male pups for 12 weeks. Afterwards, the animals were randomly assigned to either a group fed on the same diet or a group fed on a high-fat diet (HFD) rich in saturated fats for 3 weeks. We found that the HFD increased vulnerability for anxiety-like behavior, and that these modifications harmonized with changes in the anxiety-related NPY1 receptor and the reduced levels of BDNF, and its signalling receptor pTrkB, as well as the CREB protein. Brain DHA contents were significantly associated with the levels of anxiety-like behavior in these rats.

Associations between omega-3 poly-unsaturated fatty acids from fish consumption and severity of depressive symptoms: an analysis of the 2005-2008 National Health and Nutrition Examination Survey

Fish is the primary source of dietary omega-3 poly-unsaturated fatty acids EPA and DHA, which have been reported to reduce depressive symptoms in clinical trials. We assessed the association between fish consumption and depressive symptoms in a nationally representative sample of 10,480 adults from the 2005-2008 National Health and Nutrition Examination Survey. Depressive symptoms were classified by severity using the Patient Health Questionnaire. Fish meal consumption reported in 30-day food frequency questionnaires, and EPA+DHA intake computed from 24-h dietary recalls were evaluated in relation to depressive symptoms using multivariable ordinal logistic regression. Consumption of breaded fish showed an increased risk of greater depressive symptom severity, while all fish, non-breaded fish, and shell fish were not associated. Any EPA+DHA intake was significantly associated with fewer depressive symptoms. Exposure-response analyses revealed no clear patterns for any intake measures. Inconsistent patterns of associations in our study may be partially explained by exposure misclassification.

Essential fatty acids and psychiatric disorders

Psychiatric disorders are a significant source of disability worldwide. Increasing evidence indicates that disturbances of fatty acids and phospholipid metabolism can play a part in a wide range of psychiatric, neurological, and developmental disorders in adults. Essential fatty acids, ω-3 and ω-6 polyunsaturated fatty acids, play a central role in the normal development and functioning of the brain and central nervous system. The aim of this article is to discuss the overall insight into roles of essential fatty acids in the development of mental disorders (depression, schizophrenia, bipolar disorder) and, in light of the fact that disturbances of fatty acid metabolism can play a part in the above-mentioned disorders, to investigate the current knowledge of lipid abnormalities in posttraumatic stress disorder. The information in this review was obtained after extensive MEDLINE searching of each topic area through relevant published studies from the past 20 years. References from the obtained studies were also used. This review summarizes the knowledge in terms of essential fatty acids intake and metabolism, as well as evidence pointing to potential mechanisms of essential fatty acids in normal brain functioning and development of neuropsychiatric disorders. The literature shows that ω-3 fatty acids provide numerous health benefits and that changes in their concentration in organisms are connected to a variety of psychiatric symptoms and disorders, including stress, anxiety, cognitive impairment, mood disorders, and schizophrenia. Further studies are necessary to confirm ω-3 fatty acids' supplementation as a potential rational treatment in psychiatric disorders.

Fatty acids intake and depressive symptomatology in a Greek sample: an epidemiological analysis

BACKGROUND

Depression is associated with an increased risk of cardiovascular disease, but the association with dietary habits is not well understood. The aim of this work was to statistically model the association of depressive symptoms with fatty acids intake in persons free of cardiovascular disease.

METHOD

A random multistage sampling, stratified by gender and age, was performed during 2001-2002. In the present work, psychological and dietary data from 453 men (19-89 years) and 400 women (18-84 years) were analyzed. Depression was assessed with the Zung's Self-rating Depression Scale (ZDRS). After a validation for the investigated population, plasma fatty acids in the form of their methyl esters were determined by gas chromatography, while dietary fatty acids were determined through a semiquantitative food frequency questionnaire and local food composition tables.

RESULTS

Women had significantly higher scores on the ZDRS as compared with men (47 ± 9 vs. 43 ± 10, p < 0.001). Multiadjusted data analysis after adjusting for age, gender, lifestyle, and dietary habits revealed that increased polyunsaturated fatty acid (PUFA) and monounsaturated fatty acid (MUFA) concentrations, and, more specifically, high concentrations of plasma total n-3 fatty acids (b ± SE: -1.9 ± 0.5, p  =  0.03), docosahexaenoic acid (-2.91 ± 1.04, p  =  0.02), eicosapentaenoic acid (-2.54 ± 0.84, p  =  0.03), α-linoleic acid (-16.8 ± 7.3, p  =  0.01), and linoleic acid (-3.97 ± 0.21, p  =  0.03), were associated with lower scores in the depression scale used.

CONCLUSION

These results indicate that increased PUFA and MUFA concentrations are associated with diminished depressive symptomatology among apparently healthy adults.

The role of 5-HT₁A receptors in fish oil-mediated increased BDNF expression in the rat hippocampus and cortex: a possible antidepressant mechanism

Epidemiological and dietary studies show that nutritional deficit of omega-3 polyunsaturated fatty acids (ω-3 PUFA) is directly related to the prevalence and severity of depression. Supplementation with docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) during critical periods of development (pregnancy and lactation) is essential for cortical maturation, synaptogenesis and myelination, and may also mitigate the risk for cognitive deficits and psychopathologies in young adults. The present study was performed to evaluate the involvement of serotonin (5-HT) receptors, particularly of 5-HT(1A), and hippocampal brain-derived neurotrophic factor (BDNF) expression in the antidepressant effect of ω-3 PUFA supplementation. In Experiment 1, the antidepressant effects of fish oil were assessed by the modified forced swim test in adult rats. The data indicated a robust antidepressant effect produced by this supplementation and that treatment of the rats with WAY 100135 reversed this effect. In Experiment 2, cortical and hippocampal contents of BDNF, 5-HT, dopamine (DA) and its metabolites, 5-hydroxyindoleacetic acid (5-HIAA), and 3,4-dihydroxyphenylacetic acid (DOPAC), were determined in animals subjected to the same protocol. Increased BDNF expression in the cortex and hippocampus of both age groups was detected. In 90 day-old rats, 5-HT content in the hippocampus was increased, whereas 5-HIAA formation was diminished in the fish oil group. We suggest the occurrence of a reciprocal involvement of 5-HT(1A) receptors activation and the hippocampal BDNF-increased expression mediated by fish oil supplementation. These data corroborate and expand the notion that supplementation with ω-3 PUFA produces antidepressant effects mediated by an increase in serotonergic neurotransmission, particularly in the hippocampus. This article is part of a Special Issue entitled 'Anxiety and Depression'.

Increased breath ethane levels in medicated patients with schizophrenia and bipolar disorder are unrelated to erythrocyte omega-3 fatty acid abundance

Oxidative stress has been reported to be elevated in mental illness. Preliminary evidence suggests this phenomenon can be assessed non-invasively by determining breath levels of the omega-3 polyunsaturated fatty acid (PUFA) oxidation product ethane. This study compares alkane levels in chronic, medicated, patients with schizophrenia or bipolar disorder with those in healthy controls. Both ethane and butane levels were significantly increased in patients with schizophrenia or bipolar disorder, although elevated butane levels were likely due to increased ambient gas concentrations. Ethane levels were not correlated with symptom severity or with erythrocyte omega-3 PUFA levels. Our results support the hypothesis that oxidative stress is elevated in patients with schizophrenia and bipolar disorder leading to increased breath ethane abundance. This does not appear to be caused by increased abundance of omega-3 PUFA, but rather is likely due to enhanced oxidative damage of these lipids. As such, breath hydrocarbon analysis may represent a simple, non-invasive means to monitor the metabolic processes occurring in these disorders.

N-3 (omega-3) Fatty acids in postpartum depression: implications for prevention and treatment

A growing body of clinical and epidemiological evidence suggests that low dietary intake and/or tissue levels of n-3 (omega-3) polyunsaturated fatty acids (PUFAs) are associated with postpartum depression. Low tissue levels of n-3 PUFAs, particularly docosahexaenoic acid (DHA), are reported in patients with either postpartum or nonpuerperal depression. Moreover, the physiological demands of pregnancy and lactation put childbearing women at particular risk of experiencing a loss of DHA from tissues including the brain, especially in individuals with inadequate dietary n-3 PUFA intake or suboptimal metabolic capabilities. Animal studies indicate that decreased brain DHA in postpartum females leads to several depression-associated neurobiological changes including decreased hippocampal brain-derived neurotrophic factor and augmented hypothalamic-pituitary-adrenal responses to stress. Taken together, these findings support a role for decreased brain n-3 PUFAs in the multifactorial etiology of depression, particularly postpartum depression. These findings, and their implications for research and clinical practice, are discussed.

Lowered omega-3 PUFAs are related to major depression, but not to somatization syndrome

BACKGROUND

Studies indicated a depletion of omega-3 fatty acid levels and an imbalance between omega-3 and omega-6 PUFAs in depressive patients. Depletion of omega-3 PUFAs may be related to the immune and serotonergic pathophysiologies of depression by alterations in membrane fluidity and modulation of membrane receptors, enzyme activities and carriers. Previous studies also found serotonergic and immunological disturbances in subjects with somatoform symptoms. Based on these findings we aimed to investigate PUFA concentrations and its relations to other biological systems in depressed patients and in patients with somatoform symptoms.

METHODS

We examined 150 subjects divided in 4 groups, i.e. somatization syndrome; depression; depression and somatization syndrome; controls. Blood samples were analyzed for fatty acids, markers of the serotonergic system and the immune system.

RESULTS

The study was able to replicate earlier findings in patients with depression (lowered omega-3 PUFAs, increased omega-6/omega-3 ratios in serum cholesteryl esters). The somatization syndrome group showed no abnormalities in the mentioned fatty acid levels. Only depressive patients revealed associations between fatty acids with serotonergic and immunological markers.

LIMITATIONS

We used current state diagnoses, and the consideration of lifetime diagnoses and longitudinal studies could highlight further aspects of the reported results.

CONCLUSIONS

The findings are further confirming that the concepts of depression and somatoform disorders should not be merged indiscriminately together, even though they often occur together. We conclude that in depression and somatoform syndrome different biological mechanisms seem to be involved.

Omega-3 polyunsaturated fatty acids and anxiety disorders

Anxiety disorders are a common group of psychiatric illnesses which have significant personal, family and societal costs. Current treatments have limited efficacy in many patients highlighting a need for new therapeutic approaches to be explored. Anxiety disorders exhibit marked comorbity with mood disorders suggesting the existence of mechanistic similarities. Such a notion is supported by observations that some conventional pharmacotherapies are both effective antidepressants and anxiolytics. As such, given that omega-3 PUFA supplementation may be effective in the treatment of major depressive disorder it is reasonable to propose that they may also possess anxiolytic properties. Experimental data in support of such a hypothesis is currently lacking although reduced abundance of omega-3 PUFA have been reported in patients with anxiety, while supplementation with omega-3 PUFA appears to inhibit activation of the HPA axis and can ameliorate some of the symptoms of anxiety. Clinical investigations carried out to date have, however, involved small numbers of participants. Larger trials using a variety of omega-3 PUFA species in clinically well-defined patients with anxiety will be required to demonstrate a therapeutic role for omega-3 PUFA in these disorders. Given the excellent side effect profile of omega-3 PUFA as well as their strong theoretical rationale, such future trials appear justified.

Validation of an FFQ for evaluation of EPA and DHA intake

Objective

To validate an FFQ for the assessment of dietary EPA and DHA against their relative concentrations in red blood cells (RBC).

Design

Cross-sectional analysis of baseline data. Intakes of marine food products and EPA and DHA were estimated by FFQ on the basis of consumption of marine food products in the last month. Fatty acid composition of RBC membranes was quantified by GC.

Setting

Saint-François d’Assise Hospital, Québec, Canada.

Subjects

A total of sixty-five middle-aged women who participated in a randomized clinical trial.

Results

Spearman’s correlation coefficient between intake of EPA, DHA and EPA + DHA and their corresponding concentration in RBC was 0·46, 0·40 and 0·42, respectively (allP< 0·05). Multiple regression analysis of EPA+DHA intake and RBC EPA + DHA concentration indicated positive and significant correlations for oily fish (β= 0·44, 95 % CI 0·16, 0·72,P= 0·0027), total fish (β= 0·42, 95 % CI 0·19, 0·64,P= 0·0005) and marine food products (β= 0·42, 95 % CI 0·20, 0·64,P= 0·0003). No other marine food products significantly predicted RBC EPA + DHA concentration.

Conclusions

Although the present validation study was undertaken among middle-aged women with low consumption of marine food products (<3 servings/week), our FFQ provided estimates of EPA and DHA intakes that correlated fairly well with their RBC concentrations. However, the absence of correlations between EPA + DHA intakes from different marine species suggests that a minimum EPA + DHA intake is necessary to observe a relationship with RBC EPA + DHA concentrations.

Dietary lipids and geriatric depression scale score among elders: the EPIC-Greece cohort

In a prospective epidemiological investigation aiming to identify dietary lipids potentially associated with affective state and depression, 610 healthy men and women aged 60 years or older, participating in the EPIC-Greece cohort and residing in the Attika region had dietary, sociodemographic, anthropometric, medical and lifestyle variables ascertained at enrollment. Six to 13 years later, affective state was evaluated through the 15-point geriatric depression scale (GDS) score along with cognitive function and medical variables. In multivariate linear regression analysis, while adjusting for potential confounders, GDS score was negatively associated with dietary intake of monounsaturated lipids (MUFA) and their main source, olive oil, and positively associated with intake of polyunsaturated lipids (PUFA) and one of their principal sources, seed oils. Intake of calories, total lipids, fish and seafood or saturated lipids did not exhibit significant association with GDS. Potential non-linearities were assessed by quantile multivariate regression analysis: The median GDS score was positively associated with PUFA and seed oils intake, while other lipid groups showed no appreciable associations. The 90th percentile of the GDS score (towards the high end) exhibited significant negative associations with MUFA and olive oil, weaker positive associations with PUFA and seed oils and no appreciable association with other lipid group dietary intakes. We conclude that among Attika elders, lower intake of seed oils and higher intake of olive oil prospectively predict a healthier affective state. Olive oil intake, in particular, predicts a lower chance of scoring in the highest part of the GDS.

Omega-3 deficiency associated with perinatal depression: case control study

Women are depleted of omega-3 polyunsaturated fatty acids (n-3 PUFAs) during the perinatal period due to fetal diversion. An association has been shown between lowered n-3 PUFAs and depression in general. We therefore hypothesise that women with lower n-3 PUFA levels are at greater risk of depression during pregnancy. Sixteen depressed and 22 non-depressed women were recruited during the third trimester and fasting bloods were taken for plasma fatty acid analysis. High docosahexaenoic acid (DHA), high total n-3 and a low n-6:n-3 ratio were associated with significantly lower odds of depression. After adjustment for parity, age and education level, those with high DHA still had significantly lower odds of being depressed. Those with high total n-3 and a low n-6:n-3 ratio were also at significantly reduced risk of depression, although the magnitude of the difference was reduced. Study results quantified women with lower omega-3 PUFA levels as being six times more likely to be depressed antenatally, compared to women who had higher omega-3 PUFA levels. The prophylactic benefits of supplementation either prenatally or during pregnancy require close study to assess whether omega-3 PUFAs play a role in the prevention of perinatal depression.

Is there a role for n-3 long-chain polyunsaturated fatty acids in the regulation of mood and behaviour? A review of the evidence to date from epidemiological studies, clinical studies and intervention trials

Selected biochemical evidence suggests a potential role for n-3 long-chain PUFA (n-3PUFA) in the regulation of mood and behaviour. The present paper reviews the relevant evidence, to date, from epidemiological studies, clinical studies and intervention trials. Most evidence is available investigating a role for n-3PUFA in depression, depressive illness and suicidal behaviour, but work is also available on anxiety and anxiety-related disorders, fatigue and fatigue-related disorders, aggression, hostility and anti-social behaviour, inattention, impulsivity and attention deficit hyperactivity disorder and schizophrenic disorders. For all these aspects of mood and behaviour, the evidence available is currently limited and highly inconsistent, both in terms of study methodology and study findings. There is a clear need for further work in this area.

Depression in Parkinson's disease: a double-blind, randomized, placebo-controlled pilot study of omega-3 fatty-acid supplementation

BACKGROUND

Effect of fish oil supplementation in parkinsonian patients with depression measured by Montgomery-Asberg Rating Scale (MADRS), the Clinical Global Impressions Scale (CGI) and Beck Depression Inventory (BECK).

METHOD

Double-blind, placebo-controlled study analyzed depression in 31 patients with Parkinson's Disease and Major Depression (DSM-IV). The patients were double-blind separated in 2 groups that received fish oil (containing omega-3 fatty acids) or mineral oil capsules for 3 months; each group was separated in 2 new groups: one taking antidepressant medication and another one not taking it.

RESULTS

29 patients completed the 12-week trial, 58% were female and the mean age was 64.4 years old. Patients supplemented with fish oil showed a significant decrease in MADRS and CGI-Depression scores, and there was no difference among groups in BDI. 14 patients (42%) met criteria for > or = 50% reduction in MADRS score, 7 patients (22%) met criteria for remission (final MADRS total score < or = 12), and 2 patients (6%) discontinued supplementation of fish oil. HPLC analysis of fatty-acid profile showed increase of omega-3 fatty acid in the erythrocyte membrane of patients taking fish oil.

CONCLUSION

These results reveal that PD patients taking fish oil, with or without antidepressants, presented improvement in depressive symptoms and indicate that the intake of omega-3 can be used with an antidepressant effect or as adjuvant therapy with some other medication. This is a first pilot study with parkinsonian patients and omega-3 supplementation and requires replication in a larger sample.

Article Commentary: The Emerging Role of Eicosapentaenoic Acid as an Important Psychoactive Natural Product: Some Answers but a Lot more Questions

Omega-3 polyunsaturated fatty acids play important roles in both the structure and communication processes of cells. Dietary deficiences of these fatty acids have been implicated in cardiac dysfunction, cancer and mood disorders. In the latter, clinical trials have strongly suggested that not all types of omega-3 PUFA are equally efficacious. In particular eicosapentaenoic acid (EPA) appears to be the most useful in ameliorating the symptoms of major depressive disorder. The mechanism by which omega-3 PUFA have these effects, and why EPA is apparently more effective in this role than the much more abundant brain lipid docosahexaenoic acid, is unclear. The available data do suggest various biologically plausible mechanisms all of which are amenable to study using straightforward experimental approaches. To progress further, a better understanding of how EPA and other omega-3 PUFA effect neurophysiological and neurosignalling processes is required.

Long-chain omega-3 polyunsaturated fatty acids in the blood of children and adolescents with juvenile bipolar disorder

Reduced long-chain omega-3 polyunsaturated fatty acids (LCn-3PUFA), including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have been reported in adult patients suffering from depression and bipolar disorder (BD). LCn-3PUFA status has not previously been examined in children and adolescents with BD compared with healthy controls. Fifteen children and adolescents (9-18 years, M +/- SD = 14.4 +/- 3.48) diagnosed with juvenile bipolar disorder (JBD) and fifteen healthy age and sex-matched controls were assessed for dietary intake and fasting red blood cell (RBC) membrane concentrations of LCn-3PUFA. Fatty acid concentrations were compared between participants diagnosed with JBD and controls after controlling for dietary intake. RBC membrane concentrations of EPA and DHA were not significantly lower in participants diagnosed with JBD compared with healthy controls (M +/- sem EPA = 3.37 +/- 0.26 vs. 3.69 +/- 0.27 microg/mL, P = 0.458; M +/- sem DHA = 22.08 +/- 2.23 vs. 24.61 +/- 2.38 microg/mL, P = 0.528) after controlling for intake. Red blood cell DHA was negatively (r = -0.55; P = 0.044) related to clinician ratings of depression. Although lower RBC concentrations of LCn-3PUFA were explained by lower intakes in the current study, previous evidence has linked reduced LCn-3PUFA to the aetiology of BD. As RBC DHA was also negatively related to symptoms of depression, a randomised placebo-controlled study examining supplementation with LCn-3PUFA as an adjunct to standard pharmacotherapy appears warranted in this patient population.

Collaborative depression care, screening, diagnosis and specificity of depression treatments in the primary care setting

The identification, referral and specific treatment of midlife patients in primary care who are distressed by mood, anxiety, sleep and stress-related symptoms, with or without clinically confirmed menopausal symptoms, are confounded by many structural issues in the delivery of women's healthcare. Diagnosis, care delivery, affordability of treatment, time commitment for treatment, treatment specificity for a particular patient's symptoms and patient receptiveness to diagnosis and treatment all play roles in the successful amelioration of symptoms in this patient population. The value of screening for depression in primary care, the limitations of commonly used screening instruments relative to culture and ethnicity, and which clinical care systems make best use of diagnostic screening programs will be discussed in the context of the midlife woman. The Sequenced Treatment Alternatives to Relieve Depression (STAR*D) program illustrates the relatively high rate of unremitted patients, regardless of clinical setting, who are receiving antidepressants. Nonmedication treatment approaches, referred to in the literature as 'nonsomatic treatments', for depression, anxiety and stress, include different forms of cognitive-behavioral therapy, interpersonal therapy, structured daily activities, mindfulness therapies, relaxation treatment protocols and exercise. The specificity of these treatments, their mechanisms of action, the motivation and time commitment required of patients, and the availability of trained practitioners to deliver them are reviewed. Midlife women with menopausal symptoms and depression/anxiety comorbidity represent a challenging patient population for whom an individualized treatment plan is often necessary. Treatment for depression comorbid with distressing menopausal symptoms would be facilitated by the implementation of a collaborative care program for depression in the primary care setting.

The role of fatty acids in the development and treatment of mood disorders

PURPOSE OF REVIEW

There is increasing evidence from epidemiological, case-control and randomized clinical trials for a link between omega-3 deficiency and the development of mood disorders. This article examines recent evidence for this association.

RECENT FINDINGS

During the past year our understanding of the effect of omega-3 depletion on the structure and function of the brain has been furthered by research examining human brain tissue and by studies utilizing animal models of depression. Human and animal research has also provided further evidence for omega-3 affecting mood via its anti-inflammatory effects. Previous clinical trials indicated that omega-3 can be effective as an adjunctive treatment for those with treatment-resistant depression. More recent clinical trial data indicate that omega-3 may also be an effective monotherapy for childhood depression and for depressed mood in patients who engage in recurrent self-harm. The recent clinical trial data regarding omega-3 as a treatment for bipolar disorder are inconclusive, however, and clinical trials in postnatal depression are still lacking.

SUMMARY

This article reviews the most important recent papers in this burgeoning and interesting research area.

Omega-3 fatty acids as treatments for mental illness: which disorder and which fatty acid?

BACKGROUND

A growing number of observational and epidemiological studies have suggested that mental illness, in particular mood disorders, is associated with reduced dietary intake and/or cellular abundance of omega-3 polyunsaturated fatty acids (PUFA). This has prompted researchers to test the efficacy of omega-3 PUFA in a range of different psychiatric disorders. We have critically reviewed the double blind placebo controlled clinical trials published prior to April 2007 to determine whether omega-3 PUFA are likely to be efficacious in these disorders.

RESULTS

Most trials involved a small number of participants but were largely well designed. Omega-3 PUFA were well tolerated by both children and adults with mild gastrointestinal effects being the only consistently reported adverse event. For schizophrenia and borderline personality disorder we found little evidence of a robust clinically relevant effect. In the case of attention deficit hyperactivity disorder and related disorders, most trials showed at most small benefits over placebo. A limited meta-analysis of these trials suggested that benefits of omega-3 PUFA supplementation may be greater in a classroom setting than at home. Some evidence indicates that omega-3 PUFA may reduce symptoms of anxiety although the data is preliminary and inconclusive. The most convincing evidence for beneficial effects of omega-3 PUFA is to be found in mood disorders. A meta-analysis of trials involving patients with major depressive disorder and bipolar disorder provided evidence that omega-3 PUFA supplementation reduces symptoms of depression. Furthermore, meta-regression analysis suggests that supplementation with eicosapentaenoic acid may be more beneficial in mood disorders than with docosahexaenoic acid, although several confounding factors prevented a definitive conclusion being made regarding which species of omega-3 PUFA is most beneficial. The mechanisms underlying the apparent efficacy of omega-3 PUFA in mood disorders compared to schizophrenia are discussed as is a rational for the possibly greater efficacy of EPA compared to DHA.

CONCLUSION

While it is not currently possible to recommend omega-3 PUFA as either a mono- or adjunctive-therapy in any mental illness, the available evidence is strong enough to justify continued study, especially with regard to attentional, anxiety and mood disorders.