Association of fish and long-chain n-3 polyunsaturated fatty acid intakes with the occurrence of depressive episodes in middle-aged French men and women

Fish consumption and depression in Korean population: The Korea National Health and Nutrition Examination Survey, 2013-2021

BACKGROUND

Epidemiological studies in some populations showed that dietary intake of fish may be inversely associated with depression, but large studies in Korean population are limited. Thus, we investigated the association between fish consumption and depression, considering the serving size of fish, in Korean adults.

METHODS

This study was based on the data from the Korea National Health and Nutrition Examination Survey (2013-2021), which is a large nationally representative study of Korean population. Fish consumption was assessed with a 24-hour dietary recall, and physician-diagnosed depression status was assessed using questionnaires from the health interview survey. Multivariable logistic regression models adjusting for demographic, lifestyle, and dietary factors were used to calculate odds ratios (OR) and 95 % confidence intervals (CI) for depression.

RESULTS

A total of 31,632 adults aged 19-64 years were included in the analysis. After adjusting for covariates, highest fish consumption (≥4 servings/week) was significantly associated with 26 % lower odds of depression compared to the lowest fish consumption (<1 servings/week) (OR 0.74; 95 % CI, 0.60-0.92, P for trend = 0.007). A similar inverse association was found in female adults (OR 0.76; 95 % CI, 0.59-0.97, P for trend = 0.018), but no significant association was found in male adults (OR 0.75; 95 % CI, 0.49-1.15, P for trend = 0.223).

LIMITATIONS

Since KNHANES is a cross-sectional study, it is difficult to evaluate the causal relationship between fish consumption and depression risk.

CONCLUSIONS

This study results suggest that high fish consumption is associated with lower risk of depression in Korean adults, especially in female adults.

Nordic diet and its benefits in neurological function: a systematic review of observational and intervention studies

Introduction

Neurological disorders have been considered the major contributors to global long-term disability and lower quality of life. Lifestyle factors, such as dietary patterns, are increasingly recognized as important determinants of neurological function. Some dietary behaviors, such as Nordic diet (ND) were likely to have protective effects on brain function. However, an understanding of the effectiveness of the ND pattern to improve neurological function and brain health is not fully understood. We review the current evidence that supports the ND pattern in various aspects of neurological function and addresses both proven and less established mechanisms of action based on its food ingredients and biochemical compounds.

Methods

In this systematic review, PubMed, Web of Science, and Scopus databases were searched from inception to February 2023. Observational and intervention studies were included.

Results

Of the 627 screened studies, 5 observational studies (including three cohorts and two cross-sectional studies) and 3 intervention studies investigating the association between ND and neurological function. Observational studies investigated the association of ND with the following neurological functions: cognition, stroke, and neuropsychological function. Intervention studies investigated the effects of ND on cognition and depression.

Discussion

Despite the limited literature on ND and its association with neurological function, several aspects of ND may lead to some health benefits suggesting neuroprotective effects. The current state of knowledge attributes the possible effects of characteristic components of the ND to its antioxidant, anti-inflammatory, lipid-lowering, gut-brain-axis modulating, and ligand activities in cell signaling pathways. Based on existing evidence, the ND may be considered a recommended dietary approach for the improvement of neurological function and brain health.

Systematic review registration

[https://www.crd.york.ac.uk/prospero/], identifier [CRD2023451117].

A Revision on the Effectiveness of Omega-3 Polyunsaturated Fatty Acids as Monotherapy in the Treatment of Major Depressive Disorder

BACKGROUND

Insufficient effectiveness and a difficult tolerability profile of antidepressant drugs for the treatment of major depressive disorder (MDD) have been reported, and polyunsaturated fatty acids (PUFAs) have been posited as reliable therapeutic alternatives. The present study investigated the efficacy of omega-3 PUFAs as monotherapy for MDD.

METHODS

Two well-trained reviewers independently looked at the most significant randomized clinical trials (RCTs) from the PubMed database regarding PUFAs' employment in MDD compared to placebo; "major depressive disorder" and "omega-3 fatty acids," or "omega-6 fatty acids," or "polyunsaturated fatty acids (PUFA)," or "n - 3 polyunsaturated fatty acids," or "eicosapentaenoic acid (EPA)," or "docosahexaenoic acid (DHA)" were used as the medical subject keywords.

RESULTS

Of the initial 96 potential RCTs based on titles and abstracts, 82 studies did not meet the inclusion criteria and were excluded. Six studies were excluded from the remaining 14 after full text revision. Eight RCTs met all the inclusion/exclusion criteria without reporting clear evidence of PUFAs' effectiveness in the treatment of MDD.

CONCLUSION

At present, there is no opportunity to recommend the use of omega-3 PUFAs monotherapy for the treatment of MDD, although their supplementation may be useful in some specific populations.

New Insights into Depressive Disorder with Respect to Low-Grade Inflammation and Fish Oil Intake

Unipolar depression has been recognized as one of the major diseases by the World Health Organization in the 21st century. The etiology of depression is complicated and includes genetic factors, stress, aging, and special physical status (pregnancy, metabolic syndrome, and trauma). Numerous animal and human studies have demonstrated that n-3 polyunsaturated fatty acids (n-3 PUFAs) are highly correlated to cognition and depression. These nutritional antidepressants, including EPA and DHA, have a range of neurobiological activities contributing to their potential antidepressant effects. Our preclinical and clinical studies have indicated that n-3 PUFA supplementation in addition to standard antidepressant medications may provide synergistic neuroprotective and antioxidant/inflammatory effects. To translate our preliminary findings into clinical application, this paper reviews the existing evidence on the antidepressant effects of n-3 PUFAs and the potential underlying mechanisms, which include modulation of chronic lowgrade inflammation and the corresponding changes in peripheral blood immune biomarkers.

Disentangling the Molecular Mechanisms of the Antidepressant Activity of Omega-3 Polyunsaturated Fatty Acid: A Comprehensive Review of the Literature

Major depressive disorders (MDDs) are often associated with a deficiency in long-chain omega-3 polyunsaturated fatty acids (ω-3 PUFAs), as well as signs of low-grade inflammation. Epidemiological and dietary studies suggest that a high intake of fish, the major source of ω-3 PUFAs, is associated with lower rates of MDDs. Meta-analyses of randomized placebo-controlled ω-3 PUFAs intervention-trials suggest that primarily eicosapentaenoic acid (EPA), but not docosahexaenoic acid (DHA), is responsible for the proposed antidepressant effect. In this review, we dissect the current biological knowledge on EPA and DHA and their bioactive lipid metabolites to search for a pharmacological explanation of this, to date, unexplained clinical observation. Through enzymatic conversion by cyclooxygenase (COX), lipoxygenase (ALOX), and cytochrome P-450 monooxygenase (CYP), EPA and DHA are metabolized to major anti-inflammatory and pro-resolving lipid mediators. In addition, both ω-3 PUFAs are precursors for endocannabinoids, with known effects on immunomodulation, neuroinflammation, food intake and mood. Finally, both ω-3 PUFAs are crucial for the structure and organization of membranes and lipid rafts. While most biological effects are shared by these two ω-3 PUFAs, some distinct features could be identified: (1) The preferential CYP monooxygenase pathway for EPA and EPA derived eicosanoids; (2) The high CB2 receptor affinities of EPA-derived EPEA and its epoxy-metabolite 17,18-EEQ-EA, while the DHA-derived endocannabinoids lack such receptor affinities; (3) The competition of EPA but not DHA with arachidonic acid (AA) for particular glycerophospholipids. EPA and AA are preferentially incorporated into phosphatidylinositols, while DHA is mainly incorporated into phosphatidyl-ethanolamine, -serine and -choline. We propose that these distinct features may explain the superior antidepressant activity of EPA rich ω-3 PUFAs and that these are potential novel targets for future antidepressant drugs.

Associations of n-3, n-6 Fatty Acids Intakes and n-6:n-3 Ratio with the Risk of Depressive Symptoms: NHANES 2009-2016

Many studies have explored the association between n-3 fatty acids and depression, but research on the associations of n-6 fatty acids and n-6:n-3 ratio with depression is more scarce, and the results are controversial. Therefore, we conducted this cross-sectional study to explore the associations of n-3 and n-6 fatty acid intakes and n-6:n-3 ratio with the risk of depressive symptoms using data from National Health and Nutrition Examination Survey (NHANES) 2009–2016. Dietary data on n-3 and n-6 fatty acids were obtained through two 24-h dietary recall interviews, and were adjusted by energy. Depressive symptoms were measured by PHQ-9 (nine-item Patient Health Questionnaire). We applied logistic regression and restricted cubic spline models to assess the relationships of n-3 and n-6 fatty acids intake and n-6:n-3 ratio with the risk of depressive symptoms. A total of 17,431 individuals over 18 years old were enrolled in this study. In the multivariate-adjusted model 2, compared with the lowest category, the highest odd ratios (ORs) with 95% confidence intervals (CIs) for n-3 fatty acid intake and n-6:n-3 ratio were 0.71 (0.55–0.92) and 1.66 (1.10–2.50), and middle OR (95% CI) for n-6 fatty acid intake was 0.72 (0.56–0.92), respectively. Our study suggests that n-3 and n-6 fatty acids intake were inversely associated with the risk of depressive symptoms, while the n-6:n-3 ratio was positively associated with the risk of depressive symptoms.

Fish consumption and risk of depression: Epidemiological evidence from prospective studies

INTRODUCTION

The evidence on the association of fish or omega-3 fatty acid intake with depression is inconsistent. We conducted a systematic review and meta-analysis of prospective cohort studies to examine this association.

METHODS

Database searches in PubMed and Web of Science were conducted to identify relevant articles published up to April 2018, which were supplemented by hand-searches of reference lists of the retrieved articles. Using a random-effects model, we calculated pooled relative risks (RR) of depression in relation to consumption of fish or omega-3 fatty acids after adjusting for potential confounders.

RESULTS

A total of 10 prospective cohort studies with 6672 cases of depression among 109 764 participants were included in the meta-analysis. The pooled adjusted RR of depression for the highest vs lowest category of fish consumption was 0.89 (95% CI: 0.80-0.99). The pooled adjusted RR of depression for the highest vs lowest category of omega-3 intake was 0.87 (95% CI: 0.74-1.04). In the dose-response analysis, the pooled adjusted RRs for an increment of 1 serving/week of fish consumption and 500 mg/day of omega-3 fatty acid intake were 0.89 (95% CI: 0.75-1.04) and 0.99 (95% CI: 0.94-1.04), respectively. There was no evidence of heterogeneity.

DISCUSSION

Our findings provide quantitative evidence for a modest inverse association between fish or omega-3 fatty acid intake and risk of depression, especially in women. These findings from the observational studies need to be confirmed through large randomized clinical trials of fish consumption or omega-3 fatty acid intake and risk of depression.

Polyunsaturated fatty acids for the primary and secondary prevention of cardiovascular disease

BACKGROUND

Evidence on the health effects of total polyunsaturated fatty acids (PUFA) is equivocal. Fish oils are rich in omega-3 PUFA and plant oils in omega-6 PUFA. Evidence suggests that increasing PUFA-rich foods, supplements or supplemented foods can reduce serum cholesterol, but may increase body weight, so overall cardiovascular effects are unclear.

OBJECTIVES

To assess effects of increasing total PUFA intake on cardiovascular disease and all-cause mortality, lipids and adiposity in adults.

SEARCH METHODS

We searched CENTRAL, MEDLINE and Embase to April 2017 and clinicaltrials.gov and the World Health Organization International Clinical Trials Registry Platform to September 2016, without language restrictions. We checked trials included in relevant systematic reviews.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing higher with lower PUFA intakes in adults with or without cardiovascular disease that assessed effects over 12 months or longer. We included full texts, abstracts, trials registry entries and unpublished data. Outcomes were all-cause mortality, cardiovascular disease mortality and events, risk factors (blood lipids, adiposity, blood pressure), and adverse events. We excluded trials where we could not separate effects of PUFA intake from other dietary, lifestyle or medication interventions.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles and abstracts, assessed trials for inclusion, extracted data, and assessed risk of bias. We wrote to authors of included trials for further data. Meta-analyses used random-effects analysis, sensitivity analyses included fixed-effects and limiting to low summary risk of bias. We assessed GRADE quality of evidence.

MAIN RESULTS

We included 49 RCTs randomising 24,272 participants, with duration of one to eight years. Eleven included trials were at low summary risk of bias, 33 recruited participants without cardiovascular disease. Baseline PUFA intake was unclear in most trials, but 3.9% to 8% of total energy intake where reported. Most trials gave supplemental capsules, but eight gave dietary advice, eight gave supplemental foods such as nuts or margarine, and three used a combination of methods to increase PUFA.Increasing PUFA intake probably has little or no effect on all-cause mortality (risk 7.8% vs 7.6%, risk ratio (RR) 0.98, 95% confidence interval (CI) 0.89 to 1.07, 19,290 participants in 24 trials), but probably slightly reduces risk of coronary heart disease events from 14.2% to 12.3% (RR 0.87, 95% CI 0.72 to 1.06, 15 trials, 10,076 participants) and cardiovascular disease events from 14.6% to 13.0% (RR 0.89, 95% CI 0.79 to 1.01, 17,799 participants in 21 trials), all moderate-quality evidence. Increasing PUFA may slightly reduce risk of coronary heart disease death (6.6% to 6.1%, RR 0.91, 95% CI 0.78 to 1.06, 9 trials, 8810 participants) andstroke (1.2% to 1.1%, RR 0.91, 95% CI 0.58 to 1.44, 11 trials, 14,742 participants, though confidence intervals include important harms), but has little or no effect on cardiovascular mortality (RR 1.02, 95% CI 0.82 to 1.26, 16 trials, 15,107 participants) all low-quality evidence. Effects of increasing PUFA on major adverse cardiac and cerebrovascular events and atrial fibrillation are unclear as evidence is of very low quality.Increasing PUFA intake probably slightly decreases triglycerides (by 15%, MD -0.12 mmol/L, 95% CI -0.20 to -0.04, 20 trials, 3905 participants), but has little or no effect on total cholesterol (mean difference (MD) -0.12 mmol/L, 95% CI -0.23 to -0.02, 26 trials, 8072 participants), high-density lipoprotein (HDL) (MD -0.01 mmol/L, 95% CI -0.02 to 0.01, 18 trials, 4674 participants) or low-density lipoprotein (LDL) (MD -0.01 mmol/L, 95% CI -0.09 to 0.06, 15 trials, 3362 participants). Increasing PUFA probably has little or no effect on adiposity (body weight MD 0.76 kg, 95% CI 0.34 to 1.19, 12 trials, 7100 participants).Effects of increasing PUFA on serious adverse events such as pulmonary embolism and bleeding are unclear as the evidence is of very low quality.

AUTHORS' CONCLUSIONS

This is the most extensive systematic review of RCTs conducted to date to assess effects of increasing PUFA on cardiovascular disease, mortality, lipids or adiposity. Increasing PUFA intake probably slightly reduces risk of coronary heart disease and cardiovascular disease events, may slightly reduce risk of coronary heart disease mortality and stroke (though not ruling out harms), but has little or no effect on all-cause or cardiovascular disease mortality. The mechanism may be via TG reduction.

Polyunsaturated fatty acids for the primary and secondary prevention of cardiovascular disease

BACKGROUND

Evidence on the health effects of total polyunsaturated fatty acids (PUFA) is equivocal. Fish oils are rich in omega-3 PUFA and plant oils in omega-6 PUFA. Evidence suggests that increasing PUFA-rich foods, supplements or supplemented foods can reduce serum cholesterol, but may increase body weight, so overall cardiovascular effects are unclear.

OBJECTIVES

To assess effects of increasing total PUFA intake on cardiovascular disease and all-cause mortality, lipids and adiposity in adults.

SEARCH METHODS

We searched CENTRAL, MEDLINE and Embase to April 2017 and clinicaltrials.gov and the World Health Organization International Clinical Trials Registry Platform to September 2016, without language restrictions. We checked trials included in relevant systematic reviews.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing higher with lower PUFA intakes in adults with or without cardiovascular disease that assessed effects over 12 months or longer. We included full texts, abstracts, trials registry entries and unpublished data. Outcomes were all-cause mortality, cardiovascular disease mortality and events, risk factors (blood lipids, adiposity, blood pressure), and adverse events. We excluded trials where we could not separate effects of PUFA intake from other dietary, lifestyle or medication interventions.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles and abstracts, assessed trials for inclusion, extracted data, and assessed risk of bias. We wrote to authors of included trials for further data. Meta-analyses used random-effects analysis, sensitivity analyses included fixed-effects and limiting to low summary risk of bias. We assessed GRADE quality of evidence.

MAIN RESULTS

We included 49 RCTs randomising 24,272 participants, with duration of one to eight years. Eleven included trials were at low summary risk of bias, 33 recruited participants without cardiovascular disease. Baseline PUFA intake was unclear in most trials, but 3.9% to 8% of total energy intake where reported. Most trials gave supplemental capsules, but eight gave dietary advice, eight gave supplemental foods such as nuts or margarine, and three used a combination of methods to increase PUFA.Increasing PUFA intake probably has little or no effect on all-cause mortality (risk 7.8% vs 7.6%, risk ratio (RR) 0.98, 95% confidence interval (CI) 0.89 to 1.07, 19,290 participants in 24 trials), but probably slightly reduces risk of coronary heart disease events from 14.2% to 12.3% (RR 0.87, 95% CI 0.72 to 1.06, 15 trials, 10,076 participants) and cardiovascular disease events from 14.6% to 13.0% (RR 0.89, 95% CI 0.79 to 1.01, 17,799 participants in 21 trials), all moderate-quality evidence. Increasing PUFA may slightly reduce risk of coronary heart disease death (6.6% to 6.1%, RR 0.91, 95% CI 0.78 to 1.06, 9 trials, 8810 participants) andstroke (1.2% to 1.1%, RR 0.91, 95% CI 0.58 to 1.44, 11 trials, 14,742 participants, though confidence intervals include important harms), but has little or no effect on cardiovascular mortality (RR 1.02, 95% CI 0.82 to 1.26, 16 trials, 15,107 participants) all low-quality evidence. Effects of increasing PUFA on major adverse cardiac and cerebrovascular events and atrial fibrillation are unclear as evidence is of very low quality.Increasing PUFA intake slightly reduces total cholesterol (mean difference (MD) -0.12 mmol/L, 95% CI -0.23 to -0.02, 26 trials, 8072 participants) and probably slightly decreases triglycerides (MD -0.12 mmol/L, 95% CI -0.20 to -0.04, 20 trials, 3905 participants), but has little or no effect on high-density lipoprotein (HDL) (MD -0.01 mmol/L, 95% CI -0.02 to 0.01, 18 trials, 4674 participants) or low-density lipoprotein (LDL) (MD -0.01 mmol/L, 95% CI -0.09 to 0.06, 15 trials, 3362 participants). Increasing PUFA probably causes slight weight gain (MD 0.76 kg, 95% CI 0.34 to 1.19, 12 trials, 7100 participants).Effects of increasing PUFA on serious adverse events such as pulmonary embolism and bleeding are unclear as the evidence is of very low quality.

AUTHORS' CONCLUSIONS

This is the most extensive systematic review of RCTs conducted to date to assess effects of increasing PUFA on cardiovascular disease, mortality, lipids or adiposity. Increasing PUFA intake probably slightly reduces risk of coronary heart disease and cardiovascular disease events, may slightly reduce risk of coronary heart disease mortality and stroke (though not ruling out harms), but has little or no effect on all-cause or cardiovascular disease mortality. The mechanism may be via lipid reduction, but increasing PUFA probably slightly increases weight.

Fish consumption and depression in Korean adults: the Korea National Health and Nutrition Examination Survey, 2013-2015

BACKGROUND/OBJECTIVES

There is a growing body of evidence that supports the potential role of fish consumption in relation to depression, but the data in Korean population is scarce. Thus, we examined the association between fish consumption and depression in Korean adults.

SUBJECTS/METHODS

We conducted a cross-sectional study in 9183 Korean adults aged 19-64 years who participated in the 6TH Korea National Health and Nutrition Examination Survey (2013-2015), which is a large nationally representative study of Korean population. Fish consumption and depression status were assessed using questionnaires. Multivariable logistic regression models were used to compute odds ratios (ORs) and 95% confidence intervals (CIs) for physician-diagnosed clinical depression.

RESULTS

Out of the 9183 subjects, 389 (4.2%) were diagnosed with depression. After adjusting for potential confounders, the multivariable-adjusted ORs for clinical depression across fish consumption were 1.00 (reference) for <1 time/week, 0.76 (95% CI: 0.56-1.04) for 1-3 times/week and 0.52 (95% CI: 0.37-0.74) for ≥4 times/week (P for trend = 0.0005). The inverse association for ≥4 times/week of fish consumption was stronger in women (OR = 0.44, 95% CI: 0.29-0.67, P for trend < .0001), but there was no significant association in men.

CONCLUSIONS

Our findings suggest that high consumption of fish is associated with lower odds of depression in Korean adults, particularly in women. These results warrant further prospective studies to verify the association between fish consumption and risk of depression in Korean adults.

Diet quality and depression risk: A systematic review and dose-response meta-analysis of prospective studies

BACKGROUND

It has been claimed that the quality of a diet is associated with the incidence of depressive disorders. We sought to investigate the evidence for this claim.

METHODS

Systematic searches were performed up to March 6th, 2017 in order to identify prospective cohort studies that reported on exposure to dietary patterns or food groups and the incidence of depression/depressive symptoms. Data from 24 independent cohorts (totalling 1,959,217 person-years) were pooled in random-effects meta-analyses.

RESULTS

Adherence to a high-quality diet, regardless of type (i.e., healthy/prudent or Mediterranean), was associated with a lower risk of depressive symptoms over time (odds ratios ranged 0.64-0.78 in a linear dose-response fashion [P < 0.01]). A relatively low dietary inflammatory index was also associated with a somewhat lower incidence of depressive symptom (odds ratio = 0.81), although not in a dose-response fashion. Similar associations were found for the consumption of fish and vegetables (odds ratios 0.86 and 0.82 respectively) but not for other high quality food groups (e.g., fruit). Studies that controlled for depression severity at baseline or that used a formal diagnosis as outcome did not yield statistically significant findings. Adherence to low quality diets and food groups was not associated with higher depression incidence.

LIMITATIONS

Our ability to detect confounders was only limited.

CONCLUSION

There is evidence that a higher quality of a diet is associated with a lower risk for the onset of depressive symptoms, but not all available results are consistent with the hypothesis that diet influences depression risk. Prospective studies that control for relevant confounders such as obesity incidence and randomized controlled prevention trials are needed to increase the validity of findings in this field.

Polyunsaturated fatty acid composition and childhood adversity: Independent correlates of depressive symptom persistence

Childhood experiences, personality, and polyunsaturated essential fatty acid (PUFA) composition have all been shown to affect the likelihood of depressive symptoms. Few studies have addressed relationships between these factors in their influence on the occurrence or course of depressive symptoms. The following analysis was designed to do so. Subjects, 15-20 years old, had either begun antidepressant treatment within the preceding month (n = 88), or had never taken psychiatric medications (n = 92). Baseline assessments included a structured diagnostic interview, the self-completed Multiphasic Personality Questionnaire, and a determination of plasma PUFA phospholipid composition. Depressive symptom levels were assessed at baseline and again at 4, 8 and 12 months. Omega-3 composition and general childhood trauma scores were unrelated to each other but both correlated, in predicted directions, with negative emotionality. Low omega-3 composition and history of childhood trauma were associated with persistence of depressive symptoms during follow-up, largely through their effects on negative emotionality. Negative emotionality appears to comprise a final common pathway to depressive disorder through which the diverse risk factors of childhood adversity and low omega-3 composition are expressed.

Cardiovascular diseases, depression disorders and potential effects of omega-3 fatty acids

Cardiovascular disease (CVD) and depressive disorders (DD) are two of the most prevalent health problems in the world. Although CVD and depression have different origin, they share some common pathophysiological characteristics and risk factors, such as the increased production of proinflammatory cytokines, endothelial dysfunction, blood flow abnormalities, decreased glucose metabolism, elevated plasma homocysteine levels, oxidative stress and disorder in vitamin D metabolism. Current findings confirm the common underlying factors for both pathologies, which are related to dramatic dietary changes in the mid-19th century. By changing dietary ratio of omega-6 to omega-3 fatty acids from 1:1 to 15-20:1 some changes in metabolism were induced, such as increased pro-inflammatory mediators and modulations of different signaling pathways following pathophysiological response related to both, cardiovascular diseases and depressive disorders.

Dietary n-3 PUFA, fish consumption and depression: A systematic review and meta-analysis of observational studies

BACKGROUND

Fish consumption and n-3 polyunsaturated fatty acids (PUFA) have been hypothesized to exert preventive effects toward depressive disorders, but findings are contrasting. We aimed to systematically review and perform meta-analysis of results from observational studies exploring the association between fish, n-3 PUFA dietary intake, and depression.

METHODS

A search on the main bibliographic source of the observational studies up to August 2015 was performed. Random-effects models of the highest versus the lowest (reference) category of exposure and dose-response meta-analysis were performed.

RESULTS

A total of 31 studies including 255,076 individuals and over 20,000 cases of depression, were examined. Analysis of 21 datasets investigating relation between fish consumption and depression resulted in significant reduced risk (RR=0.78, 95% CI: 0.69, 0.89), with a linear dose-response despite with moderate heterogeneity. Pooled risk estimates of depression for extreme categories of both total n-3 PUFA and fish-derived n-3 PUFA [eicosapentaenoic acid (EPA)+docosahexaenoic acid (DHA)] resulted in decreased risk for the highest compared with the lowest intake (RR=0.78, 95% CI: 0.67, 0.92 and RR=0.82, 95% CI: 0.73, 0.92, respectively) and dose-response analysis revealed a J-shaped association with a peak decreased risk for 1.8g/d intake of n-3 PUFA (RR=0.30, 95% CI: 0.09, 0.98).

LIMITATION

Design of the studies included and confounding due to lack adjustment for certain variables may exist.

CONCLUSIONS

The present analysis supports the hypothesis that dietary n-3 PUFA intake are associated with lower risk of depression.

Effects of Walnut Consumption on Mood in Young Adults-A Randomized Controlled Trial

Walnuts contain a number of potentially neuroprotective compounds like vitamin E, folate, melatonin, several antioxidative polyphenols and significant amounts of ω-3 fatty acids. The present study sought to determine the effect of walnuts on mood in healthy volunteers. Sixty-four college students were randomly assigned to two treatment sequences in a crossover fashion: walnut-placebo or placebo-walnut. At baseline mood was assessed using Profiles of Mood States (POMS). Data was collected again after eight weeks of intervention. After six-weeks of washout, the intervention groups followed the diets in reverse order. Data was collected once more at the end of the eight-week intervention period. No significant changes in mood were observed in the analyses with both genders combined and in females. However, we have observed a significant medium effect size improvement in the Total Mood Disturbance score (-27.49%, p = 0.043, Cohen's d = 0.708) in males. In non-depressed healthy young males, walnuts seem to have the ability to improve mood.

Adherence to dietary guidelines as a protective factor against chronic or recurrent depressive symptoms in the French SU.VI.MAX cohort

Several studies have suggested that a healthier overall diet was associated with a lower risk of depression, which is one of the main causes of disability worldwide. Our objective was to investigate the prospective association of adherence to dietary guidelines at midlife, measured by the French Programme National Nutrition Santé-Guideline Score (PNNS-GS), with chronic or recurrent depressive symptoms. The association between the PNNS-GS and chronic or recurrent depressive symptoms was evaluated among participants of the French Supplémentation en Vitamines et Minéraux AntioXydants (SU.VI.MAX) cohort with available data on the PNNS-GS at baseline (1994-1996) and on the Center for Epidemiologic Studies-Depression Scale (CES-D) in 1996-1997 and follow-up (2007-2009) (n=3328). Chronic or recurrent depressive symptoms were defined by a CES-D score ≥16 at baseline and follow-up. Odds ratios (OR) and 95%-confidence intervals (95%-CI) were estimated across quartiles (Q) of the PNNS-GS, using logistic regression models. In our study, 10.1% of the participants (n=335) had chronic or recurrent depressive symptoms. After adjustment for potential confounders, the PNNS-GS was inversely associated with chronic or recurrent depressive symptoms: OR_{Q4 vs. Q1}: 0.42 (95%-CI: 0.29, 0.60). Modelling the PNNS-GS as a continuous variable yielded similar results: OR for a 1-point increment in the PNNS-GS: 0.86 (95%-CI: 0.80, 0.92). In conclusion, higher adherence to French dietary guidelines at midlife was associated with a lower rate of chronic or recurrent depressive symptoms, which suggests that these recommendations may be highly relevant, not only to avoid chronic diseases, but also for the overall well-being.

Cross-sectional association between serum concentrations of n-3 long-chain PUFA and depressive symptoms: results in Japanese community dwellers

The effect of n-3 long-chain PUFA (n-3 LCPUFA) on depression in healthy subjects is unclear, and most of the previous studies have focused on populations eating Western diets with lower fish intake. The present study investigated the association between blood levels of n-3 LCPUFA and depressive symptoms in Japanese community dwellers with higher n-3 LCPUFA blood levels. A cross-sectional study was conducted from 2006 to 2008, including 1050 men and 1073 women aged 40 years or older from the National Institute for Longevity Sciences – the Longitudinal Study of Aging. The Center for Epidemiologic Studies Depression Scale (CES-D) was used to assess depressive symptoms. Multiple logistic regression analysis was performed to estimate the OR and 95 % CI for a CES-D score ≥16. Serum concentrations of n-3 PUFA, but not n-6 PUFA, were inversely associated with depressive symptoms. Compared with the lowest quintile, the adjusted OR for serum EPA at the fourth and fifth quintiles were 0·55 (95 % CI 0·35, 0·85) and 0·64 (95 % CI 0·42, 0·98), respectively, and at the fifth quintile for DHA it was 0·58 (95 % CI 0·37, 0·92), for the presence of depressive symptoms (P_{for trend}=0·013 and 0·011, respectively). Serum levels of EPA and DHA were inversely associated with depressive symptoms in Japanese community dwellers with higher blood levels of n-3 LCPUFA, suggesting that n-3 LCPUFA intakes corresponding to higher levels in a Japanese population may have implications for a lower prevalence of depression.

Involvement of dietary Fatty acids in multiple biological and psychological functions, in morbidly obese subjects

BACKGROUND

Fatty acid (FA) profile is often altered, in morbidly obese subjects, both before and after bariatric surgery. We measured FA plasma levels before and 6 months after Roux-en-Y gastric bypass (RYGB), in order to evaluate their relationship with different biological and psychological parameters and the impact of RYGB on the FA plasma levels.

METHODS

Thirty eight morbidly obese patients were investigated before RYGB, and 28 of them were reexamined 6 months postoperatively. Anxiety, depression, and quality of life were evaluated by validated questionnaires. Plasma FA (saturated, monounsaturated, polyunsaturated ω-6 and ω-3), vitamins A and E, fasting insulinemia, and high-sensitive C-reactive protein (hs-CRP) were measured.

RESULTS

Before surgery, ω-3 polyunsaturated FA and vit A showed significant negative relationship with fasting insulinemia (γ-linolenic p = 0.03, eicosapentaenoic, vit A p = 0.01) and hs-CRP (eicosapentaenoic p = 0.03, vit A p = 0.02) and a positive link with HDL cholesterol (γ-linolenic p = 0.03, vit A p = 0.02). Depression score was significantly and negatively linked with palmitoleic (p = 0.03), γ-linolenic (p = 0.006), dihomo-γ-linolenic (p = 0.02), and α-linolenic (p = 0.03) acids. After surgery, FA and both vit A and E were significantly reduced. Vit A levels were below 2.4 μmol/l in 63 % of the patients, preoperatively, and in 79 % after surgery. Preoperative levels of linoleic acid were significantly related with the postoperative weight reduction (p = 0.0006).

CONCLUSIONS

FA are involved in several biological and psychological functions. The RYGB-induced reduction of FA could have deleterious consequences on vitamin absorption, metabolism, and depression. Thus, the surveillance of FA levels is of primary importance both before and after RYGB.

Interactions between psychological stress and drinking status in relation to diet among middle-aged men and women: a large-scale cross-sectional study in Japan

The aim of this study was to investigate the interaction between psychological stress (PS) and drinking status in relation to diet among middle-aged Japanese men and women in a large-scale cross-sectional study. The study population included 5,587 middle-aged Japanese men and 2,718 middle-aged Japanese women who underwent annual health checkups. The subjects were divided into 2 groups (non-drinkers and drinkers) and classified as having low, moderate, or high self-reported PS levels. Energy-adjusted food and nutrient consumption was assessed with a validated food frequency questionnaire. Using a general linear model, food and nutrient consumption was estimated for each self-reported PS level in the 2 groups (non-drinkers and drinkers) and the interactions between self-reported PS levels and drinking status were calculated. In men, pork and beef; squid, octopus, shrimp, and clams; eggs; mushrooms; Japanese-style sweets; ice cream; bread; Chinese noodles; coffee; and soda as foods and protein, animal protein, fat, animal fat, carbohydrate, monounsaturated fatty acid, polyunsaturated fatty acid (PUFA), n-3 PUFA, n-6 PUFA, cholesterol, vitamin D, vitamin B2, vitamin B6, vitamin B12, niacin, pantothenic acid, magnesium, phosphorus, and zinc as nutrients significantly interacted with self-reported PS levels and drinking status (p for interaction <0.05 for all). No specific interactions were found in women. These findings suggest interactions between PS levels and drinking status with consumption of some foods and nutrients, especially macronutrient intake, in men but not in women.

Associations of the Ratios of n-3 to n-6 Dietary Fatty Acids With Longitudinal Changes in Depressive Symptoms Among US Women

In the present study, we examined longitudinal changes in self-reported depressive symptoms (and related domains) in relation to baseline intakes of n-3 fatty acids (absolute and relative to n-6 fatty acids). Sex-specific associations were evaluated in a prospective cohort of adults (n = 2,053) from Baltimore, Maryland, who were 30-64 years of age at baseline and were followed for a mean of 4.65 (standard deviation, 0.93) years (2004-2013). Using mean intakes of n-3 and n-6 fatty acids reported on two 24-hour dietary recalls, we estimated the ratios of n-3 to n-6 fatty acids for both highly unsaturated fatty acids (≥20 carbon atoms) (HUFAs) and polyunsaturated fatty acids (≥18 carbon atoms) (PUFAs). Outcomes included total and domain-specific scores on the 20-item Center for Epidemiologic Studies-Depression scale. Based on mixed-effects regression models, among women, both higher n-3 HUFA:n-6 PUFA and n-3 PUFA:n-6 PUFA ratios were associated with a slower rate of increase in total Center for Epidemiologic Studies-Depression scores over time. Higher n-3 HUFA:n-6 HUFA ratios were associated with slower increases in somatic complaints in men, whereas among women, higher n-3 HUFA:n-6 PUFA and n-3 PUFA:n-6 PUFA ratios were both linked to putative longitudinal improvement in positive affect over time. Among US adults, n-3:n-6 dietary fatty acid ratio was associated with longitudinal changes in depressive symptoms, with a higher ratio linked to a slower increase in depressive symptoms over time, particularly among women.

Dietary antioxidant intake and its association with cognitive function in an ethnically diverse sample of US adults

BACKGROUND

Dietary antioxidants can inhibit reactions accompanying neurodegeneration and thus prevent cognitive impairment. We describe associations of dietary antioxidants with cognitive function in a large biracial population, while testing moderation by sex, race, and age and mediation by depressive symptoms.

METHODS

This was a cross-sectional analysis of 1274 adults (541 men and 733 women) aged 30 to 64 years at baseline (mean [standard deviation] = 47.5 [9.3]) in the Healthy Aging in Neighborhoods of Diversity Across the Lifespan Study, Baltimore city, MD. Cognitive performance in the domains of memory, language/verbal, attention, spatial, psychomotor speed, executive function, and global mental status were assessed. The 20-item Center for Epidemiologic Studies Depression Scale was used to measure depressive symptoms. Dietary intake was assessed with two 24-hour recalls, estimating daily consumption of total carotenoids and vitamins A, C, and E per 1000 kcal.

RESULTS

Among key findings, 1 standard deviation (∼ 2.02 mg/1000 kcal) higher vitamin E was associated with a higher score on verbal memory, immediate recall (β = +0.64 [0.19], p = .001), and better language/verbal fluency performance (β = +0.53 [0.16], p = .001), particularly among the younger age group. Women with higher vitamin E intake (β = +0.68 [0.21], p = .001) had better performance on a psychomotor speed test. The vitamin E-verbal memory association was partially mediated by depressive symptoms (proportion mediated = 13%-16%).

CONCLUSIONS

In sum, future cohort studies and dietary interventions should focus on associations of dietary vitamin E with cognitive decline, specifically for domains of verbal memory, verbal fluency, and psychomotor speed.

Difference in diet between a general population national representative sample and individuals with alcohol use disorders, but not individuals with depressive or anxiety disorders

BACKGROUND

Mental disorders influence diet and food consumption, but there is a lack of consistent findings.

AIMS

To investigate food consumption, nutrient intakes and serum metabolic biomarkers in depressive, anxiety and alcohol use disorders in comparison with the remaining from a population-based nationwide sample.

METHODS

The study was based on the Health 2000 Survey data of which 5504 subjects aged 30 and over (3009 women and 2495 men) were used for the analysis. Depressive disorder, anxiety disorders and alcohol use disorders were diagnosed using the Composite International Diagnostic Interview (M-CIDI). The consumption of food and beverage items, and nutrient intakes were measured with a validated food frequency questionnaire, and the concentrations of biomarkers were determined in blood samples.

RESULTS

Overall, no similar differences with both genders were found in the intakes of energy, dietary fibre or macronutrients or in biomarkers in depressive or anxiety disorders. Women suffering from depressed disorder consumed more soft drinks (P = 0.034) and women suffering from anxiety disorders consumed more oils (P = 0.001), polyunsaturated fatty acids (P = 0.001) and less potatoes (P = 0.002) than the remaining participants. Men suffering from depressive disorder consumed less sweets and chocolate (P = 0.001) and men with anxiety disorder consumed more tea (P = 0.033) compared with the remaining participants. In alcohol use disorders, the intake of carbohydrate was lower in both genders (P = 0.001 for women, P = 0.001 for men).

CONCLUSIONS

A difference in the usual diet exists between individuals with alcohol use disorders and the remaining participants on a population level. No consistent difference in both genders between those with depressive or anxiety disorders and the remaining was found.

Dietary patterns are associated with the prevalence of elevated depressive symptoms and the risk of getting a hospital discharge diagnosis of depression in middle-aged or older Finnish men

BACKGROUND

Previous studies assessing the role of dietary factors in depression have mainly focused on nutrients, while the association between dietary patterns and depression is less studied.

OBJECTIVE

The aim was to assess the role of dietary patterns in depression in both cross-sectional and prospective analyses.

DESIGN

The study population consisted of 1003 Finnish middle-aged or older men from the Kuopio Ischemic Heart Disease Risk Factor Study. Food consumption was assessed by food frequency questionnaire in 1991-1993 and dietary patterns from 25 predefined food groups were extracted by factor analysis. Depressive symptoms were assessed with the self-administered Human Population Laboratory Depression Scale, cut-off point of five or more indicating elevated depressive symptoms.

RESULTS

Altogether 72 (7.2%) subjects had elevated depressive symptoms. Three dietary patterns were identified: "prudent", "Western" and "mixed". In cross-sectional analysis, after adjustments for age, examination year, BMI, smoking, alcohol consumption, education, marital status, leisure-time physical activity, history of mental illness and cardiovascular disease the prudent dietary pattern was associated with a 25% lower prevalence of elevated depressive symptoms (OR: 0.75; 95% CI: 0.57, 0.99; P=0.036), whereas the Western dietary pattern was associated with increased prevalence of elevated depressive symptoms (OR: 1.41; 95% CI: 1.08, 1.84; P=0.011). In the prospective analysis (16.5 follow-up years), the prudent dietary pattern was inversely associated with the risk of getting a hospital discharge diagnosis of depression (HR: 0.66; 95% CI 0.47, 0.93; P=0.018).

CONCLUSIONS

Adherence to healthy dietary pattern is associated with lower risk of getting a hospital discharge diagnosis of depression.

Omega-3 fatty acids and depression: scientific evidence and biological mechanisms

The changing of omega-6/omega-3 polyunsaturated fatty acids (PUFA) in the food supply of Western societies occurred over the last 150 years is thought to promote the pathogenesis of many inflammatory-related diseases, including depressive disorders. Several epidemiological studies reported a significant inverse correlation between intake of oily fish and depression or bipolar disorders. Studies conducted specifically on the association between omega-3 intake and depression reported contrasting results, suggesting that the preventive role of omega-3 PUFA may depend also on other factors, such as overall diet quality and the social environment. Accordingly, tertiary prevention with omega-3 PUFA supplement in depressed patients has reached greater effectiveness during the last recent years, although definitive statements on their use in depression therapy cannot be yet freely asserted. Among the biological properties of omega-3 PUFA, their anti-inflammatory effects and their important role on the structural changing of the brain should be taken into account to better understand the possible pathway through which they can be effective both in preventing or treating depression. However, the problem of how to correct the inadequate supply of omega-3 PUFA in the Westernized countries' diet is a priority in order to set food and health policies and also dietary recommendations for individuals and population groups.

ω-3 fatty acid intakes are inversely related to elevated depressive symptoms among United States women

Evidence that depressive symptoms are inversely related to n-3 (ω-3) fatty acids is growing among United States adults. We assessed whether self-reported depressive symptoms were inversely associated with n-3 fatty acid intakes by using a cross-sectional study in 1746 adults (aged 30-65 y) in Baltimore City, MD (2004-2009). The 20-item Center for Epidemiologic Studies-Depression Scale (CES-D) was used, with a CES-D score ≥16 suggestive of elevated depressive symptoms (EDS). By using the mean of two 24-h dietary recalls, n-3 highly unsaturated fatty acids (HUFAs; ≥20 carbons), n-3 polyunsaturated fatty acids (PUFAs; ≥18 carbons), and plausible ratios with n-6 (ω6) fatty acids were estimated. EDS prevalence was 18.1% among men and 25.6% among women. In women, the uppermost tertile (tertile 3) of n-3 PUFAs (compared with tertile 1) was associated with reduced odds of EDS by 49%, with a substantial sex differential. The n-3 PUFA:n-6:PUFA ratio was inversely related to EDS among women (tertile 2 vs. tertile 1, OR: 0.74; 95% CI: 0.41, 1.32; tertile 3 vs. tertile 1, OR: 0.47; 95% CI: 0.27, 0.83). A similar pattern was noted for n-3 HUFA:n-6 HUFA among women. For CES-D subscales, n-3 PUFA (% of energy) was inversely related to somatic complaints, whereas positive affect was directly related to n-3 HUFA (% of energy; total population and among women), n-3 HUFA:n-6 HUFA (women), and n-3 HUFA:n-6 PUFA (total population and among women). In sum, among United States women, higher intakes of n-3 fatty acids [absolute (n-3) and relative to n-6 fatty acids (n-3:n-6)] were associated with lower risk of elevated depressive symptoms, specifically in domains of somatic complaints (mainly n-3 PUFAs) and positive affect (mainly n-3 HUFAs).

Omega-3 fatty acids influence mood in healthy and depressed individuals

Depression is one of the most prevalent disorders in the United States, and rates of depression are higher for women than men. Despite their widespread use, drugs used in the treatment of depression are only moderately more effective than placebo in treating the disorder. Effective treatment of perinatal depression is of particular concern as treatment can influence both the mother and the developing child. Omega-3 polyunsaturated fatty acid (n-3 PUFA) supplementation may reduce symptoms of major depressive disorder and perinatal depression. The aim of the present review was to evaluate epidemiological studies examining PUFA intake and depressive symptoms in the general population, as well as double-blind, placebo-controlled trials assessing the influence of n-3 PUFA in healthy individuals and those with depression; specific consideration was given to perinatal depression and potential gender differences in the relationship. Although there is some evidence to suggest that n-3 PUFA intake is associated with reduced depressive symptoms, particularly in females, these results are generally limited to epidemiological studies, whereas results from randomized controlled trials are mixed.

Role of Long-Chain Omega-3 Fatty Acids in Psychiatric Practice

Nutrition plays a minor role in psychiatric practice which is currently dominated by a pharmacological treatment algorithm. An accumulating body of evidence has implicated deficits in the dietary essential long-chain omega-3 (LCn-3) fatty acids, eicosapenaenoic acid (EPA) and docosahexaenoic acid (DHA), in the pathophysiology of several major psychiatric disorders. LCn-3 fatty acids have an established long-term safety record in the general population, and existing evidence suggests that increasing LCn-3 fatty acid status may reduce the risk for cardiovascular disease morbidity and mortality. LCn-3 fatty acid supplementation has been shown to augment the therapeutic efficacy of antidepressant, mood-stabilizer, and second generation antipsychotic medications, and may additionally mitigate adverse cardiometabolic side-effects. Preliminary evidence also suggests that LCn-3 fatty acid supplementation may be efficacious as monotherapy for primary and early secondary prevention and for perinatal symptoms. The overall cost-benefit ratio endorses the incorporation of LCn-3 fatty acids into psychiatric treatment algorithms. The recent availability of laboratory facilities that specialize in determining blood LCn-3 fatty acid status and emerging evidence-based consensus guidelines regarding safe and efficacious LCn-3 fatty acid dose ranges provide the infrastructure necessary for implementation. This article outlines the rationale for incorporating LCn-3 fatty acid treatment into psychiatric practice.

Long term adequate n-3 polyunsaturated fatty acid diet protects from depressive-like behavior but not from working memory disruption and brain cytokine expression in aged mice

Converging epidemiological studies suggest that dietary essential n-3 polyunsaturated fatty acid (PUFA) are likely to be involved in the pathogenesis of mood and cognitive disorders linked to aging. The question arises as to whether the decreased prevalence of these symptoms in the elderly with high n-3 PUFA consumption is also associated with improved central inflammation, i.e. cytokine activation, in the brain. To answer this, we measured memory performance and emotional behavior as well as cytokine synthesis and PUFA level in the spleen and the cortex of adult and aged mice submitted to a diet with an adequate supply of n-3 PUFA in form of α-linolenic acid (α-LNA) or a n-3 deficient diet. Our results show that docosahexaenoic acid (DHA), the main n-3 PUFA in the brain, was higher in the spleen and cortex of n-3 adequate mice relative to n-3 deficient mice and this difference was maintained throughout life. Interestingly, high level of brain DHA was associated with a decrease in depressive-like symptoms throughout aging. On the opposite, spatial memory was maintained in adult but not in aged n-3 adequate mice relative to n-3 deficient mice. Furthermore, increased interleukin-6 (IL-6) and decreased IL-10 expression were found in the cortex of aged mice independently of the diets. All together, our results suggest that n-3 PUFA dietary supply in the form of α-LNA is sufficient to protect from deficits in emotional behavior but not from memory disruption and brain proinflammatory cytokine expression linked to age.

Dietary sources of omega 3 fatty acids: public health risks and benefits

Omega 3 fatty acids can be obtained from several sources, and should be added to the daily diet to enjoy a good health and to prevent many diseases. Worldwide, general population use omega-3 fatty acid supplements and enriched foods to get and maintain adequate amounts of these fatty acids. The aim of this paper was to review main scientific evidence regarding the public health risks and benefits of the dietary sources of omega-3 fatty acids. A systematic literature search was performed, and one hundred and forty-five articles were included in the results for their methodological quality. The literature described benefits and risks of algal, fish oil, plant, enriched dairy products, animal-derived food, krill oil, and seal oil omega-3 fatty acids.

Dietary omega 3 polyunsaturated fatty acids and Alzheimer's disease: interaction with apolipoprotein E genotype

Epidemiological studies suggest a protective role of omega-3 poly-unsaturated fatty acids (n-3 PUFA) against Alzheimer's disease (AD). However, most intervention studies of supplementation with n-3 PUFA have yielded disappointing results. One reason for such discordant results may result from inadequate targeting of individuals who might benefit from the supplementation, in particular because of their genetic susceptibility to AD. The ε4 allele of the apolipoprotein E gene (ApoE) is a genetic risk factor for late-onset AD. ApoE plays a key role in the transport of cholesterol and other lipids involved in brain composition and functioning. The action of n-3 PUFA on the aging brain might therefore differ according to ApoE polymorphism. The aim of this review is to examine the interaction between dietary fatty acids and ApoE genotype on the risk for AD. Carriers of the ε4 allele tend to be the most responsive to changes in dietary fat and cholesterol. Conversely, several epidemiological studies suggest a protective effect of long-chain n-3 PUFA on cognitive decline only in those who do not carry ε4 but with inconsistent results. An intervention study showed that only non-carriers had increased concentrations of long-chain n-3 PUFA in response to supplementation. The mechanisms underlying this gene-by-diet interaction on AD risk may involve impaired fatty acids and cholesterol transport, altered metabolism of n-3 PUFA, glucose or ketones, or modification of other risk factors of AD in ε4 carriers. Further research is needed to explain the differential effect of n-3 PUFA on AD according to ApoE genotype.

The effect of low-dose omega 3 fatty acids on the treatment of mild to moderate depression in the elderly: a double-blind, randomized, placebo-controlled study

Due to the rise in the social and economic costs of depression, new antidepressant medication with fewer side effects should be found. Several studies have shown that an association exists between ω-3 polyunsaturated fatty acids (ω-3 PUFAs) and depression. However, this association has not been clear enough in the elderly with mild to moderate depression. Sixty-six inhabitants of Kahrizak Charity Foundation participated in this double-blind, randomized, placebo-controlled study. Each participant was ≥ 65 years of age, had a Mini Mental State Exam of ≥ 22, and had scores ranging from 5 to 11 on the Geriatric Depression Scale-15 (GDS-15). During the 6 months, the drug group was treated daily with one gram of fish oil capsule containing 300 mg of both eicosapentaenoic acid and docosahexaenoic acid. No significant differences were noted between the groups in regard to level of education, use of antidepressant drugs, alcohol, tobacco use, history of chronic diseases, age, body mass index (BMI), high-sensitive C-reactive protein (hs-CRP), total cholesterol, and GDS-15 scores at baseline. After adjusting for cholesterol, BMI, and history of thyroid dysfunctions, a statistically significant difference was seen in GDS-15 scores between both groups. Furthermore, treatment with ω-3 PUFAs was clinically more effective in treating depression in comparison with the placebo. In this study, low-dose ω-3 PUFAs had some efficacy in the treatment of mild to moderate depression in elderly participants.

Fish consumption and severely depressed mood, findings from the first national nutrition follow-up study

The evidence obtained from prospective studies to support the hypothesis that fish consumption may improve mental status remains limited. The current study prospectively assessed a low frequency of fish consumption as a risk factor for depressed mood. Included were 5068 adults aged 25-74 years examined in 1971-1975 as the baseline of the First National Health and Nutrition Examination Survey Follow-up Study. Frequency of eating fish at baseline was obtained using a 3-month food frequency questionnaire. Severely depressed mood (SDM) was defined as the Center for Epidemiologic Studies Depression Scale scores ≥22 or taking anti-depressants. After an average of 10.6 years of follow-up, among men (n=2039), the percentage of individuals with SDM was 11.7%. Compared with frequent consumers (more than once a week), the odds ratios (ORs) were 1.43 (95%CI=0.66-3.11) and 2.08 (1.08-4.09) respectively for the men eating fish once a week and less than once a week (p for trend=0.03). Among women (n=3029), the percentage of individuals with SDM was 17.89%. The ORs were 1 (reference), 0.91 (0.68-1.22) and 1.15 (0.83-1.59) respectively for the women eating fish more than once, once, and less than once a week. These estimates were obtained after adjustment for indicators of social deprivation and major physical diseases. The study concluded that independently from social deprivation and physical diseases, low fish consumption was a risk factor for SDM among men. Further studies are needed to confirm these findings and elucidate mechanisms for the difference between men and women.

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.

A risk–benefit analysis approach to seafood intake to determine optimal consumption

Seafood provides n-3 long-chain PUFA (n-3 LC-PUFA), vitamins and minerals, which are essential to maintain good health. Moreover, seafood is a source of contaminants such as methylmercury, arsenic and persistent organic pollutants that may affect health. The aim of the present study was to determine in what quantities seafood consumption would provide nutritional benefits, while minimising the risks linked to food contaminants. Seafood was grouped into clusters using a hierarchical cluster analysis. Those nutrients and contaminants were selected for which it is known that seafood is a major source. The risk–benefit analysis consisted in using an optimisation model with constraints to calculate optimum seafood cluster consumption levels. The goal was to optimise nutrient intakes as well as to limit contaminant exposure with the condition being to attain recommended nutritional intakes without exceeding tolerable upper intakes for contaminants and nutrients, while taking into account background intakes. An optimum consumption level was calculated for adults that minimises inorganic arsenic exposure and increases vitamin D intake in the general population. This consumption level guarantees that the consumer reaches the recommended intake for n-3 LC-PUFA, Se and I, while remaining below the tolerable upper intakes for methylmercury, Cd, dioxins, polychlorobiphenyls, Zn, Ca and Cu. This consumption level, which is approximately 200 g/week of certain fatty fish species and approximately 50 g/week of lean fish, molluscs and crustaceans, has to be considered in order to determine food consumption recommendations in a public health perspective.

Inflammation in depression: is adiposity a cause?

Mounting evidence indicates that inflammation may play a significant role in the development of depression. Patients with depression exhibit increased inflammatory markers, and administration of cytokines and other inflammatory stimuli can induce depressive symptoms. Mechanisms by which cytokines access the brain and influence neurotransmitter systems relevant to depression have also been described, as have preliminary findings indicating that antagonizing inflammatory pathways may improve depressive symptoms. One primary source of inflammation in depression appears to be adiposity. Adipose tissue is a rich source of inflammatory factors including adipokines, chemokines, and cytokines, and a bidirectional relationship between adiposity and depression has been revealed. Adiposity is associated with the development of depression, and depression is associated with adiposity, reflecting a potentional vicious cycle between these two conditions which appears to center around inflammation. Treatments targeting this vicious cycle may be especially relevant for the treatment and prevention of depression as well as its multiple comorbid disorders such as cardiovascular disease, diabetes, and cancer, all of which have also been associated with both depression and inflammation.

Fatty acid status and maternal mental health

Maternal mental health (MMH) problems are a major public health concern with adverse consequences for women, their offspring and families. Intake of long-chain polyunsaturated fatty acids, especially the n-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid, which are found predominantly in cold water fish, has been associated with a range of mental health outcomes and may improve MMH. The demands for these fatty acids are increased during pregnancy and lactation, and may influence MMH as they are integral parts of cell membranes especially in the brain and play a role in physiological processes such as membrane fluidity and neurotransmitter function. Observational studies and intervention trials that have examined the role of fatty acids and MMH disorders especially post-partum depression (PPD) were identified using Pubmed and have been reviewed. Only three well-designed large prospective studies were identified; these studies examined the relationship between dietary intakes of n-3 fatty acids and fish during pregnancy, and found limited evidence of an association with PPD. Several intervention trials (n=8) have been done but generally suffer from small sample size and vary in terms of the study subject characteristics and timing, duration and dosage of the intervention. The results are mixed, but one recently completed large trial found no evidence of benefit among women who received DHA during pregnancy. Few studies have been conducted in developing countries, and gaps remain on the influence of other nutrient deficiencies, genetic polymorphisms that influence n-3 fatty acid synthesis and total fatty acid intake.

What is the effectiveness of the use of polyunsaturated fatty acid omega-3 in the treatment of depression?

This systematic review aims to identify the effect of polyunsaturated fatty acid omega-3 on depressive disorder. A bibliographical search was conducted in the databases SciELO, PubMed and ISIWEB. The keywords used were: "depression" and "omega-3 fatty acids", "depression" and "omega-3 polyunsaturated fatty acid", "depression" and "n-3 fatty acids". A total of 19 studies were identified: four double-blind randomized studies, four cohorts, two cross-sectional lines and nine case-controls. Only five studies presented dropout of less than 30% and controlled for the most important confounding variables. Of the evaluated studies, 13 showed a significant positive association between omega-3 and depression, while six studies did not show a relationship between the referred variables. Therefore, future studies with similar methodology would aid in determining the precise effect of omega-3 on depressive disorders.

Fish and n-3 polyunsaturated fatty acid intake and depressive symptoms: Ryukyus Child Health Study

BACKGROUND

Epidemiologic evidence on the role of fish and long-chain n-3 polyunsaturated fatty acid intake on depression during adolescence is sparse.

OBJECTIVE

We examined the association between fish, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) intake and depressive symptoms in a group of adolescents.

SUBJECTS AND METHOD

This cross-sectional study, conducted in all public junior high schools in Naha City and Nago City, Okinawa, Japan, included 3067 boys and 3450 girls aged 12 to 15 years (52.3% of the eligible sample). Dietary intake was assessed by using a validated, self-administered diet-history questionnaire. Depressive symptoms were defined as present when participants had a Center for Epidemiologic Studies Depression scale score of >or=16.

RESULTS

The prevalence of depressive symptoms was 22.5% for boys and 31.2% for girls. For boys, fish intake was inversely associated with depressive symptoms (adjusted odds ratio [OR] for depressive symptoms in the highest [compared with the lowest] quintile of intake: 0.73 [95% confidence interval (CI): 0.55-0.97]; P for trend=.04). EPA intake showed an inverse association with depressive symptoms (OR: 0.71 [95% CI: 0.54-0.94]; P=.04). DHA intake also showed a similar inverse, albeit nonsignificant, association (OR: 0.79 [95% CI: 0.59-1.05]; P=.11). In addition, intake of EPA plus DHA was inversely associated with depressive symptoms (OR: 0.72 [95% CI: 0.55-0.96]; P=.08). Conversely, no such associations were observed among girls.

CONCLUSIONS

Higher intake of fish, EPA, and DHA was independently associated with a lower prevalence of depressive symptoms in early male, but not female, adolescents.

Dopamine receptor alterations in female rats with diet-induced decreased brain docosahexaenoic acid (DHA): interactions with reproductive status

Decreased tissue levels of n-3 (omega-3) fatty acids, particularly docosahexaenoic acid (DHA), are implicated in the etiologies of non-puerperal and postpartum depression. This study examined the effects of a diet-induced loss of brain DHA content and concurrent reproductive status on dopaminergic parameters in adult female Long-Evans rats. An alpha-linolenic acid-deficient diet and breeding protocols were used to produce virgin and parous female rats with cortical phospholipid DHA levels 20-22% lower than those fed a control diet containing adequate alpha-linolenic acid. Decreased brain DHA produced a significant main effect of decreased density of ventral striatal D(2)-like receptors. Virgin females with decreased DHA also exhibited higher density of D(1)-like receptors in the caudate nucleus than virgin females with normal DHA. These receptor alterations are similar to those found in several rodent models of depression, and are consistent with the proposed hypodopaminergic basis for anhedonia and motivational deficits in depression.

Eating ourselves to death (and despair): the contribution of adiposity and inflammation to depression

Obesity and related metabolic conditions are of epidemic proportions in most of the world, affecting both adults and children. The accumulation of lipids in the body in the form of white adipose tissue in the abdomen is now known to activate innate immune mechanisms. Lipid accumulation causes adipocytes to directly secrete the cytokines interleukin (IL) 6 and tumor necrosis factor alpha (TNFalpha), but also monocyte chemoattractant protein 1 (MCP-1), which results in the accumulation of leukocytes in fat tissue. This sets up a chronic inflammatory state which is known to mediate the association between obesity and conditions such as cardiovascular disease, type 2 diabetes, and cancer. There is also a substantial literature linking inflammation with risk for depression. This includes the observations that: (1) people with inflammatory diseases such as multiple sclerosis, cardiovascular disease, and psoriasis have elevated rates of depression; (2) many people administered inflammatory cytokines such as interferon alpha develop depression that is indistinguishable from depression in non-medically ill populations; (3) a significant proportion of depressed persons show upregulation of inflammatory factors such as IL-6, C-reactive protein, and TNFalpha; (4) inflammatory cytokines can interact with virtually every pathophysiologic domain relevant to depression, including neurotransmitter metabolism, neuroendocrine function, and synaptic plasticity. While many factors may contribute to the association between inflammatory mediators and depression, we hypothesize that increased adiposity may be one causal pathway. Mediational analysis suggests a bi-directional association between adiposity and depression, with inflammation possibly playing an intermediary role.

Fish consumption and omega-3 polyunsaturated fatty acids in relation to depressive episodes: a cross-sectional analysis

High fish consumption and omega-3 polyunsaturated fatty acid (PUFA) intake are suggested to benefit mental well-being but the current evidence is conflicting. Our aim was to evaluate whether a higher level of fish consumption, a higher intake of omega-3 PUFAs, and a higher serum concentration of omega-3 PUFAs link to a lower 12-month prevalence of depressive episodes.We used data from the nationwide Health 2000 Survey (n = 5492) and the Fishermen Study on Finnish professional fishermen and their family members (n = 1265). Data were based on questionnaires, interviews, health examinations, and blood samples. Depressive episodes were assessed with the M-CIDI (the Munich version of the Composite International Diagnostic Interview) and a self-report of two CIDI probe questions, respectively. Fish consumption was measured by a food frequency questionnaire (g/day) and independent frequency questions (times/month). Dietary intake (g/day) and serum concentrations (% from fatty acids) of PUFAs were determined. Fish consumption was associated with prevalence of depressive episodes in men but not in women. The prevalence of depressive episodes decreased from 9% to 5% across the quartiles of fish consumption (g/day) in men of the Health 2000 Survey (p for linear trend = 0.01), and from17% to 3% across the quartiles of fish consumption (times/month) in men of the Fishermen Study (p for linear trend = 0.05). This association was modified by lifestyle; in the Health 2000 Survey a higher level of fish consumption was related to a lower prevalence of depressive episodes in men who consumed the most alcohol, were occasional or former smokers, or had intermediate physical activity. The associations between depressive episodes and the intake or serum concentrations of omega-3 PUFAs were not consistent.In men, fish consumption appears as a surrogate for underlying but unidentified lifestyle factors that protect against depression.

Association of n-3 long-chain PUFA and fish intake with depressive symptoms and low dispositional optimism in older subjects with a history of myocardial infarction

Individuals with CHD are at increased risk of poor mental well-being. Dietary intake of EPA and DHA, the main n-3 fatty acids from fish, may be beneficial to mental well-being. We examined the association of EPA+DHA and fish intake with mental well-being in 644 participants, aged 60–80 years, with a history of myocardial infarction. Habitual food intake was assessed with a 203-item FFQ. Depressive symptoms were assessed with the self-report geriatric depression scale, and dispositional optimism was assessed with the revised life orientation test (LOT-R) and a four-item questionnaire (4Q). In Cox-regression models modified for cross-sectional analyses, we adjusted for sex, age, energy intake, BMI, family history of depression, education, marital status, smoking, physical activity and intake of saturated fat, alcohol and fibre. Compared with the lower tertile, subjects in the higher tertile of EPA+DHA intake had a lower prevalence of depressive symptoms, but this association was not statistically significant (prevalence ratio (PR) 0·78; 95 % CI 0·50, 1·22, P-trend 0·27). The higher tertile of EPA+DHA intake was positively associated with dispositional optimism measured with the 4Q (PR 0·69; 95 % CI 0·46, 1·03, P-trend 0·05), but not according to the LOT-R. Fish intake was not related to either depressive symptoms or dispositional optimism. In conclusion, intake of EPA+DHA was positively associated with dispositional optimism assessed with the 4Q, but not with optimism assessed with the LOT-R or with depressive symptoms.