Serum polyunsaturated fatty acids are not associated with the risk of severe depression in middle-aged Finnish men: Kuopio Ischaemic Heart Disease Risk Factor (KIHD) study

Effect of High Ratio of n-6/n-3 PUFAs on Depression: A Meta-Analysis of Prospective Studies

Objective

The aim of this systematic review and meta-analysis was to examine the association between high ratio of n-6/n-3 polyunsaturated fatty acids (PUFAs) and depression.

Methods

The authors conducted a meta-analysis of research articles on the association of high ratio of n-6/n-3 PUFAs with the risk of depression published in the online article database on PubMed, Embase, Cochrane library as of December 2021. Pooled odds ratios (OR) were calculated using random effects models. Publication bias was assessed visually by funnel plots and statistically by the Egger’s and Begg’s tests.

Results

Finally, 12 studies included in this systematic review and meta-analysis with a total of 66,317 participants (including 4,173 individuals with depression condition). The pooled results showed that high ratio of n-6/n-3 PUFAs might be positively associated with depression [OR = 1.21, 95% confidence intervals (CIs): 1.04∼1.41]. The I² test indicated that there was a substantial statistical heterogeneity across the included studies (I² = 54.38%, P = 0.01). Subgroup analysis showed that high ratio of n-6/n-3 PUFAs in blood had no significant association with depression (OR = 1.15, 95%CI: 0.88∼1.50), while high ratio of n-6/n-3 PUFAs in dietary supplements was positively associated with depression (OR = 1.32, 95%CI: 1.16∼1.51).

Conclusion

This meta-analysis confirmed the association between high ratio of n-6/n-3 PUFAs and the risk of depression. High ratio of n-6/n-3 PUFAs in dietary supplementation was positively associated with depression, but had no significant association in the blood. This study suggested that lowering the dietary intake of the ratio of n-6/n-3 PUFAs would be beneficial in the prevention of depression.

Association between erythrocyte levels of n-3 polyunsaturated fatty acids and depression in postmenopausal women using or not using hormone therapy

OBJECTIVE

Epidemiologic and clinical studies have suggested that hormone therapy (HT) and n-3 polyunsaturated fatty acids (PUFAs), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), exert antidepressant effects through regulation of the serotonergic pathway. The present study was conducted to evaluate the hypothesis that erythrocyte levels of n-3 PUFAs and depression were negatively associated in postmenopausal women, particularly those using HT.

METHODS

A total of 214 postmenopausal women were divided into groups defined by depression and HT status. Depression was defined as a Beck Depression Inventory score of at least 14, and the types and durations of HT were obtained from medical records.

RESULTS

Erythrocyte levels of EPA, docosapentaenoic acid (DPA), DHA, omega-3 index (sum of EPA + DHA), total n-3 PUFA, and arachidonic acid were significantly higher in women using HT than in those not using HT. There were significant negative correlations between depression and erythrocyte levels of alpha-linolenic acid (r = -0.310), DPA (r = -0.272), DHA (r = -0.209), and total n-3 PUFA (r = -0.234) in women using HT. Multivariate-adjusted logistic regression analysis also showed that depression was negatively associated with the erythrocyte levels of alpha-linolenic acid (P for trend = 0.018), DPA (P for trend = 0.014), and DHA (P for trend = 0.036), only in women using HT.

CONCLUSIONS

Negative associations between erythrocyte levels of n-3 PUFAs and depression were found in Korean postmenopausal women using HT but not in those not using HT, suggesting a synergistic effect of HT and n-3 PUFAs on depression.

Serum dihomo-γ-linolenic acid level is inversely associated with the risk of depression. A 21-year follow-up study in general population men

BACKGROUND

Depression is a major public health challenge worldwide, and polyunsaturated fatty acids (PUFAs), especially n-3 PUFAs, have been found to inversely associate with the risk of depression. However, only few cross-sectional studies have investigated the association between dihomo-γ-linolenic acid (DGLA), an n-6 PUFA with anti-inflammatory effects, and depression. The aims of the present study were to examine an association between serum DGLA and the risk of depression, and to study whether the potential association is mediated via inflammation.

METHODS

A 20-year prospective Kuopio Ischaemic Heart Disease Risk Factor (KIHD) follow-up study was conducted from 1984 to 1989 with 2179 middle-aged and older Finnish men (42-60 years old at baseline). The baseline concentrations of serum fatty acids, including DGLA, were determined. A hospital discharge diagnosis of depression was used as the main outcome and obtained from linkage to National Hospital Discharge Register. Serum C-reactive protein (CRP) levels were measured to assess inflammation.

RESULTS

An inverse association between serum DGLA concentration and incidence of depression was found after adjustment for several potential confounders (Hazard ratio HR 0.53, CI 0.36-0.79, P=0.002). The association between DGLA and depression was not dependent on inflammation (P-interaction=0.618).

LIMITATIONS

Our findings may not be generalizable to individuals below middle-age or women. Moreover, we were unable to consider cases with mild depression in the longitudinal setting.

CONCLUSIONS

Higher serum DGLA concentrations may predict lower risk of develop depression in elderly men. Further studies are warranted to address potential mechanisms as mechanism behind this association remains unclear.

There is No Association Between the Omega-3 Index and Depressive Symptoms in Patients With Heart Disease Who Are Low Fish Consumers

BACKGROUND

Long chain Omega-3 polyunsaturated fatty acids (LCn3PUFAs) may improve cardiovascular health and depression. This study investigated the relationships between erythrocyte membrane LCn3PUFA status, depression and angina symptoms in patients with heart disease.

METHODS

We recruited 91 patients (65 males and 26 females, mean age 59.2±10.3 years) with heart disease and depressive symptoms (Center for Epidemiological Studies Depression Scale, CES-D ≥ 16) and low fish/fish oil intakes. The Omega-3 Index (EPA+DHA) of erythrocyte membranes (as a percentage of total fatty acids) was assessed by gas chromatography. Depression status was measured by both self-report and clinician-report scales; CES-D and the Hamilton depression scale (HAM-D). Angina symptoms were measured using the Seattle Angina Questionnaire and the Canadian Cardiovascular Society Classification for Angina Pectoris.

RESULTS

The mean Omega-3 Index was 4.8±1.0% (±SD). Depression scores measured by CES-D and HAM-D were 29.2±8.8 (moderate to severe) and 11.0±5.7 (mild) (arbitrary units) respectively reflecting a different perception of depressive symptoms between patients and clinicians. Angina status was inversely associated with depression scores (r>-0.26, P<0.03). There were no significant relationships between individual LCn3PUFA or the Omega-3 Index and either the depression scores or the angina symptoms.

CONCLUSION

Worse angina status was associated with worse depression, but the Omega-3 Index was not associated with symptoms of depression or angina in patients with heart disease.

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

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

Metabolic disturbances connecting obesity and depression

Obesity markedly increases the odds of developing depression. Depressed mood not only impairs motivation, quality of life and overall functioning but also increases the risks of obesity complications. Abdominal obesity is a better predictor of depression and anxiety risk than overall adipose mass. A growing amount of research suggests that metabolic abnormalities stemming from central obesity that lead to metabolic disease may also be responsible for the increased incidence of depression in obesity. As reviewed here, a higher mass of dysfunctional adipose tissue is associated with several metabolic disturbances that are either directly or indirectly implicated in the control of emotions and mood. To better comprehend the development of depression in obesity, this review pulls together select findings addressing the link between adiposity, diet and negative emotional states and discusses the evidence that alterations in glucocorticoids, adipose-derived hormones, insulin and inflammatory signaling that are characteristic of central obesity may be involved.

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.

Marine omega-3 fatty acids and mood disorders--linking the sea and the soul. 'Food for Thought' I

OBJECTIVE

While there has long been interest in any nutritional contribution to the onset and treatment of mood disorders, there has been increasing scientific evaluation of several candidate nutritional and dietary factors in recent years. In this inaugural study of our 'Food for Thought' series, we will overview the evidence for any role of omega-3 fatty acids (FA) in regulating mood.

METHOD

Relevant literature was identified through online database searches and cross-referencing.

RESULTS

Plausible mechanisms exist by which omega-3 FA may influence neuronal function and mood. Cross-sectional studies demonstrate an association between omega-3 fatty acid deficiency and both depressive and bipolar disorders. Studies investigating the efficacy of omega-3 fatty acid supplementation for mood disorders have however provided inconsistent results. The proportion of treatment studies showing a significant advantage of omega-3 supplementation has dropped over the last 5 years. However, the vast heterogeneity of the trials in terms of constituent omega-3 FAs, dose and length of treatment makes comparisons of these studies difficult.

CONCLUSION

More research is required before omega-3 supplementation can be firmly recommended as an effective treatment for mood disorders. Whereas increased omega-3 FA intake may alleviate depressive symptoms, there is little evidence of any benefit for mania.