Association of a priori dietary patterns with depressive symptoms: a harmonised meta-analysis of observational studies.

BACKGROUND: Review findings on the role of dietary patterns in preventing depression are inconsistent, possibly due to variation in assessment of dietary exposure and depression. We studied the association between dietary patterns and depressive symptoms in six population-based cohorts and meta-analysed the findings using a standardised approach that defined dietary exposure, depression assessment and covariates. METHODS: Included were cross-sectional data from 23 026 participants in six cohorts: InCHIANTI (Italy), LASA, NESDA, HELIUS (the Netherlands), ALSWH (Australia) and Whitehall II (UK). Analysis of incidence was based on three cohorts with repeated measures of depressive symptoms at 5-6 years of follow-up in 10 721 participants: Whitehall II, InCHIANTI, ALSWH. Three a priori dietary patterns, Mediterranean diet score (MDS), Alternative Healthy Eating Index (AHEI-2010), and the Dietary Approaches to Stop Hypertension (DASH) diet were investigated in relation to depressive symptoms. Analyses at the cohort-level adjusted for a fixed set of confounders, meta-analysis used a random-effects model. RESULTS: Cross-sectional and prospective analyses showed statistically significant inverse associations of the three dietary patterns with depressive symptoms (continuous and dichotomous). In cross-sectional analysis, the association of diet with depressive symptoms using a cut-off yielded an adjusted OR of 0.87 (95% confidence interval 0.84-0.91) for MDS, 0.93 (0.88-0.98) for AHEI-2010, and 0.94 (0.87-1.01) for DASH. Similar associations were observed prospectively: 0.88 (0.80-0.96) for MDS; 0.95 (0.84-1.06) for AHEI-2010; 0.90 (0.84-0.97) for DASH. CONCLUSION: Population-scale observational evidence indicates that adults following a healthy dietary pattern have fewer depressive symptoms and lower risk of developing depressive symptoms.

Surplus vitamin B12 use does not reduce fatigue in patients with Irritable Bowel Syndrome or inflammatory bowel disease: A randomized double-blind placebo-controlled trial.

OBJECTIVE: In non-conventional care, high doses of vitamin B12 supplementation are used for the treatment of fatigue even in case of normal vitamin B12 blood levels. We performed a randomized placebo controlled trial to investigate the effect of surplus oral vitamin B12 supplementation on fatigue in patients with IBS or IBD. METHODS: This randomized double-blind, placebo-controlled trial included 95 out-clinic IBS and IBD patients with deactivating fatigue and normal vitamin B12 blood levels (≥150 pmol/l) aged 18-65 years. Participants were randomly assigned to receive 1000 µg vitamin B12 daily or a placebo supplement for 8 weeks. The primary outcome measure was fatigue (Checklist Individual Strength (CIS)). In addition, measures of quality of life and depression were examined. RESULTS: No significant difference in scores of the CIS subscale 'subjective fatigue' was observed between the intervention group and the control group with changes in scores of -8.1 ± 9.5 and -8.3 ± 10.6 (95% CI -11.65 to 6.71), respectively. The scores on the CIS subscale 'motivation' improved with a significant change in scores of -2.2 ± 4.6 (95% CI -4.4 to -0.04). No significantly increased scores were observed for depression or quality of life in the intervention group compared to the control group. CONCLUSION: This study did not confirm the expected effect of non-conventional surplus vit B12 supplementation on fatigue in IBS or IBD patients. In addition, no positive effect was observed on depression or quality of life. We conclude that surplus treatment with vitamin B12 in IBS and IBD patients suffering from fatigue has no beneficial clinical effect.