Food and Behaviour Research

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Critical Brain Nutrients: Mental Health Harms from Dietary Advice - and Potential Solutions - BOOK HERE

The effects of dietary improvement on symptoms of depression and anxiety

Firth J, Marx W, Dash S, Carney R, Teasdale SB, Solmi M, Stubbs B, Schuch FB, Carvalho AF, Jacka F, Sarris J (2019) Psychosom Med.  2019 Feb.  doi: 10.1097/PSY.0000000000000673. [Epub ahead of print] 

Web URL: Read this and related abstracts on PubMed here



Poor diet can be detrimental to mental health. However, the overall evidence for the effects of dietary interventions on mood and mental well-being has yet to be assessed. We conducted a systematic review and meta-analysis examining effects of dietaryinterventions on symptoms of depression and anxiety.


Major electronic databases were searched through March 2018 for all randomized controlled trials (RCTs) of dietary interventions reporting changes in symptoms of depression and/or anxiety in clinical and non-clinical populations. Random-effects meta-analyses were conducted to determine effect sizes (Hedges' g with 95% confidence intervals) for dietary interventions compared to control conditions. Potential sources of heterogeneity were explored using subgroups and meta-regression analyses.


Sixteen eligible RCTs with outcome data for 45,826 participants were included; the majority of which examined samples with non-clinical depression (N=15 studies).

Nonetheless, dietary interventions significantly reduced depressive symptoms (g=0.275, 95% C.I.=0.10-0.45, p=0.002). Similar effects were observed among high-quality trials (g=0.321, 95% C.I.=0.12-0.53, p=0.002), and when compared to both inactive (g=0.308, 95% C.I.=0.02-0.60, p=0.038) and active controls (g=0.174, 95% C.I.=0.01-0.34, p=0.035).

No effect of dietaryinterventions was observed for anxiety (k=11, n=2,270, g=0.100, 95% C.I.=-0.04-0.24, p=0.148). Studies with female samples observed significantly greater benefits from dietary interventions, for symptoms of both depression and anxiety.


Dietary interventions hold promise as a novel intervention for reducing symptoms of depression across the population. Future research is required to determine the specific components of dietary interventions that improve mental health, explore underlying mechanisms, and establish effective schemes for delivering these interventions in clinical and public health settings.

This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.


This systematic review included randomised controlled trials of a range of different dietary interventions (albeit all generally aimed at encouraging healtheir eating) on symptoms of depression, anxiety or both.

The trials included involved both clinical and non-clinical samples.

Results showed significant benefits for dietary vs placebo intervention for reducing depressive symptoms, but not anxiety.

This study adds important evidence in support of dietary and nutritonal approaches to the management of mental health problems - and also helps clarify where additional research is still needed.

These positive findings for an impact of dietary changes on depressive symptons - of either clinical or non-clinical severity - suggests that even the existing evidence (limited though this may be) is sufficient for interested clinicians to be able to offer alternative but evidence-based treatment options to the many patients with depressive symptoms for whom existing treatments may be unsuitable or ineffective. 

See the associated news article:

See also the following trials (involving patients diagnosed with clinical depression):

For further information on this topic please see: