Diet overall and hypocaloric diets are associated with improvements in depression but not anxiety in people with metabolic conditions: A systematic review and meta-analysis.

The risk of depression and anxiety are higher in people with metabolic conditions, but whether dietary approaches which are central to the management of metabolic conditions, can also improve depression and anxiety is uncertain. The primary aim of this systematic review and meta-analysis was to evaluate the effects of dietary interventions on depression and anxiety in adults with metabolic conditions. The secondary aims were to evaluate the effects of hypocaloric and isocaloric dietary interventions on these outcomes. Four databases (MEDLINE, PsychINFO, EMBASE and CINAHL) were searched from inception to March 2023. Randomised controlled trials (RCTs) including dietary interventions in adults with metabolic conditions [type 2 diabetes mellitus (T2DM), hyperlipidaemia, hypertension, and/or overweight/obesity] that assessed depression and/or anxiety as outcomes were included. Overall, 13 RCTs were included in the systematic review and up to 13 of which were included in the meta-analysis. Estimates were pooled using random effect meta-analysis for dietary interventions compared with controls. Improvements in depression scores were found in meta-analytic models including all dietary interventions [pooled estimate for the standardized mean difference (SMD)=-0.20 (95% confidence interval (CI), -0.35 to -0.05), probability (p)=0.007] and hypocaloric only diets [SMD=-0.27 (95%CI, -0.44 to -0.10), p=0.002]. There were no improvements in depression scores with isocaloric dietary interventions only [SMD=-0.14 (95% CI -0.38 to 0.10), p=0.27]. In addition, there were no significant effects for any dietary interventions on anxiety scores. In adults with metabolic conditions, all dietary interventions and hypocaloric diets improved depression, but not anxiety. These findings suggest that dietary interventions including hypocaloric diets can play an important role in the management of depression in people with metabolic conditions. This systematic review and meta-analysis has been registered with PROSPERO (CRD42021252307).