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Mediterranean Diet and Low Inflammatory Index Reduce Depression Risk

9/3/2019 4:46:47 PM
mediterranean dietDepression is a significant problem worldwide, and estimates suggest that only one in 3 cases are effectively treated with conventional therapies. Even with successful treatment, relapse occurs in about half of cases. Dietary patterns have the potential to reduce the risk of depression by interacting with a variety of neurological pathways. Diet influences inflammation, oxidative stress, neuroplasticity, mitochondrial function, and the gut microbiome—all of which interact with pathways that influence depression and mood.

Studies examine diet and depression connection

In an extensive systematic review and meta-analysis, researchers evaluated adherence to healthy dietary patterns in relation to depressive symptoms or clinical depression. The review included 20 longitudinal studies and 21 cross-sectional studies. To be included in the review, articles had to evaluate a comprehensive dietary assessment as an exposure variable and either clinical depression, depressive symptoms, or use of anti-depressive drugs as an outcome variable. Meta-analyses were conducted for each diet type and for each study design.
The majority of studies were conducted with generally healthy participants and in high-income countries. Most studies evaluated depressive symptoms rather than clinical depression as an outcome variable. Longitudinal studies primarily evaluated incident depression as the outcome variable. The quality was assessed to be high in 32 studies and low in 12 studies.

Mediterranean diet shows promise for managing depression

The strongest link between diet and depression was found for the Mediterranean Diet. Based on 4 longitudinal studies, the relative risk for incident depression was 33% lower for the highest adherence to the Mediterranean Diet when compared with the lowest adherence (RR=0.67; 95% CI, 0.55-0.82). There was also a compelling link between the Dietary Inflammatory Index and depression. When compared with the most inflammatory diet, there was a significantly lower risk of depression associated with the least inflammatory diet in both longitudinal and cross-sectional studies (longitudinal overall HR=0.76; 95% CI, 0.63-0.92). Although the association was weaker, there was also an inverse association between the Healthy Eating Index (HEI) and depression.
The diets that were inversely associated with depression shared these characteristics: more fruits, vegetables, and nuts with lower processed meats and trans fats. Alcohol was consumed in moderation. This comprehensive review can serve as compelling evidence to encourage patients at risk of depression to follow a Mediterranean Diet pattern and avoid inflammatory foods. 
Lassale C, Batty GD, Baghdadli A et al. Healthy dietary indices and risk of depressive outcomes: a systematic review and meta-analysis of observational studies. Mol Psychiatry. 2019; 24: 965-986.