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Mediterranean diet may help protect against depression
Adherence to a healthy diet, particularly the Mediterranean diet, or a diet that avoids pro-inflammatory foods may lower the risk for depression, according to findings from a systematic review and meta-analysis of observational studies published in Molecular Psychiatry.
“Despite significant developments, conventional treatment is effective only in one in three cases of mood disorder,” Camille Lassale, PhD, from the department of behavioral science and health, University College London, and colleagues wrote. “The neurological pathways potentially affecting depression risk that can be modulated by nutritional intake are related to inflammation, oxidative stress, neuroplasticity, mitochondrial function, and the gut microbiome.”
The investigators searched clinical databases for studies that assessed whether adhering to dietary guidelines or traditional dietary patterns was tied to depressive symptoms or depression, then pooled estimates using random effect meta-analysis stratified by observational study design and dietary score.
Researchers included 20 longitudinal and 21 cross-sectional studies in their meta-analysis, which measured adherence to the Mediterranean diet, the Healthy Eating Index (HEI) and Alternative HEI, the Dietary Approaches to Stop Hypertension (DASH) and the Dietary Inflammatory Index.
Results from longitudinal studies robustly support a connection between both higher adherence to a Mediterranean diet and lower adherence to a pro-inflammatory diet with a lower risk for depression (RR = 0.67; 95% CI, 0.55-0.82), the researchers reported. A smaller number of studies reporting adherence to dietary guidelines in relation to other chronic diseases and mortality, HEI and Alternative HEI, also revealed the same trend.
The results showed a consistent relationship between an inflammatory diet and incident depressive outcomes. Studies supporting an anti-inflammatory diet showed common elements on dietary scores, such as: higher fruit, vegetable, and nut intake; lower processed meat and trans-fat intake and moderate alcohol consumption.
According to data from four longitudinal studies, Lassale and colleagues found that a lower Dietary Inflammatory Index was tied to reduced depression incidence (RR = 0.76; 95% CI, 0.63-0.92). Although fewer longitudinal studies used other indices, findings from this research and cross-sectional research also indicate an inverse connection between healthy diet and depression (RR = 0.65; 95%, CI 0.50.84 for HEI/Alternative HEI).
“That the majority of recovered studies were cross-sectional in design, with the problem of reverse causality being acute in the context of diet and depression, there is a clear need for more prospective studies,” the researchers wrote. “Moreover, while recent intervention studies provide preliminary evidence, further well-powered clinical trials are required to assess the role of dietary patterns in the prevention of onset, severity, and recurrence of depressive episodes.” – by Savannah Demko
Disclosure: The authors report no relevant financial disclosures.