EffectsofPolyphenolsinaMediterraneanDieton SymptomsofDepression:ASystematicLiterature Review

Abstract

Depression is a mood disorder which currently affects 350 million individuals worldwide. Recently, research has suggested a protective role of diet for depression. The Mediterranean-style dietary pattern has been highlighted in several systematic reviews as a promising candidate for reducing depressive symptoms. It has been speculated that this could be due to the high polyphenol content of foods commonly found in the diet. Therefore, the aim of this review was to assess the effects of polyphenols found in a Mediterranean diet on the symptoms of depression. A systematic literature review was conducted of original research which assessed the role of polyphenols on the symptoms of depression in humans. The following databases were searched: PROQUEST, SCOPUS (Elsevier), MEDLINE (EBSCO), CINAHL, and EMBase, up to 18 February, 2019. Theinclusioncriteriaconsistedofbothobservationalandexperimentalresearchinadultsaged18–80ythatassesseddepressionscoresinrelationto polyphenolintake.Atotalof37studiesoutof12,084metthefullinclusioncriteria.Ofthese,17wereexperimentalstudiesand20wereobservational studies. Several different polyphenols were assessed including those from tea, coffee, citrus, nuts, soy, grapes, legumes, and spices. Twenty-nine of the studies founda statistically significant effect of polyphenols for depression. This review has foundboth an associationbetween polyphenol consumptionanddepressionrisk,aswellasevidencesuggestingpolyphenolscaneffectivelyalleviatedepressivesymptoms.Thereviewuncovered gaps in the literature regarding the role of polyphenols for depressive symptoms in both young adults and men. This review was registered at www.crd.york.ac.uk/PROSPEROasCRD42019125747