A new probe of countless published articles targeting nutritional interventions for depressive symptoms uncovered no evidence to validate prior studies of its beneficial potential.
As released in the journal PLOS ONE, Florian Thomas-Odenthal and co-authors at Leiden University conducted systematic searches using databases such as Google Scholar, Web of Science, and PubMed.
The wealth of articles they examined included 24 narrative reviews, 12 systematic reviews, and 14 meta-analyzes. According to the co-authors, the narrative with regards to the findings of each article varied based on the approach used.
For instance, literature reviews, the co-authors inferred, generally led to stronger conclusory statements on the association between diet and improvement in depressive symptoms, while meta-analyzes could not establish with such level of confidence.
“We saw that, on average, literature reviews contain 45% fewer studies as a source than meta-analyzes. Furthermore, if the author selects the sources, it is easy for an imbalance can creep in,” said Thomas-Odenthal in a news release.
“We have shown that narrative reviews come to stronger conclusions about the benefits of a healthy diet on depression despite inconclusive evidence. This finding empirically underscores the importance of a systematic method for summarizing the evidence of a field of study,” Thomas-Odenthal concluded.
“Journal editors may want to reconsider publishing narrative reviews before meta-analytic reviews are available.”