There are so many studies that imply that eating a healthy diet alleviates stress and help a person to think more clearly. But the evidence on diet and how it may alleviate or increase the progression of depression is relatively weaker and there are chances that there is no evidence at all.
Florian Thomas-Odenthal from Leiden University tried to unveil this relation as a part of her Masters’s research. The complete findings of this study are now published in the journal PLOS ONE.
A healthy diet makes a person stress free. Mediterranean diet is the best diet to prevent depression. Statements like these are common and more common when a person is trying to lose weight and frustration attached to obesity.
In recent years, following a more ‘natural’ approach for dealing with common life problems has become fairly common which is why certain types of diet have become a ‘trend. While this field is still less explored in terms of research, many research institutes are trying to explore the truth behind these so-called healthy or weight loss diets.
Going through a number of studies that reveal a link between diet and depression, Florian Thomas-Odenthal along with Marc Molendijk, her supervisor and Willem van der Does and Patricio Molero, two co-authors of this study came to a surprising conclusion. They found that in almost all these studies, the research team-built conclusions that were stronger than the evidence that could justify these results.
Together, this team overlooked 50 studies including narrative, systemic studies, and meta-analyses. Choosing three different approaches to study the same thing was to make sure that there is no aspect of leaving any information behind. A literature review is generally an opinionated review by the author where he draws a conclusion based on studies and articles by himself.
A systemic study or review follows a standard protocol to identify the sources, analyzing the information, and building the conclusion. Lastly, the meta-analysis is a type of study that has strict controlling agents and it provides a complete statistical overview of the facts covered by the existing research.
Nearly 1/3rd of the literature reviews suggest that there is a strong link between diet and depression. But not a single meta-analyzes was able to figure it out. In addition to this, Thomas-Odenthal organized and conducted an individual meta-analysis taking the experimental evidence altogether and trying to understand the link between diet and the onset of depression and how it may be able to treat depression. All in all, there was no link established.
About the evidence shown from the literature review, Thomas-Odenthal says that this type of review normally contains lesser studies and an indirect approach to form an analysis. Also, it is the author who picks the studies so the chance of imbalance remains there. It is also possible for an author to support his own research instead of presenting the true picture. Because of this confirmation biases, it is possible that results built on literature reviews are too rigid.
In the case of systematic reviews and meta-analyses, this risk of biases is minimum because the researcher has to follow a standard pattern. Therefore, the risk of the conclusion being too rigid is least here.