A recent meta-analysis of past studies seeks to understand the relationship between meat consumption and risk of depression.
The prevalence of depression rises globally year after year. The World Health Organization (WHO) indicates that over 350 million people suffer from depression worldwide. With such a ubiquitous mental health issue, Chinese researchers sought to analyze past observational studies to examine the effect of diet on depression and mental state. More specifically, the researchers examined the relationship between meat consumption and depression.
Observational studies were gathered from both PUBMED and EMBASE electronic databases to include results up to March 2017. They included eight observational studies in this meta-analysis that met the following criteria: studies must have been observational in structure (case-control, cohort, or cross-sectional), the exposure variable of interest was meat consumption, and the outcome of the variable of interest was the odds ratio (OR) and relative risk (RR) relating to depression. Studies excluded from the search were duplicated articles, reviews, letters, or case reports, and non-human studies.
The eight studies selected for the analysis that was published in BMC Psychiatry came from mainly Australian and Asian countries, along with one study from Spain. Six studies focused on the odds ratio of the prevalence of depression in regards to the highest versus lowest meat consumption category while the remaining two studies focused on the relative risk of depression for the highest versus the lowest meat consumption category.
Eating Meat May be Linked to Depression
The quantitative observations showed that meat consumption may be related to a moderately higher risk of depression but when compared to the overall prevalence of depression, no significant relationship could be observed.
Notably, the studies did not differentiate between meat varieties, and as such red and white meat was regarded as a singular data point; future studies should examine if there are any differences between meat types such as red, white, processed, or organic. Additionally, overall risks of depression are variable due to the cyclic nature of depressive states. The results show that meat consumption might be associated with a higher risk of depression. Consequently, depressive subjects have been noted to have reduced appetite and would, therefore, consume less meat, hence no significant relationship would be observed according to the analysis.
While this study was the first of its kind and set a foundation for future analyses, it was limited in the amount of literature available for data comparisons. The current theory postulates that meat consumption may be associated with a moderately higher risk of depression but further research is required to confirm these results.
Written by Cooper Powers, BSc
Reference: Zhang, Y., Yang, Y., Ming-Sheng, X., Xiang, D., Hui, L., Zhi-chen, L., Peng, S. (2017). Is meat consumption associated with depression? A meta-analysis of observational studies. BMC Psychiatry, 17(409). DOI 10.1186/s12888-017-1540-7.