Fiber intake and fiber intervention in depression and anxiety: a systematic review and meta-analysis of observational studies and randomized controlled trials Original paper

What was reviewed?

This paper conducted a systematic review and meta-analysis focusing on fiber intake and its interventions in the context of depression and anxiety. It examined observational studies and randomized controlled trials (RCTs) to evaluate the effects of fiber consumption on mental health outcomes, specifically depressive and anxiety symptoms. The review synthesized data from various clinical trials and cohort studies to determine the relationship between fiber and mental well-being, with a focus on its potential therapeutic effects.

Who was reviewed?

The review focused on individuals participating in observational studies and randomized controlled trials related to dietary fiber intake. These participants were from diverse populations, including healthy adults, individuals with moderate psychological distress, and those with clinical conditions such as diabetes or cardiovascular diseases. The studies reviewed included various age groups and socio-demographic backgrounds, primarily adults aged 18-65 years, with a significant portion of studies also featuring female participants.

What were the most important findings?

The review revealed a modest yet significant association between fiber intake and improvements in depressive and anxiety symptoms. Specifically, the results from observational studies suggested that higher fiber intake, particularly from prebiotic-rich foods, was linked to better mood and reduced anxiety. However, the findings from RCTs were less conclusive, with fiber supplementation showing minimal benefits for improving depression and anxiety in the general population. Notably, certain prebiotics such as galactooligosaccharides (GOS) exhibited potential benefits for reducing anxiety. The review also emphasized that while fiber intake might reduce inflammation and improve gut health, the mechanisms underlying these effects remain complex and require further exploration.

What are the greatest implications of this study/review?

The greatest implication of this review is the potential role of dietary fiber, particularly prebiotics, as an adjunctive treatment for managing depression and anxiety, especially in populations with lower fiber intake. The findings suggest that simple dietary interventions, such as increasing fiber intake from whole foods, could be a cost-effective and accessible approach to support mental health, particularly for individuals experiencing mild psychological distress. However, the review also highlighted the need for more robust, larger-scale RCTs to confirm the efficacy of fiber interventions in clinical populations, and to clarify the mechanisms by which fiber impacts mental health.