Relationships among diet, the gastrointestinal microbiota, and mood
Nearly 5% of the global population are burdened with depression and nearly 7% have an anxiety disorder. Adequate nutrient intake is paramount to human health, helping maintain homeostasis of physiological systems, and maintaining or modulating the gastrointestinal microbiota. Cross-sectional and preclinical studies have demonstrated improvements to mental health following dietary interventions, but there is a dearth of evidence from clinical intervention trials to support dietary interventions strategies to treat the symptoms of depression, anxiety, or stress. In addition to diet, the gastrointestinal (GI) microbiota has also been associated with mood disorders. However, additional studies are needed to confirm if diet and/or the GI microbiota relate to changes in mood among adults. The objective of this research was to investigate links among diet, GI microbiota, and the negative emotional states of depression, anxiety, and stress. The review of literature revealed that the relationships between mood and GI microbiota is under investigated in populations without physician diagnosed mood disorders, diet is rarely measured or controlled for in research trials assessing connections between the GI microbiota and mood, and dietary and microbial connections to mood are typically studied independently, rather than together. Accordingly, a cross-sectional study in adults representative of the general public was undertaken to test the hypotheses that GI microbiota and diet are associated with the negative emotional states of depression, anxiety, and stress in adults without physician diagnosed mood disorders. Diet history questionnaires were utilized to assess habitual diet and fecal samples were analyzed to characterize the GI microbiota of participants. Mood was assessed using the Depression, Anxiety, and Stress Scale (DASS), which consists of three scales that measure the negative emotional states of depression, anxiety, and stress experienced within the past week. These DASS score variables were assessed in relation to dietary components, diet quality, and bacterial relative abundances. Additionally, relations between DASS scores and bacterial relative abundances were assessed with and without dietary fiber in the statistical model. The analyses revealed relationships supported by existing literature and that relationships between mood and GI microbiota may be influenced by sex and dietary fiber intake. They also revealed that mood is associated with adequate fruit intake. Herein, we review the current literature and present novel findings from our original research. The results revealed associations among diet, the GI microbiota, and negative emotional states. Further study is warranted to determine if synergistic diet-microbiota therapies can be undertaken to prevent or treat symptoms of depression, anxiety, and stress.
Gut Microbiome, Mental Health, Gut-Brain Axis
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign