Associations among diet, the gastrointestinal microbiota, and negative emotional states in adults

ABSTRACT

Objective: Habitual diet impacts mood and the human gastrointestinal (GI) microbiota. Yet, studies infrequently control for diet when evaluating associations between mood and GI microbiota. Accordingly, we aimed to investigate relationships among diet, GI microbiota, and mood in adults without mood disorders by conducting a cross-sectional examination of dietary intake, subjective emotional state, and fecal microbial taxa abundances.

Methods: Adults (N = 133; 25–45 years of age) without physician-diagnosed mood disorders were studied. Fecal DNA was extracted, and the V4 region of the 16S rRNA gene was sequenced. Sequences were analyzed using QIIME2. Subjective mood state was assessed using the 42-item Depression, Anxiety, and Stress Scale (DASS-42). Habitual dietary intake was measured with the National Cancer Institute's Diet History Questionnaire II, and diet quality was evaluated with the 2010 Healthy Eating Index (HEI).

Results: Relationships were observed between 28 bacterial taxa and DASS-42 scores. Sex-dependent associations were observed among 21 bacterial taxa and DASS-42 scores, including an inverse relationship between Anxiety scale scores and Bifidobacterium in females and an inverse relationship between Depression scale scores and Lactobacillus in males. HEI total fruit and dairy components were inversely associated with Depression and Stress scales, respectively.

Conclusions: These results suggest GI microbes are related to mood in adults without diagnosed mood disorders and that these relationships differ by sex and are influenced by dietary fiber intake. Incorporating dietary intake data in gut-microbiota-brain studies may help clarify the roles of specific microbes and dietary components in mental health symptoms.

KEYWORDS:

• Microbiome
• fiber
• diet quality
• depression
• anxiety
• stress
• DASS

Disclosure statement

No potential conflict of interest was reported by the authors.

Ethics approval

University of Illinois Institutional Review Board.

Notes on contributors

Andrew M. Taylor has a B.S. and M.S. in Food Science and Human Nutrition from the University of Illinois at Urbana-Champaign. His research explores the relationships between dietary modulation of the gastrointestinal microbiota and mental health.

Sharon V. Thompson is a registered dietitian with a M.S. in Human Nutrition. She is a third-year predoctoral fellow who is currently investigating the impact of dietary manipulation on body composition and the gut-microbiota-liver axis.

Caitlyn G. Edwards received a B.S. in Nutrition and Dietetics degree with a minor in Psychology from New York University. Caitlyn is a third-year predoctoral student. Her main research interests are the impact of dietary choices on mental health and cognitive functioning. She is currently investigating the interactions between BMI, diet, and cognitive functioning.

Salma M.A. Musaad, Research Biostatistician, has more than 10 years of experience in clinical research, including 1.5 years in ophthalmology and stem-cell research, 4 years in molecular epidemiology in academia, and 4 years in clinical research organizations focusing on clinical trials and public health research. She has extensive expertise in epidemiological study design and conducting field studies, with additional experience in questionnaire development, validation, and testing. In addition, she comes with strong biostatistical experience in statistical consulting and advanced methods, including quantile regression, structural equation modeling, and generalized linear models.

Dr. Naiman A. Khan is an assistant professor in the Department of Kinesiology and Community Health, and a faculty member of the Division of Nutritional Sciences at the University of Illinois. Dr. Khan's research interest is in the area of Nutritional Neuroscience. His laboratory utilizes a multidisciplinary approach to integrate knowledge in the disciplines of dietetics, body composition, and cognitive neuroscience to understand the interactions between lifestyle behaviors (e.g. diet and physical activity), abdominal adiposity, and cognitive and brain health in pediatric and adult populations. The knowledge gained from this work is used to develop effective behavioral or environmental strategies of mitigating the detrimental effects of obesity and metabolic risk on measures of physical and mental health.

Dr. Hannah D. Holscher is an assistant professor of nutrition in the Department of Food Science and Human Nutrition, and a faculty member of the Division of Nutritional Sciences, the Institute of Genomic Biology, and the National Center for Supercomputing Applications at the University of Illinois. Research in Dr. Holscher's laboratory, the Nutrition and Human Microbiome Laboratory, integrates the areas of nutrition, gastrointestinal physiology, and the microbiome. Her research focuses on the clinical application of nutritional sciences with an overarching goal of improving human health through dietary modulation of the gastrointestinal microbiome.

Additional information

Funding

This work was supported by the USDA National Institute of Food and Agriculture, Hatch project under grant number 1009249. Partial support was provided by a grant from the Hass Avocado Board.