Serum short chain fatty acids mediate hippocampal BDNF and correlate with decreasing neuroinflammation following high pectin fiber diet in mice

Jamie S Church; Jane A M Bannish; Leighelle A Adrian; Kimberly Rojas Martinez; Asari Henshaw; Jared J Schwartzer

doi:10.3389/fnins.2023.1134080

Serum short chain fatty acids mediate hippocampal BDNF and correlate with decreasing neuroinflammation following high pectin fiber diet in mice

Front Neurosci. 2023 Apr 11:17:1134080. doi: 10.3389/fnins.2023.1134080. eCollection 2023.

Authors

Jamie S Church¹, Jane A M Bannish¹, Leighelle A Adrian¹, Kimberly Rojas Martinez¹, Asari Henshaw¹, Jared J Schwartzer¹

Affiliation

¹ Program in Neuroscience and Behavior, Department of Psychology and Education, Mount Holyoke College, South Hadley, MA, United States.

Abstract

Introduction: Dietary components, such as prebiotic fiber, are known to impact brain chemistry via the gut-brain axis. In particular, short chain fatty acids (SCFAs) generated from excessive soluble fiber consumption are thought to impact neuroimmune signaling and brain function through increased production of neurotropic factors. Given reports that high dietary fiber intake is associated with increased mental health and improved quality of life scores, we set out to identify whether changes in SCFA levels as a result of a high soluble fiber diet mediate hippocampal neuroinflammation and brain derived neurotrophic factor (BDNF) in mice.

Methods: Adult male and female C57BL/6 mice were fed a 1-month high pectin fiber or cellulose-based control diet. Following 1 month of excessive pectin consumption, serum SCFAs were measured using gas chromatography-mass spectrometry (GC-MS) and hippocampal cytokines and BDNF were assessed via multiplex magnetic bead immunoassay.

Results: Pectin-based fiber diet increased circulating acetic acid in both sexes, with no effect on propionic or butyric acid. In the hippocampus, a high fiber diet decreased TNFa, IL-1ß, IL-6, and IFNγ and increased BDNF levels. Furthermore, increased SCFA levels were inversely correlated with neuroinflammation in the hippocampus, with acetic acid revealed as a strong mediator of increased BDNF production.

Conclusion: Collectively, these findings highlight the beneficial effects of fiber-induced molecular changes in a brain region known to influence mood- and cognition-related behaviors. Dietary composition should be considered when developing mental health management plans for men and women with an emphasis on increasing soluble fiber intake.

Keywords: BDNF; SCFAs; cytokines; diet; hippocampus; pectin fiber.

Grants and funding

Mass spectral data were obtained at the University of Massachusetts Mass Spectrometry Core Facility, RRID:SCR_019063 by Dr. Steven Eyles. Funding for this project was provided by the National Institutes of Health R15MH119500 (JS), a Faculty Research Support Grant from Mount Holyoke College (JC), the Harap Scholarship Fund for Student Research (KR and AH), and Evans Vorwerk Psychology Research Fund (LA).