Demonstrating a link between diet, gut microbiota and brain: C radioactivity identified in the brain following gut microbial fermentation of C-radiolabeled tyrosine in a pig model.

Journal: Frontiers in nutrition

Volume: 10

Issue: 

Year of Publication: 

Affiliated Institutions:  School of Chemistry, Monash University, Clayton, VIC, Australia. Monash Proteomics and Metabolomics Facility and Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia. Fraunhofer Institute for Molecular Biology and Applied Ecology, Schmallenberg, Germany. Monash Animal Research Platform, Monash University, Churchill, VIC, Australia. School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia. Department of Nutrition, Dietetics and Food, Monash University, Notting Hill, VIC, Australia.

Abstract summary 

There is a need to better understand the relationship between the diet, the gut microbiota and mental health. Metabolites produced when the human gut microbiota metabolize amino acids may enter the bloodstream and have systemic effects. We hypothesize that fermentation of amino acids by a resistant protein-primed gut microbiota could yield potentially toxic metabolites and disturb the availability of neurotransmitter precursors to the brain. However, these mechanisms are challenging to investigate typical and clinical methods.We developed a novel workflow using C radiolabeling to investigate complex nutrient-disease relationships. The first three steps of the workflow are reported here. α-Linolenic acid (ALA) was used as a model nutrient to confirm the efficacy of the workflow, and tyrosine (Tyr) was the test nutrient. C-Tyr was administered to male weanling pigs fed a high resistant protein diet, which primed the gut microbiota for fermenting protein. The hypotheses were; (1) that expected biodistribution of C-ALA would be observed, and (2) that radioactivity from C-Tyr, representing Tyr and other amino acids released from resistant protein following gut microbial fermentation, would be bioavailable to the brain.Radioactivity from the C-ALA was detected in tissues reflecting normal utilization of this essential fatty acid. Radioactivity from the C-Tyr was detected in the brain (0.15% of original dose).Metabolites of gut-fermented protein and specifically amino acid precursors to neurotransmitters such as tyrosine, are potentially able to affect brain function. By extension, resistant proteins in the diet reaching the gut microbiota, also have potential to release metabolites that can potentially affect brain function. The high specificity of detection of C radioactivity demonstrates that the proposed workflow can similarly be applied to understand other key diet and health paradigms.

Authors & Co-authors:  Murray Margaret M Barlow Christopher K CK Blundell Scott S Buecking Mark M Gibbon Anne A Goeckener Bernd B Kaminskas Lisa M LM Leitner Patricia P Selby-Pham Sophie S Sinclair Andrew A Waktola Habtewold D HD Williamson Gary G Bennett Louise E LE

Study Outcome 

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Statistics
Citations :  van Kleef E, van Trijp HCM, Luning P. Functional foods: health claim-food product compatibility and the impact of health claim framing on consumer evaluation. Appetite. (2005) 44:299–308. 10.1016/j.appet.2005.01.009
Authors :  13
Identifiers
Doi : 1127729
SSN : 2296-861X
Study Population
Male
Mesh Terms
Other Terms
biodistribution;carbon-14 radio-isotope;gut-brain axis;resistant protein;tyrosine;α-linolenic acid
Study Design
Cross Sectional Study
Study Approach
Systemic Review
Country of Study
Publication Country
Switzerland