The Impact of a 24-h Low and High Fermentable Oligo- Di- Mono-Saccharides and Polyol (FODMAP) Diet on Plasma Bacterial Profile in Response to Exertional-Heat Stress

Stephanie K Gaskell; Kayla Henningsen; Pascale Young; Paul Gill; Jane Muir; Rebekah Henry; Ricardo J S Costa

doi:10.3390/nu15153376

The Impact of a 24-h Low and High Fermentable Oligo- Di- Mono-Saccharides and Polyol (FODMAP) Diet on Plasma Bacterial Profile in Response to Exertional-Heat Stress

Nutrients. 2023 Jul 29;15(15):3376. doi: 10.3390/nu15153376.

Authors

Stephanie K Gaskell¹, Kayla Henningsen¹, Pascale Young¹, Paul Gill², Jane Muir², Rebekah Henry^{3

4}, Ricardo J S Costa¹

Affiliations

¹ Department of Nutrition Dietetics & Food, Monash University, Notting Hill, VIC 3168, Australia.
² Department of Gastroenterology, Monash University, Melbourne, VIC 3004, Australia.
³ School of Public Health and Preventive Medicine, Monash University, Clayton, VIC 3168, Australia.
⁴ Department of Civil Engineering, Monash University, Clayton, VIC 3168, Australia.

Abstract

Exertional-heat stress (EHS) compromises intestinal epithelial integrity, potentially leading to the translocation of pathogenic agents into circulation. This study aimed to explore the impact of EHS on the systemic circulatory bacterial profile and to determine the impact of a short-term low (LFOD) and high (HFOD) fermentable oligo- di- mono-saccharide and polyol dietary intervention before EHS on this profile. Using a double-blind randomized cross-over design, thirteen endurance runners (n = 8 males, n = 5 females), with a history of exercise-associated gastrointestinal symptoms (Ex-GIS), consumed a 24 h LFOD and HFOD before 2 h running at 60% V.O_2max in 35.6 °C. Blood and fecal samples were collected pre-EHS to determine plasma microbial DNA concentration, and sample bacteria and short chain fatty acid (SCFA) profiles by fluorometer quantification, 16S rRNA amplicon gene sequencing, and gas chromatography, respectively. Blood samples were also collected post-EHS to determine changes in plasma bacteria. EHS increased plasma microbial DNA similarly in both FODMAP trials (0.019 ng·μL^-1 to 0.082 ng·μL^-1) (p < 0.01). Similar pre- to post-EHS increases in plasma Proteobacteria (+1.6%) and Firmicutes (+0.6%) phyla relative abundance were observed in both FODMAP trials. This included increases in several Proteobacteria genus (Delftia and Serratia) groups. LFOD presented higher fecal Firmicutes (74%) and lower Bacteroidota (10%) relative abundance pre-EHS, as a result of an increase in Ruminococcaceae and Lachnospiraceae family and respective genus groups, compared with HFOD (64% and 25%, respectively). Pre-EHS plasma total SCFA (p = 0.040) and acetate (p = 0.036) concentrations were higher for HFOD (188 and 178 μmol·L^-1, respectively) vs. LFOD (163 and 153 μmol·L^-1, respectively). Pre-EHS total fecal SCFA concentration (119 and 74 μmol·g^-1; p < 0.001), including acetate (74 and 45 μmol·g^-1; p = 0.001), butyrate (22 and 13 μmol·g^-1; p = 0.002), and propionate (20 and 13 μmol·g^-1; p = 0.011), were higher on HFOD vs LFOD, respectively. EHS causes the translocation of whole bacteria into systemic circulation and alterations to the plasma bacterial profile, but the FODMAP content of a 24 h diet beforehand does not alter this outcome.

Keywords: I-FABP; bacteremia; breath hydrogen; endotoxin; gastrointestinal symptoms; inflammatory cytokines; running; short chain fatty acids; thermoregulation.

Grants and funding

The study was internally supported by Monash University, Faculty of Medicine Nursing and Health Sciences, Department of Nutrition Dietetics & Food, Be Active Sleep Exercise (BASE) Facility.