Skip to main content
NUTRITION 2023 Main banner
Icon Legend
This session is not in your schedule.
This session is in your schedule. Click again to remove it.
Back

Session: Diet-microbiome Interactions in Health and Disease (Oral 22)

(OR22-02-23) Negative Energy Balance Alters Gastrointestinal Function and Gut Microbiota Composition During Strenuous Physical Activity

Monday, July 24, 2023
4:12 PM – 4:24 PM ET
Location:  Commonwealth
Disclosure(s):
Cassandra Suther, PhD: No relevant financial relationship(s) with ineligible companies to disclose.
Jess A. Gwin, PhD: No relevant financial relationship(s) with ineligible companies to disclose.
J. Philip Karl, PhD, RD: No relevant financial relationship(s) with ineligible companies to disclose.
Objectives: Changes in gastrointestinal (GI) permeability and gut microbiota composition can occur during military training characterized by high physical activity and negative energy balance. The impact of energy balance on those responses is not known. This study aimed to determine the effects of altering energy balance during a period of high physical activity on GI permeability and the gut microbiome.

Methods: Ten healthy men (22 ± 5 yr) participated in a randomized, crossover study that included 12 h of baseline testing (BL) and then two 72 h periods of high physical activity (PA; ~4700 kcal/d energy expenditure) followed by 7 d of recovery. During PA, provided diets were matched on macronutrient proportion and maintained energy balance (BAL; 689 ± 852 kcal/d) or created an energy deficit (DEF; -2047 ± 920 kcal/d). GI transit time and pH (SmartPill), GI permeability (dual saccharide absorption test [DSAT], serum LPS binding protein [LBP]), gut microbiome composition (shotgun sequencing), and fecal short chain fatty acid (SCFA) concentrations were measured during BL, DEF, and BAL.

Results: Colonic transit time was longer during DEF versus BAL (mean difference: 768 min [95% CI: 364, 1173]) and BL (693 min [307, 1080]; p = 0.03). GI permeability measured by DSAT was higher during DEF versus BAL (17% [5, 32]) and BL (15% [2, 30], p = 0.03), while LBP increased 27% ([1, 53], p < 0.001) during PA independent of diet. Species-level microbiome α- and β-diversity did not differ between conditions, and taxa relative abundances did not differ from BL during DEF or BAL. However, the relative abundance of several potentially beneficial genera including Bifidobacterium, Blautia, Enterococcus and Faecalibacterium, and species within those genera including B. adolescentis, B. longum, B. wexlerae, E. faecalis, and F. prausnitzii were lower during DEF versus BAL (p ≤ 0.05, q ≤ 0.25). Gene pathway relative abundance, colon pH and fecal SCFA concentrations did not differ between conditions. No differences were observed between BAL and BL for any outcome.

Conclusions: Failure to increase intake to maintain energy balance during short-term periods of high physical activity may adversely impact GI function and gut microbiota composition.

Funding Sources: MRDC & JPC-5. Views are the authors’ and do not reflect Army, DoD, or Government policy.