Energy-balance studies reveal associations between gut microbes, caloric load, and nutrient absorption in humans.

TitleEnergy-balance studies reveal associations between gut microbes, caloric load, and nutrient absorption in humans.
Publication TypeJournal Article
Year of Publication2011
AuthorsJumpertz, R, Le, DSon, Turnbaugh, PJ, Trinidad, C, Bogardus, C, Gordon, JI, Krakoff, J
JournalAm J Clin Nutr
Volume94
Issue1
Pagination58-65
Date Published2011 Jul
ISSN1938-3207
KeywordsAdult, Bacteria, Energy Intake, Energy Metabolism, Food, Gastrointestinal Tract, Humans, Intestinal Absorption, Male, Middle Aged
Abstract

BACKGROUND: Studies in mice indicate that the gut microbiome influences both sides of the energy-balance equation by contributing to nutrient absorption and regulating host genes that affect adiposity. However, it remains uncertain as to what extent gut microbiota are an important regulator of nutrient absorption in humans.

OBJECTIVE: With the use of a carefully monitored inpatient study cohort, we tested how gut bacterial community structure is affected by altering the nutrient load in lean and obese individuals and whether their microbiota are correlated with the efficiency of dietary energy harvest.

DESIGN: We investigated dynamic changes of gut microbiota during diets that varied in caloric content (2400 compared with 3400 kcal/d) by pyrosequencing bacterial 16S ribosomal RNA (rRNA) genes present in the feces of 12 lean and 9 obese individuals and by measuring ingested and stool calories with the use of bomb calorimetry.

RESULTS: The alteration of the nutrient load induced rapid changes in the gut microbiota. These changes were directly correlated with stool energy loss in lean individuals such that a 20% increase in Firmicutes and a corresponding decrease in Bacteroidetes were associated with an increased energy harvest of ≈150 kcal. A high degree of overfeeding in lean individuals was accompanied by a greater fractional decrease in stool energy loss.

CONCLUSIONS: These results show that the nutrient load is a key variable that can influence the gut (fecal) bacterial community structure over short time scales. Furthermore, the observed associations between gut microbes and nutrient absorption indicate a possible role of the human gut microbiota in the regulation of the nutrient harvest. This trial was registered at clinicaltrials.gov as NCT00414063.

DOI10.3945/ajcn.110.010132
Alternate JournalAm. J. Clin. Nutr.
PubMed ID21543530
PubMed Central IDPMC3127503
Grant ListDK78669 / DK / NIDDK NIH HHS / United States
GM068763 / GM / NIGMS NIH HHS / United States
/ / Intramural NIH HHS / United States