Effect, Tolerability, and Safety of Exclusive Palatable Elemental Diet in Patients with Intestinal Microbial Overgrowth

Ali Rezaie; Bianca W Chang; Juliana de Freitas Germano; Gabriela Leite; Ruchi Mathur; Krystyna Houser; Ava Hosseini; Daniel Brimberry; Mohamad Rashid; Sepideh Mehravar; Maria Jesus Villanueva-Millan; Maritza Sanchez; Stacy Weitsman; Cristina M Fajardo; Ignacio G Rivera; Lijin Joo; Yin Chan; Gillian M Barlow; Mark Pimentel

doi:10.1016/j.cgh.2025.03.002

Effect, Tolerability, and Safety of Exclusive Palatable Elemental Diet in Patients with Intestinal Microbial Overgrowth

Clin Gastroenterol Hepatol. 2025 Apr 4:S1542-3565(25)00241-1. doi: 10.1016/j.cgh.2025.03.002. Online ahead of print.

Authors

Ali Rezaie¹, Bianca W Chang², Juliana de Freitas Germano³, Gabriela Leite³, Ruchi Mathur⁴, Krystyna Houser⁵, Ava Hosseini³, Daniel Brimberry³, Mohamad Rashid³, Sepideh Mehravar³, Maria Jesus Villanueva-Millan³, Maritza Sanchez³, Stacy Weitsman³, Cristina M Fajardo³, Ignacio G Rivera³, Lijin Joo³, Yin Chan², Gillian M Barlow³, Mark Pimentel⁶

Affiliations

¹ Medically Associated Science and Technology (MAST) Program, Cedars-Sinai, Los Angeles, California; Karsh Division of Gastroenterology and Hepatology, Department of Medicine, Cedars-Sinai, Los Angeles, California. Electronic address: Ali.Rezaie@cshs.org.
² Karsh Division of Gastroenterology and Hepatology, Department of Medicine, Cedars-Sinai, Los Angeles, California.
³ Medically Associated Science and Technology (MAST) Program, Cedars-Sinai, Los Angeles, California.
⁴ Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Cedars-Sinai, Los Angeles, California.
⁵ mBiota Elemental, Santa Monica, California.
⁶ Medically Associated Science and Technology (MAST) Program, Cedars-Sinai, Los Angeles, California; Karsh Division of Gastroenterology and Hepatology, Department of Medicine, Cedars-Sinai, Los Angeles, California.

PMID: 40189034
DOI: 10.1016/j.cgh.2025.03.002

Abstract

Background & aims: Elemental diets (EDs) have desirable safety and efficacy profiles in several clinical settings partly because of modulation of gut microbiome. Palatability of EDs remains the main barrier to compliance/adherence, and their effect has not been prospectively explored in microbiome-driven disorders, such as small intestinal bacterial overgrowth (SIBO) and intestinal methanogen overgrowth (IMO). We aimed to assess the effect, tolerance, and safety of a novel palatable ED (PED) in subjects with IMO and/or SIBO.

Methods: Adult subjects with positive lactulose breath tests for SIBO and/or IMO completed 1 week of screening, 2 weeks of exclusive oral PED, and 2 weeks of follow-up during reintroduction of regular diet. Primary end point was changes in stool microbiome after PED and reintroduction of regular diet. Secondary end points included tolerability, rate of normalization of lactulose breath tests, change in stool form based on daily diary and artificial intelligence-analyzed images, symptomatic response, and adverse events.

Results: All 30 enrolled subjects tolerated the PED and completed the trial. Several taxonomic differences were detected including decreased relative abundance of Prevotella_9 and Fusobacterium. Abundance of Methanobrevibacter smithii decreased at the end of the trial and correlated with average daily methane levels (P = .024; r = 0.489). Maximum methane levels (41 ± 35 to 12 ± 15 ppm; P < .001) and hydrogen rise (43 ± 42 to 12 ± 11 ppm; P < .001) dropped significantly, with 73% normalizing their lactulose breath tests. Adequate global relief of symptoms was reported in 83% of subjects. No serious or severe adverse events were observed.

Conclusions: PED significantly impacts the gut microbiome. Tolerance to EDs improves with enhanced palatability. Larger studies with longer follow-up are needed to assess response durability. (ClinicalTrials.gov ID: NCT05978973).

Keywords: Archaea; Elemental Diet; Microbiome.

Associated data

ClinicalTrials.gov/NCT05978973