ORIGINAL RESEARCH article
Front. Aging
Sec. Healthy Longevity
First Metagenomic Analysis of Age-Associated Changes in the Gut Microbiome Among Healthy Saudi Adults: SAMS Pilot Study
Roua Almatrafi 1,2
Abdulrahman Alasiri 3,4
Ghaida Almuneef 3,4
Amal A Al-Hazzani 1
Majed F. Alghoribi 2,5,4
Maymounah Hakami 2,4
Assad Arafah 6,7,8
Raniah Saleem Alotibi 9,4
Shatha Alrabiah 4,6,10
Nasser Alqurainy 2,4,5
Reham Ajina 4,6,9
Marwh Gassim Aldriwesh 9,2
1. College of Science, Department of Botany and Microbiology, King Saud University, Riyadh, Saudi Arabia
2. Infectious Disease Research Department, King Abdullah International Medical Research Center, Riyadh, Saudi Arabia
3. Department of Artificial Intelligence and Bioinformatics, King Abdullah International Medical Research Center, Riyadh, Saudi Arabia
4. Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
5. College of Science and Health Professions, Department of Basic Science, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
6. King Abdullah International Medical Research Center, Riyadh, Saudi Arabia
7. Department of Family Medicine, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
8. College of Medicine, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
9. College of Applied Medical Sciences, Department of Clinical Laboratory Sciences, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
10. College of Applied Medical Sciences, Department of Clinical Nutrition, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
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Abstract
Abstract Introduction: The gut microbiome undergoes dynamic changes with aging across diverse healthy populations. However, data from Saudi Arabia remain limited. This pilot study investigated age-related variations in the gut microbiome among healthy Saudi adults to characterize region-specific microbial signatures and identify taxa potentially associated with aging in a healthy population. Methods: We established the Saudi Aging and Microbiome Study (SAMS) to investigate age-related changes in fecal microbiome of Saudi adults. In this pilot phase, 145 healthy participants aged 19–69 years were enrolled. Shotgun metagenomic sequencing was performed to profile fecal microbiome at the species level. Microbial diversity and taxonomic composition were compared across five age groups. Spearman and confounder-adjusted partial Spearman correlation were applied to identify taxa significantly associated with chronological age. Results: We analyzed fecal microbiome of 145 healthy adults distributed among five age groups: G1 (19–29 years, n = 33; 22.7%), G2 (30–39 years, n = 30; 20.7%), G3 (40–49 years, n = 27; 18.6%), G4 (50–59 years, n = 31; 21.4%), and G5 (60–69 years, n = 24; 16.6%). Of these, 75 (51.7%) were male, and 70 (48.3%) were female. Alpha diversity increased from young to older adulthood for observed richness and Shannon indexes (all q < 0.05). Beta diversity also varied significantly with age (PERMANOVA R² = 0.13, q = 0.023), indicating distinct microbial community structures in healthy older adults. At the phylum level, Firmicutes significantly increased with age (FC = 1.35; q = 0.026), whereas Bacteroidota decreased (FC = 0.59; q = 0.01). Consistent with these trends, Blautia obeum showed positive correlations, while Bacteroides thetaiotaomicron and Phocaeicola vulgatus showed negative correlations with chronological age. Conclusions: In healthy Saudi adults, increasing age was associated with higher microbial diversity and compositional shifts at phylum and species levels. These age-associated microbial taxa might represent biomarkers of healthy aging and suggest an enhanced community capacity for short-chain fatty acids (SCFAs) production, a hypothesis warranting validation through future functional analyses.
Summary
Keywords
Age-associated change, gut microbiome, Healthy adults, Metagenomics, Saudi Arabia
Received
27 October 2025
Accepted
17 February 2026
Copyright
© 2026 Almatrafi, Alasiri, Almuneef, Al-Hazzani, Alghoribi, Hakami, Arafah, Alotibi, Alrabiah, Alqurainy, Ajina and Aldriwesh. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Marwh Gassim Aldriwesh
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