Summary: A large new study finds a clear association between overall health and gut bacteria in older adults. Healthy elderly individuals in this Chinese cohort had gut microbiota profiles much like those of people decades younger.
Source: Western University.
Researchers from Western University, Lawson Health Research Institute and the Tianyi Health Science Institute in Zhenjiang, China, report one of the largest human microbiota studies to date and identify a strong link between healthy aging and a balanced gut microbiome.
Through the China-Canada Institute, the research team analyzed the gut bacterial communities of more than 1,000 self-selected, very healthy Chinese participants ranging in age from 3 to over 100 years. These volunteers reported no known chronic illnesses and no family history of major disease, allowing the investigators to profile the gut microbiome associated with unusually robust health across the lifespan.
The study used high-throughput 16S rRNA gene sequencing combined with a compositional data analysis framework to evaluate microbiome composition, diversity, and effect sizes. The results indicate a tight relationship between health status and the gut microbiome: overall microbial composition in the exceptionally healthy elderly resembled that of healthy adults decades younger.
“Our aim is to develop practical microbiome diagnostics and then explore nutritional and probiotic approaches to improve biomarkers of health,” said Gregor Reid, PhD, professor at Western’s Schulich School of Medicine & Dentistry and scientist at Lawson Health Research Institute. “This raises an important question—does maintaining an active lifestyle and a nutritious diet preserve a youthful gut microbiome, or do specific gut bacteria help determine who ages healthily?”
The principal investigator, Gregory B. Gloor, PhD, also at Western and Lawson, emphasized the central finding: “If you are exceptionally healthy at 90 years old, your gut microbiota can look much like that of a healthy 30-year-old in the same population.” The study cannot determine causation from correlation, but a key result is that diversity of the gut microbiome—a commonly used marker of microbial ecosystem health—remained consistent among healthy adults from age 30 through centenarians.
Gloor compared microbiome diversity to standard clinical biomarkers: “Maintaining gut diversity as you age appears to be a biomarker of healthy aging, similar to how low cholesterol is a marker of a healthy cardiovascular system.” The authors suggest the possibility that deliberately restoring an elderly person’s microbiome toward the profile of a healthy younger adult might support better health outcomes, though intervention trials are required to test that idea.
Studying very healthy people creates a baseline for what a healthy human gut microbiome looks like, according to Reid: “By understanding the microbiome of healthy individuals, we gain a target for comparison when people become ill.”
The researchers also observed an unexpected and distinct gut microbiota pattern in participants aged 19 to 24. This unique profile was not seen in many other large-scale studies and may reflect specific lifestyle, dietary, or developmental differences in this particular healthy cohort. The finding was consistent across the dataset but requires further investigation to determine its cause and whether it appears in other populations.
Source: Crystal Mackay – Western University
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Original Research: Full open access research: “The Gut Microbiota of Healthy Aged Chinese Is Similar to That of the Healthy Young” by Gaorui Bian, Gregory B. Gloor, Aihua Gong, Changsheng Jia, Wei Zhang, Jun Hu, Hong Zhang, Yumei Zhang, Zhenqing Zhou, Jiangao Zhang, Jeremy P. Burton, Gregor Reid, Yongliang Xiao, Qiang Zeng, Kaiping Yang, and Jiangang Li. Published in mSphere, October 2017. DOI: 10.1128/mSphere.00327-17.
Abstract
The Gut Microbiota of Healthy Aged Chinese Is Similar to That of the Healthy Young
Reports on the microbiota of older adults vary: some studies find reduced diversity in the aged, others find similar or even increased diversity compared to younger cohorts. Methods and cohort definitions differ between studies, and traditional null-hypothesis statistical tests can be difficult to reproduce with large multivariate microbiome data. In this cross-sectional analysis of more than 1,000 very healthy Chinese individuals aged 3 to over 100, we applied compositional data analysis and effect-size measures to examine ordination, differential abundance, and correlation in a reproducible framework. Our key findings: (1) the overall microbiota composition of the healthy aged resembled that of people decades younger in the same population; (2) the most pronounced microbiota differences occurred before age 20; (3) the gut microbiota varied little among individuals from ages 30 to over 100; and (4) male gut microbiota showed greater variability than female. These results suggest that, within this healthy cohort, the microbiota of elderly participants differs little from that of healthy young adults, though minor variations depend on the comparison group.
Importance This study demonstrates large-scale application of compositional data analysis to define a baseline gut microbiota composition in an exceptionally healthy population. That baseline can be used to compare future cohorts with chronic or acute disease. Aside from expected differences between children and adults, we found the elderly microbiota in this population to be similar to that of much younger healthy individuals, a pattern that may reflect active lifestyles and diet but cannot be interpreted as causal in this cross-sectional design. A noteworthy and reproducible exception is a distinct gut microbiota in people in their 20s, which merits further study.