Extremely healthy seniors appear to have the same bacterial composition in their guts as healthy 30-year-olds, shows new research.
The new study was carried out by researchers at the Lawson Health Research Institute of Western University in Ontario, Canada, in collaboration with those at the Tianyi Health Science Institute in Zhenjiang, China.
The scientists analyzed the gut microbiota of more than 1,000 very healthy individuals aged between 3 and 100 years, and the findings were published in the journal mSphere.
Greg Gloor, a professor at Western University's Schulich School of Medicine & Dentistry, is the senior investigator of the study. The first author of the paper is Gaorui Bian, of the Tianyi Health Science Institute.
Gut bacteria in the young and the elderly
Bian and colleagues used 16S Ribosomal RNA sequencing to analyze the microbial composition of the participants' guts.
The participants were selected based on criteria of "extreme health." These included no reported disease, either in themselves or in their family.
Participants did not smoke, did not consume any alcohol, had no reported moodiness, and had not been prescribed any drugs or antibiotics in the 3 months leading up to the study.
They also had no family history of major cardiometabolic, gastrointestinal, or neurological diseases.
The study yielded several main findings. Firstly, the microbial composition of the extremely healthy seniors resembled that of those who were also healthy but decades younger.
Secondly, the researchers found major differences in the gut microbiota composition only before the age of 20. Between the ages of 30 and 100, the microbiota was largely the same.
Finally, men's composition of the gut microbiota seemed to be "more variable" than women's.
"Taken together," the authors write, "the present findings suggest that the microbiota of the healthy aged in this cross-sectional study differ little from that of the healthy young in the same population."
'Resetting microbiota might promote health'
"The aim is to bring novel microbiome diagnostic systems to populations, then use food and probiotics to try and improve biomarkers of health," says study co-author Gregor Reid, a professor at Western University's Schulich School of Medicine & Dentistry and a scientist at Lawson Health Research Institute.
However, the study cannot explain causality. As Prof. Reid explains, "It begs the question ??" if you can stay active and eat well, will you age better, or is healthy aging predicated by the bacteria in your gut?"
Either way, there remains a strong and undeniable correlation between a healthy gut and healthy aging.
"The main conclusion is that if you are ridiculously healthy and 90 years old, your gut microbiota is not that different from a healthy 30-year-old in the same population."
Prof. Greg Gloor
"Whether this is cause or effect is unknown," write the authors. However, Prof. Gloor explains, "This demonstrates that maintaining [the] diversity of your gut as you age is a biomarker of healthy aging, just like low-cholesterol is a biomarker of a healthy circulatory system."
"By studying healthy people, we hope to know what we are striving for when people get sick," notes Prof. Reid.
The results of the study, the authors write, "[suggest] that resetting an elderly microbiota to that of a 30-year-old might help promote health."