More of us—mostly women—will live to celebrate our 100th birthdays. The number of centenarians across the globe is growing rapidly, thanks to medicine and technology.
Let’s all shoot for smooth sailing.
Aging changes are inevitable and built into the DNA of every cell. The immune system weakens in aging, making the elderly more likely to catch colds, flus, and also deadly infections from germs including Clostridium difficile which are rampant in hospitals.
What happens to the microbiome?
The human microbiome is pretty stable across the arc of adulthood, say experts. Not so in young childhood and old age, when microbes ride a roller coaster of dramatic changes. In between, they settle into a nice community: it appears that the mutual benefits please both the host (us) and microbiota over decades until the aging process derails it.
Yes, the microbiota changes. But is it different because of the physiological changes of aging or is the changing microbiome promoting aging? Good question which dogs much of medicine and one which is not answered here. The following researchers sought to better identify the changes.
Simone Rampelli and colleagues in Italy published their results as Functional metagenomic profiling of intestinal microbiome in extreme ageing in a journal called Aging in December of 2013.
The study applied “shotgun sequencing to total fecal bacterial DNA in a selection of samples belonging to a well-characterized human ageing cohort.”
The samples: 3 centenarians, aged 99 to 102 years; 5 elderly people, including 3 offspring of the centenarians, aged 59 to 75 years and one 38-year-old adult, as a young control.
Observed in centenarians:
- increase in Proteobacteria
- a shuffling of Firmicutes
- loss of genes for short chain fatty acid production
- decrease in the saccharolytic (sugar breakdown) potential
- proteolytic (protein breakdown) functions were more abundant than in the intestinal metagenome of younger adults
- enrichment in “pathobionts” which are “i.e. opportunistic pro-inflammatory bacteria generally present in the adult gut ecosystem in low numbers. “
Also, the merely “elderly” people (the 59-75 year olds) showed a gut microbiota similar to the one shown by the young adult.
Thus, microbiome structure and function are quite different at the end of our time on earth. Disease states, exercise and diet all impact the changes.
One recent study with elderly people demonstrated diet as a force in microbiota alterations in respect to different rates of frailty in aging.
The authors also concluded: “The individual microbiota of people in long-stay care was significantly less diverse than that of community dwellers. Loss of community-associated microbiota correlated with increased frailty.”
All this evidence may be a cause to celebrate. Perhaps we do have some sway in this formidable challenge of aging.