What are the aging-associated alterations in the diversity, composition, and functional features of the gut microbiota?

In one paragraph

Gut Microbiome Testing (Nutrients 2020, PMID 33297486) — oldest-old adults had functional differences, including greater potential for short-chain fatty acid production and increased butyrate derivatives, compared to young-old adults. No numeric effect size is reported for Gut Microbiome Testing in the source abstract.

Source: Nutrients 2020, PMID 33297486 ↗ · Research map · How Magellan grades evidence · evidence confidence: low

Nutrients · 2020 · PMID 33297486 · DOI 10.3390/nu12123759

Plain-English summary written and published by Magellan Longevity · medical review by Gabriel Radu, DO (physiatrist, NPI 1376861765). We summarize what the paper reported — we did not run this study.

The takeaway

The gut microbiome changes significantly with age, showing higher diversity and specific functional shifts in older adults, especially the oldest-old.

The question

What are the aging-associated alterations in the diversity, composition, and functional features of the gut microbiota?

What they tested

The gut microbiome undergoes extensive changes across the lifespan, and age-related processes may influence the gut microbiota and its related metabolic alterations.

How they did it

This systematic review identified 27 empirical human studies focusing on normal and successful aging to summarize current literature on age-related changes in gut microbiota diversity, composition, and functional features.

What they found

Alpha diversity of microbial taxa, functional pathways, and metabolites was higher in older adults, especially the oldest-old, compared to younger individuals. Beta diversity distances significantly differed across developmental stages and between oldest-old and younger-old adults. Older adults showed reduced pathways for carbohydrate metabolism and amino acid synthesis. Oldest-old adults had functional differences, including greater potential for short-chain fatty acid production and increased butyrate derivatives, compared to young-old adults.

What it means

Older adults, particularly the oldest-old, exhibit distinct gut microbiota characteristics, including higher alpha diversity and specific functional differences like increased short-chain fatty acid production, which may offer insights into age-related processes.

Limitations

A definitive interpretation of the findings is limited by the cross-sectional design of the published reports included in the review.

“the gut microbiome lies at the core of many age-associated changes including immune dysregulation”— from the published abstract, Nutrients 2020

The paper at a glance

Title	The Gut Microbiome, Aging, and Longevity: A Systematic Review
Journal	Nutrients
Year	2020
PMID	33297486 ↗
DOI	10.3390/nu12123759 ↗
Topic	Gut microbiome & digestion

Read the source: PubMed record (authors, abstract, full citation) ↗ · Publisher via doi.org ↗

Where Magellan uses this paper

This citation sits behind the evidence grade on the pages below. Grades are set from the research and are independent of affiliate commissions.

Gut Microbiome Testing

The composition and diversity of the gut microbiota shift with age and influence immunity, metabolism and systemic inflammation. The aging gut microbiome is increasingly viewed both as a marker of biological age and as a modifiable target for anti-aging interventions through diet and probiotics.

Molecules & mechanisms in this paper

Each of these is named in the paper’s own words above. Open the monograph for the full mechanism and its other citations.

Microbiome Butyrate

Cite this page

These citations point at this summary. To cite the original paper with its full author list, use the PubMed record or doi.org.

APA

Magellan Longevity. (2026). What are the aging-associated alterations in the diversity, composition, and functional features of the gut microbiota? [Plain-English summary of Nutrients 2020, PMID 33297486, DOI 10.3390/nu12123759]. Magellan Longevity. https://magellanlongevity.com/study/x11.html

BibTeX

@misc{magellan_x11,
  title        = {What are the aging-associated alterations in the diversity, composition, and functional features of the gut microbiota?},
  author       = {{Magellan Longevity}},
  year         = {2026},
  howpublished = {\url{https://magellanlongevity.com/study/x11.html}},
  note         = {Plain-English summary of PubMed PMID 33297486; DOI 10.3390/nu12123759; Nutrients 2020. Reviewed by Gabriel Radu, DO},
  urldate      = {2026-08-11}
}

Permalink

https://magellanlongevity.com/study/x11.html

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All 4 Magellan summaries on gut microbiome & digestion →

How this summary was made. Every section above restates what the published abstract of PMID 33297486 reports — the question, the design, the numbers, the authors’ own conclusion and their stated limitations. We do not add claims the paper did not make, and we keep negative and no-effect findings in. Magellan’s evidence grades are set from research like this and never from affiliate commissions.

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Educational information, not medical advice. This is a plain-English summary of published research; it is not a treatment recommendation and nothing here is intended to diagnose, treat, cure, or prevent any disease. Individual studies can be wrong, and a single paper rarely settles a question. Talk to your physician before acting on any research, especially if you are pregnant, nursing, or taking medication.