B. adolescentis
The Missing Microbe
Bifidobacterium adolescentis is a prominent member of the human gut microbiota, particularly during adolescence and adulthood, and has been increasingly studied for its beneficial health effects. The available scientific literature suggests that higher levels of B. adolescentis are often associated with healthier aging.
Studies comparing the gut microbiota of healthy older adults and centenarians to those of less healthy or institutionalized elderly individuals frequently show higher relative abundances of B. adolescentis (and other Bifidobacterium species) in the healthier groups. This trend seems to align with broader patterns in gut microbiome composition, where greater diversity and enrichment of beneficial, SCFA-producing microbes are hallmarks of a more resilient and health-promoting microbiota.
While many Bifidobacterium species exist in the human microbiome, only a select few carry out the majority of critical functions that support our health, vitality, and resilience. Our laboratory has analyzed research on microbiome samples of nearly 6000 individuals across 23 countries, and 10 foundational Bifidobacterium species are consistently present from infancy until death. Conversely, microbiome data from unhealthy people shows a deficiency of these keystone species.
Abundance of the top 10 Bifidobacterium
species in healthy individuals by age
Abundance of the top 10 Bifidobacterium
species in unhealthy individuals by age
Abundance of the ten most common Bifidobacterium species in a curated database of shotgun metage sequences from stool samples of 5,966 people across 23 countries. (Pasoli et al., 2017)
Abundance of the ten most common Bifidobacterium species in a curated database of shotgun metage sequences from stool samples of 5,966 people across 23 countries. (Pasoli et al., 2017)
Abundance of total Bifidobacterium
species in healthy vs unhealthy people
Recent evidence suggests that B. adolescentis may influence host metabolic and neurological health. For instance, its presence has been associated with improved glucose metabolism and lipid profiles, potentially contributing to reduced risk of metabolic disorders. Recent research indicates that B. adolescentis may contribute to gamma-aminobutyric acid, GABA, the brain’s primary inhibitory neurotransmitter. Increased GABA production in the gut plays a major role in regulating mood, stress, and anxiety. This interaction is part of the Gut-Brain Axis, a complex communication network linking the gastrointestinal tract and the central nervous system through neural, immune, and metabolic pathways.
In several cohort studies involving centenarians and nonagenarians in regions known for longevity, such as Italy and Japan, B. adolescentis has been found at detectable or even elevated levels, compared to age-matched peers with more frailty, chronic illness, or institutionalized care. Conversely, a decline in Bifidobacterium, including B. adolescentis, has been linked to age-related dysbiosis, which is associated with chronic inflammation (“inflammaging”), metabolic dysfunction, and greater vulnerability to infection.
It’s worth noting that B. adolescentis is typically more dominant earlier in adulthood, and while its levels often decline with age, the preservation of even modest levels into older age appears beneficial and may indicate a healthier gut environment. Maintaining a diet rich in prebiotics (like dietary fiber) and avoiding excessive antibiotic use are factors that likely help preserve such microbes into old age.
While more clinical trials are needed to fully establish causality and therapeutic applications, the existing body of evidence supports B. adolescentis as a promising probiotic species with multifaceted benefits for gastrointestinal, metabolic, and neurological health.
In summary, healthy older adults — particularly those aging successfully with fewer chronic diseases — tend to have higher or more stable levels of B. adolescentis compared to less healthy counterparts, and this is believed to be one of several microbial indicators of healthier aging.
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Chen, J., Wang Q, Wang A, Lin Z. Structural and Functional Characterization of the Gut Microbiota
in Elderly Women With Migraine. Front Cell Infect Microbiol. 2020 Jan 29;9:470.
Chen, S., Chen, L., Qi, Y. et al. Bifidobacterium adolescentis regulates catalase activity and host metabolism and improves healthspan and lifespan in multiple species. Nat Aging 1, 991–1001 (2021).
Davis LM, Martínez I, Walter J, Goin C, Hutkins RW. Barcoded pyrosequencing reveals that consumption of galactooligosaccharides results in a highly specific bifidogenic response in humans. PLoS One. 2011;6(9):e25200.
Davis LM, Martínez I, Walter J, Hutkins R. A dose dependent impact of prebiotic galactooligosaccharides on the intestinal microbiota of healthy adults. Int J Food Microbiol. 2010 Dec 15;144(2):285-92.
Genomic diversity and probiotic traits of Bifidobacterium adolescentis.
Phylogenetic tree showing the relationship of 148 B. adolescentis genomes. From inside to outside, the rings are colored by 1) geographic region where the strains were isolated, 2) genome size, 3) antibiotic resistance genes, 4) GABA genes, 5) genes for antimicrobial compound production, 6) genes for folate biosynthesis 7) β-galactosidase gene copy number, and 8) carbohydrate utilization cluster. Stars indicate which strains were used for in vitro laboratory analyses and animal silhouettes denote non-human isolates.