Two studies shed light on the link between the state of the microbiota and longevity

A microbiota that changes throughout life

The intestinal microbiota refers to all the microorganisms living in our digestive tract.

It evolves from birth and changes over the years under the influence of many factors, including diet, lifestyle and environment.

In adolescents and young adults, it often reaches a high level of microbial diversity. With age, its composition can become less stable, with some species declining while others increase (1).

To study this complex ecosystem and draw out relevant observations, researchers are analysing in particular:

• bacterial diversity
• the stability of microbiota composition over time
• the production of metabolites, such as short-chain fatty acids
• interactions with the immune system

In some studies, a less diverse microbiota has been associated with chronic low-grade inflammation, sometimes called 'inflammaging' (2).

This low-grade inflammation is itself associated with a progressive decline in certain functions (3) that we see as we age, such as:

• muscle function
• energy vitality
• certain cognitive abilities

Diet, physical activity and, more broadly, lifestyle influence the composition and functioning of the intestinal microbiota.

To the extent that we can influence these parameters on a daily basis, we could potentially be acting indirectly on this ecosystem.

Two studies look at the links between microbiota and ageing

Results revealing links between microbiota and maintenance of vitality

A narrative review summarising several studies linking microbiota and ageing

This review (4) summarises several experimental studies suggesting that alterations in the microbiota could be associated with chronic low-grade inflammation, often referred to as 'inflammaging'.

It also discusses the role of the intestinal barrier: an increase in permeability could promote the passage of certain bacterial compounds into the bloodstream, potentially contributing to systemic inflammation.

The intestine-muscle axis is also discussed, with studies suggesting that certain metabolites produced by the microbiota could be associated with variations in muscle mass and function.

The gut-brain axis has been a particular focus of study in recent years, and is also being explored, particularly via interactions between the microbiota, the immune system and neurotransmitters.

Finally, the production of short-chain fatty acids, particularly butyrate, is presented as a key mechanism: by helping to maintain the integrity of the intestinal barrier, these metabolites could contribute to immune modulation.

In conclusion, the review mentions probiotics, prebiotics and postbiotics as potential avenues for nutritional intervention, while reiterating the need for further clinical trials.

An observational study in adults aged over 60

In this study (5), the researchers compared older adults with a group of very elderly individuals (aged 90 and over).

In the oldest group, they described a microbiota enriched in bacterial genera such as Akkermansia and Bifidobacterium: these could therefore be more typical of the microbiota of people who reach a very advanced age.

The study also reports associations between certain bacteria and physical function parameters, in particular grip strength.

Correlations are also explored with factors such as anxiety and certain dietary habits, such as milk consumption, which could influence the composition of the microbiota.

The authors point out, however, that these are primarily observational associations, and that a correlation does not demonstrate a causal link.

Ultimately, the review and the study support the idea that some microbial profiles could be associated with better vitality in the very elderly, without it being demonstrated that they are the direct cause.

Mechanisms that could explain the potential impact of the microbiota on ageing

Several plausible biological mechanisms have been proposed to explain the associations observed between microbiota and ageing.

Short-chain fatty acids, such as butyrate, could be associated with inflammatory balance by serving as a source of energy for colon cells and helping to maintain the integrity of the intestinal barrier.

In fact, a more functional intestinal barrier is likely to limit the passage of certain pro-inflammatory compounds into the bloodstream, which could help modulate the chronic low-grade inflammation observed with age.

Links have also been suggested between microbiota and muscle function. In some experimental models, bacterial metabolites could influence the mechanisms involved in protein synthesis and the maintenance of muscle mass.

Finally, the study of the gut-brain axis highlights complex interactions between the microbiota, the nervous system and the immune system, which could be associated with certain neuro-psychological aspects observed during ageing.

However, these data are mainly based on experimental models or observational studies, and do not demonstrate that a particular microbiota increases lifespan.

Above all, they support the idea that the microbiota constitutes a serious field of research into the health of the ageing population, influenced in particular by diet and lifestyle.

How can we support our microbiota as part of a 'pro-longevity' approach?

The main pillars of a diverse and stable microbiota are based, above all, on a healthy lifestyle:

• eating a varied diet rich in fibre from legumes, fruit, vegetables and wholegrain cereals
• limiting ultra-processed and high-sugar foods
• engaging in regular physical activity
• maintaining good-quality sleep
• managing stress on a daily basis
• reducing or eliminating alcohol and tobacco consumption

Dietary fibre plays a central role, as it serves as a substrate for intestinal bacteria that produce short-chain fatty acids, which have been studied for their interaction with metabolic and inflammatory balance.

Within this overall framework, certain food supplements can form part of a coherent nutritional approach, without taking the place of an adapted lifestyle.

Probiotic-based formulas are studied for their interaction with the intestinal ecosystem and their potential role in balancing it, in certain contexts.

Discover Full Spectrum Probiotic and Probio Forte food supplements, broad-spectrum multi-layer formulas for maximum microbial diversity.

You can also turn to food supplements formulated to support ageing.

Research is focusing in particular on NAD+, a central cofactor in cellular energy metabolism, which is being studied for its role in specific biological pathways associated with ageing.

Some supplements provide precursors that help the body to synthesise NAD+.

Discover the NAD+ Booster Formula food supplement, which provides precursors involved in the body's synthesis of NAD+.

More broadly, research into the biology of ageing describes several mechanisms involved over the years, often grouped together under the term ‘hallmarks of ageing’:

• genomic instability (DNA damage that accumulates with age)
• telomere attrition (shortening of the caps that protect chromosomes, leading to cell ageing)
• epigenetic alterations (changes in the regulation of gene expression contributing to ageing)
• deficient macroautophagy (impaired elimination of damaged cellular components)
• loss of proteostasis (protein misfolding and aggregation leading to cell dysfunction)
• deregulation of nutrient sensitivity (age-related disturbances in metabolic pathways)
• mitochondrial dysfunction (leading to reduced energy production and increased oxidative stress)
• cellular senescence (accumulation of 'zombie cells' releasing inflammatory signals)
• chronic inflammation (which accelerates biological wear and tear)
• depletion of stem cells (which impairs tissue regeneration capacity)
• altered cellular communication (often due to chronic inflammation)
• dysbiosis of the intestinal microbiota (imbalance)

Discover the Daily Longevity food supplement, made from 13 ingredients studied for their influence on these different parameters within the body.