A team of University of Tokyo scientists summarised various studies which showed probiotics helped increase the number of beneficial bacteria in the microbiome, particularly Bifidobacterium spp., Akkermansia munichipilla and Faecalis praunitzii.
At the same time, they searched for evidence proving prebiotics supplied key substrates for healthy colonic microbial fermentation – a key process to maintaining daily bodily functions and, by association, reducing inflammation.
“Ageing is typically accompanied by biological and physiological changes that alter cellular functions. Two of the most predominant phenomena in aging include chronic low-grade inflammation (inflammaging) and changes in the gut microbiota composition (dysbiosis).
“Although a direct causal relationship has not been established, many studies have reported significant reductions in inflammation during aging through well-maintained gut health and microbial balance,” said the researchers.
Their review titled The Potential Roles of Probiotics, Resistant Starch, and Resistant Proteins in Ameliorating Inflammation during Aging (Inflammaging) was published in the journal Nutrients.
They performed a search through PubMed and Google Scholar databases until December 2021.
One of the key challenges they identified was to maintain the level of beneficial bacteria as people age.
This is because as they decline, they are replaced with the bacteria that instead promote chronic inflammation, the researchers wrote.
“The likely decrease or even disappearance of bifidobacteria with age has been well documented. A study by Bragi et al. supported this by confirming the populations of bifidobacteria, some members of Firmicutes, including Clostridium clusters IV (Ruminococcus obeum et rel., Roseburia intestinalis et rel., Eubacterium ventriosum et rel., E. rectale et rel., and E. hallii et rel.), and some members of Clostridium cluster XIVa, including Papillibacter cinnamovorans et rel. and F. prausnitzii et rel., decreased in aged individuals and centenarians,” added the researchers.
Whether gut dysbiosis during ageing is the cause or consequence of inflammaging remains unclear.
However, the researchers pinpointed some opportunities to maintain good gut health, namely via short-chain fatty acid (SCFA)-producing probiotics, or probiotics with potential anti-inflammatory activities, resistant starch, and resistant proteins.
SCFA has long been understood to be a beneficial metabolite produced by gut bacteria via colonic fermentation of indigestible fibres.
In terms of probiotics, they said research indicated that Lactobacillus spp, bifidobacteria, and Akkermansia muciniphil helped produce the inflammation-reducing SCFA butyrate.
For prebiotics, they noted that the correlation between consumption and gut health, inflammatory markers, insulin response, and lipid metabolism has been well-documented. However, studies with elderly subjects are limited.
Finally, they indicated that more research would be beneficial to assess the relevance of resistant proteins in relation to SCFA production.
These are usually found in plant-based foods, but the researchers found that studies are limited to buckwheat protein, sericin and the recently revealed eggshell membrane (ESM).
In terms of the latter, they added: "Recently, our research group identified eggshell membrane (ESM) as a resistant protein because of its low digestibility (approximately 46%) based on a study in rats. ESM is a by-product of egg with interesting bioactivities, including anti-inflammatory activity, skin- and joint-health-promoting functions, and wound-healing properties. We showed that ESM, as a resistant protein, could stimulate cecal fermentation and alter intestinal bacterial composition".
They concluded that multiple studies have demonstrated that probiotics possessing anti-inflammatory activities and resistant starch can abate ageing-related chronic low-grade inflammation.
However, they also said there are considerable opportunities to enhance understanding: “All findings elaborated in this review are expected to trigger further exploration of resistant proteins, probiotics, and resistant starch in maintaining gut health, targeting inflammaging, and promoting healthy ageing".
“The Potential Roles of Probiotics, Resistant Starch, and Resistant Proteins in Ameliorating Inflammation during Aging (Inflammaging)”
Authors: Dwina Juliana Warman, et al