It has already been well-established that inflammation drives aging in all animals, including the mice used in this study. Higher than average inflammation in the blood has been linked to lower life expectancy, poorer general health, reduced quality of life and a higher risk of chronic illness compared to the average person. Therefore, reducing inflammation could lead to living a longer, healthier, happier life. This is why the discovery of a causal connection between changes in intestinal bacteria and age-related inflammation is so important.
|Yoghurt can be a source of probiotics. Source: Schwaebin.|
The inflammatory mediator known as tumour necrosis-factor (TNF), which is produced by the immune system during times of infection, is responsible for much of the damage. Mice that couldn't produce TNF exhibited less age-related inflammation, less changes to intestinal bacteria and less intestinal permeability (known as "leaky gut" in many naturopathic circles). Reducing TNF led to a "younger" composition of bacteria, and transplanting the bacteria of younger mice into older mice also led to improvement in permeability. This could mean that there are two ways to fight this mechanism of inflammaging: reduce TNF, or change the composition of intestinal bacteria.
Let's look at changing the composition of bacteria, with probiotics. Using a model of the human intestinal tract, researchers looked at the effects of bacteria species commonly included in probiotics. Multiple species of Lactobacillus and Bifidobacterium were compared by their ability to reduce TNF-alpha, the interleukins -4 and -1beta, as well as lipopolysaccharides, which are another type of inflammatory mediator. The species that produced the most dramatic reductions in TNF-alpha were L. plantarum, B. animalis, B. longum and B. longum subspecies infantis. These all reduced TNF-alpha by around two-thirds. B. longum and its infantis subspecies, like L. rhamnosus and B. bifidum, also had significant effects against lipopolysaccharides, which are linked to inflammatory illness. So probiotics may help fight inflammaging, but it is best to get a broad-spectrum product that includes the "best" strains from a qualified practitioner in order to ensure quality.