Gut bacteria and the immune system: How aging changes the microbiome and can lead to ‘inflammaging’

• Research has shown that changes to the composition and diversity of the microorganisms in the gut may explain these differences in immune system aging.
• However, as the composition of our gut microbiome changes with age, a low level of inflammation can become constant throughout the body.
• Let’s take a closer look at the gut microbiome and how it changes with age.

Gut microbiome imbalances in older adults

• In fact, compared to other parts of the body, the gut microbiome has the largest number of bacteria.
• In a healthy gut microbiome, there are four dominant families (or phyla) of microorganisms, including Firmicutes, Bacteroidetes, Proteobacteria and Actinobacteria.
• Firmicutes and Bacteroidetes make up around 80 to 90 per cent of the gut microbiota in the digestive tract.
• Over time, the shortage of beneficial bacteria such as Firmicutes in older adults starts to compromise the integrity of their intestinal barrier, causing it to become leaky.

How inflammaging works

• Inflammaging creates an environment that is prone to inflammation, which is caused and maintained by several factors.
• These can include microorganism imbalances in the intestines (microbial dysbiosis), psychological stress, physical inactivity, poor nutrition and chronic infections.

Maintaining a healthy balance of gut microbiota

• More specifically, probiotics help improve the function of the intestinal barrier and regulate immune responses by modifying the composition of the gut microbiome.
• It is clear that the immune system has an intricate relationship with the gut microbiome.
• A healthy and well-balanced gut microbiome will strengthen the intestinal barrier, which helps to reduce inflammation throughout the body and support the immune system.
• To achieve this, it is important to maintain a healthy and well-balanced lifestyle as we grow older.

Narveen Jandu does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.