Can your gut microbiome influence inflammation in your body?

Your gut microbiome has a direct connection to your immune system, and a disrupted microbiome can fuel low-grade inflammation throughout the body. When the composition of your gut bacteria becomes unbalanced and the gut wall becomes too permeable, bacterial waste products can enter your bloodstream. Your immune system recognises those substances as intruders and responds with a persistent, smouldering inflammation.

That smouldering inflammation is linked in multiple reviews to a broad range of chronic conditions: obesity, non-alcoholic fatty liver disease, cardiovascular disease, autoimmune diseases and brain disorders. Caution is warranted, however: in most cases it remains unclear whether the disrupted gut microbiome is the cause or rather a consequence of those diseases. The association is consistent, but true cause-and-effect relationships have not yet been conclusively proven in humans for most of these conditions.

What you eat plays a major role. A high-fat, western diet damages the gut wall and disrupts the bacterial composition, after which that low-grade inflammation sets in. Conversely, one randomised study in people with type 2 diabetes showed that increasing dietary fibre improved the gut microbiome and lowered inflammatory markers in the blood. That is promising, but it was one study in one specific patient group.

In older adults, epidemiological research indicates that regular physical activity combined with a Mediterranean diet supports the diversity of the gut microbiome and thereby helps to maintain immune defences. These are associations for now, not proven causal effects. In people with chronic kidney disease there is a similar pattern: bacterial toxins leaking through a disrupted gut wall can worsen inflammation and kidney damage, but here too clinical trials that directly prove this are lacking.

In practical terms: most of the evidence points to fibre, polyphenols (from vegetables, fruit and olive oil) and regular physical activity as the practically achievable levers for favourably influencing your gut microbiome and, with it, your level of inflammation. That is no guarantee, but it is the area with the best substantiation so far.