Lactobacillus (purple) in kefir, which provides microbes associated with gut health STEVE GSCHMEISSNER/SCIENCE PHOTO LIBRARY
ONE of the most compelling discoveries about the gut microbiome is its influence on the immune system. Between 70 and 80 per cent of immune cells are in the gut, where they are constantly communicating with microbes. This crosstalk helps fight disease, strengthen immune responses and regulate inflammation, our body’s first line of defence against infection. Controlling inflammation is critical, as too much damages cells and helps drive chronic illness.
It is no surprise, then, that a growing body of evidence implicates the gut microbiome in various chronic diseases, from arthritis to Alzheimer’s. It is still early days, and most of these findings only point to associations. But they raise the possibility that gut microbes may contribute to, or even cause, some of our most intractable conditions, an idea that has already inspired new treatments.
It is now well established that gut microbiomes in people with conditions like multiple sclerosis, type 1 and type 2 diabetes, Parkinson’s disease and even asthma differ significantly from those of people without an underlying illness. Two papers published earlier this year showed that people with chronic fatigue syndrome – also known as myalgic encephalomyelitis, or ME/CFS – have less of a gut bacterium called Faecalibacterium prausnitzii in their stools. This species produces anti-inflammatory molecules, so a deficit of it could explain the excess inflammation seen in the condition. Low levels of F. prausnitzii are also seen in the guts of people with inflammatory bowel disease (IBD), a group of disorders characterised by chronic inflammation of…
