Same MS gut bacteria pattern found in people across the US and Asia

A new analysis of previously published research has found that people living with multiple sclerosis (MS) exhibit subtle yet consistent changes in their gut bacteria, and these variations were consistent across the populations of the US and Asia.

The gut is home to billions of bacteria and other tiny organisms, collectively known as the gut microbiome. While these microorganisms can significantly influence human health, our understanding of their effects is still in its early stages.

In recent years, numerous studies have explored whether there are differences in the gut microbiome between people with MS and those without the condition. While many of these studies have reported notable differences, the findings have often varied from one study to another.

Studying the gut microbiome is particularly challenging because the composition of gut bacteria can be influenced by factors such as environment and diet, which can vary widely between individuals from different regions or cultural backgrounds.

To gain a clearer understanding of MS-related changes in the gut microbiome, researchers conducted a meta-analysis. This approach involves combining data from multiple studies and analysing it as a whole. The meta-analysis included data from seven previous studies – five from the US, one from China, and one from Japan—covering a total of 257 people with MS and 267 without. Most of the MS patients (98.4%) had the relapsing-remitting form of the disease.

The results showed that people with MS consistently had lower-than-normal levels of bacteria from the Faecalibacterium group, which is thought to have anti-inflammatory properties. Low levels of these bacteria may contribute to the inflammation seen in MS. Additionally, MS patients had higher-than-normal levels of bacteria from the Actinomyces group, which is commonly found in the human digestive tract, especially in the mouth.

Another type of bacteria, Prevotella, was also found at lower levels in MS patients compared to those without MS. In a healthy microbiome, there is typically an inverse relationship between Prevotella and another group called Bacteroides, meaning that higher levels of one are usually associated with lower levels of the other. However, this normal relationship was not observed in people with MS.

Overall, the findings suggest that “there are consistent microbial signatures associated with MS across studies,” according to the researchers. However, they cautioned that their analysis looked at broad groups of bacteria rather than individual species, so more research is needed to understand the specific role of these bacteria in MS.

The researchers also noted that the biggest source of variation between studies was not the disease itself but the different methods used to analyse gut bacteria. They emphasised the importance of developing standardised procedures for future research on the gut microbiome in MS.