Study Links MS and Eating Meat

Eating more meat, having lower levels of a certain gut bacteria, and elevated levels of certain immune cells in the blood all correlate with multiple sclerosis (MS), according to a team of researchers led by UConn Health and Washington University School of Medicine.

MS is an autoimmune disease in which the body attacks the insulation surrounding its nerves. When the insulation is damaged enough, the nerves begin to misfire and malfunction.

It is not known what triggers the body to attack the insulation in the nervous system in the first place. Evidence is mounting, however, that bacteria might be involved in MS. It is already known that bacteria living in our guts can affect our immune system, and what we eat affects the gut bacteriome. And while MS affects less than 3 million people globally, it is more prevalent in specific regions—particularly the northern mid-latitudes, suggesting that geography, and perhaps diet, plays a role in the disease.

Dr. Laura Piccio from Washington University, who is now at the University of Sydney, and Dr. Yanjiao Zhou at UConn Health School of Medicine, set out to analyze the relationship between diet, gut microbiome, the immune system and metabolism and their contribution to disease pathogenesis and progression in people with MS. The study included  49 volunteers—25 MS patients and 24 healthy controls—to look for correlations that might be subtle but important.

“We found a number of gut bacteria associated with MS and severity of disability of MS patients. We also found increased autoimmune markers and signature metabolites in MS. But what is really interesting is how these systems connect with each other, and how diet is involved in these connections. Using multi-OMICS approaches, we try to close the loop and show the associations between multiple systems,” Zhou says.

The strongest systemic linkage the researchers found involved eating meat. Their analysis linked higher meat consumption to a decrease in the population of Bacteroides thetaiotaomicron in people’s gut ecology. B. thetaiotaomicron is associated with digesting carbohydrates from vegetables. Higher meat consumption, which was observed in the MS patients, was also linked to an increase in T-helper 17 cells in the immune system, and an increase in S-adenosyl-L-methionine (SAM) in their blood.

Some healthy volunteers did eat a lot of meat, but the pattern of all the factors was suggestive that, in MS, something goes wrong with people’s gut bacteria that dissociates them from the immune system, leading to heightened T-helper 17 cells and autoimmune attacks on the nervous system. And it tends to be associated with meat eating.

“It opens a new modality to address future scientific questions by not looking at one individual factor, but at their complex interactions. This approach can lead to the identification of relevant networks that could be manipulated for disease prevention or therapeutic intervention,” says Piccio.

Future work includes expanding the research to include more people, including those with a more severe form of MS. Eventually, the team hopes to understand more of the cause-and-effect between diet, bacterial ecosystems in the gut, and immune response, and potentially help prevent or mitigate MS symptoms in people suffering from the disease.

The work was published in a recent issue of EBioMedicine.