Researchers at Germany's Max Planck Institute have identified two species of gut bacteria that can help trigger multiple sclerosis.
The breakthrough follows claims made last month by US alternative medicine doctor Jessica Peatross, who posted online that the bacteria triggering the disease had been found. Her post was shared thousands of times and sparked widespread debate, drawing both delight from people hoping for answers and scepticism from critics who questioned the evidence and her credentials.
While experts emphasize that multiple sclerosis is not caused by a single factor, researchers confirmed that growing scientific evidence links stomach bacteria to the incurable condition, suggesting the cascade of events causing the disease may originate in the digestive tract rather than the brain or spinal cord.
Multiple sclerosis affects more than 150,000 people in the UK and around three million worldwide, causing loss of sight, balance issues, crippling fatigue, walking difficulties, and severe paralysis. Between 2000 and 2020, the number of UK patients living with the condition doubled from under 100,000 to 190,000, with patient numbers increasing by roughly six per cent each year.
Doctors have expressed growing concern over a rise in diagnoses among younger people. Around 7,000 new cases are diagnosed in Britain annually, with women approximately two and a half times more likely to be affected than men. The UK records one of the highest rates of the disease globally, although Canada leads worldwide figures with 291 cases per 100,000 people.
Max Planck Twin Study Identifies Bacteria
In a study published in the US journal Proceedings of the National Academy of Sciences, scientists at the Max Planck Institute analyzed sets of twins in which only one sibling had multiple sclerosis. Studying twins raised together allowed researchers to eliminate genetic and environmental differences as potential causes.
By examining bacteria from stool samples and the small intestine, the team identified two specific bacterial species present only in the twins diagnosed with the condition: Eisenbergiella tayi and Lachnoclostridium. When fed to specially bred mice, these micro-organisms made the animals significantly more likely to develop symptoms similar to multiple sclerosis.
The researchers concluded: "We developed a strategy to identify gut bacteria functionally linked to the development of multiple sclerosis. Our results implicate Eisenbergiella tayi and Lachnoclostridium as likely responsible for an increased incidence of disease." The findings sparked thousands of optimistic online responses, with commentators expressing hope for new treatments.
How Gut Microbes Affect the Immune System
Multiple sclerosis develops when the immune system mistakenly attacks body cells, damaging myelin, the fatty protective coating surrounding nerve fibres. Depending on which nerves sustain damage, symptoms vary from extreme tiredness and blurred vision to movement problems and disturbances in memory, thought processes, and emotions.
Ruth Dobson, Professor of Clinical Neurology at the Queen Mary University of London Centre for Preventive Neurology, explained that the immune system is highly active in the gut because many bacteria enter through the digestive tract. She noted that certain structural components of gut bacteria resemble human brain cells.
"MS isn't the result of one single thing; there are lots of factors working together," Professor Dobson said. "But this fascinating study illustrates that bacteria in the gut may be playing some part in triggering the cascade of events that eventually lead to the disease."
She explained that when the immune system reacts against the bacteria, it creates a cross-reactive immune response against brain cells. "Essentially the immune system thinks its attacking the bugs but is actually attacking the myelin on the nerve fibres," she said.
Professor Dobson, who works alongside the MS Society charity, stressed that gut bacteria are part of a broader jigsaw of risk factors. Other known triggers include smoking, lack of vitamin D, adolescent obesity, and infection with the Epstein-Barr virus, a common herpes virus spread through saliva that infects more than 90 per cent of adults globally, often without symptoms.
Dietary Recommendations to Protect Gut Health
While experts state it is too early to offer treatments for specific bacterial species, simple dietary adjustments can improve gut health and potentially reduce risk. Recommendations include replacing ultra-processed foods with a varied diet rich in fibre, fresh fruit, and vegetables.
Professor Dobson advised against buying probiotic drinks and yogurts marketed for gut health, stating there is no evidence they help prevent multiple sclerosis. Instead, she recommended eliminating foods high in refined sugars and chemical additives, such as soft drinks, sugary juices, mass-produced breads, pastries, instant noodles, frozen ready meals, and reconstituted meats like hot dogs and chicken nuggets.
"We increasingly understand that these ultra-processed foods are bad for our brains and our immune system and are linked to immune diseases," Professor Dobson said. "One of the key steps is to have a mixed healthy diet with lots of fresh fruit and veg. We also know that being obese in adolescence doubles the risk of MS in later life. So we need to make sure we're looking after our children's diets as well as our own."
Early Symptoms and Case Study
The importance of early detection is illustrated by the experience of Becky Lee, a 32-year-old project manager from Bristol. She first experienced symptoms at age 21, including dizzy spells, muscle spasms, weakness down her left side, and a sensation that her vision was shaking or vibrating, though eye tests showed no problems.
Lee repeatedly explained away her symptoms, attributing them to indigestion or vitamin deficiencies. In 2015, doctors diagnosed her with clinically isolated syndrome, a condition that can precede multiple sclerosis. Frightened by the potential diagnosis, she declined an MRI scan, but after symptoms worsened, she was diagnosed with relapsing-remitting multiple sclerosis in 2023.
"Looking back, these were early warning signs," Lee said. "I didn't realise they were connected."
Future Outlook for MS Prevention
Understanding the triggers behind multiple sclerosis provides valuable answers for patients while offering hope for early detection and prevention strategies.
"People living with MS want to know why it's happened to them," Professor Dobson said. "The psychology of explanation means it is important for people to understand why they developed the disease. Meanwhile, MS is a condition that we can't currently prevent or cure. Being able to establish why some people get it might allow us to identify them earlier or even prevent them from getting the disease in the first place. Anything that advances us on that journey is a very good thing."
She added: "The dream is that, in the future, we may be able to screen for specific bacteria to identify people who might be at increased risk. It's still a long way off, but there may even be a way of targeting those bacteria to stop people from getting MS."
