Is there a link between ulcerative colitis and MS?

Ian Cook investigates if there’s a connection between a disease of the bowel and MS

Ever since my diagnosis, more than 30 years ago, I have met people with MS who also have ulcerative colitis (UC). This condition, like MS, is an auto-immune disease but one which affects the colon or large intestine. Here inflammation of the colon leads to ulceration, bleeding and sometimes worse outcomes. It must be hell to have both MS and UC.

Fortunately, I don’t have both, but I come from a family where both conditions are present. My mother had ulcerative colitis all her adult life. Diagnosed in her 30s, my mother’s life and that of her family was difficult. There were huge restrictions on what we could do, where we could go and what we could eat. Even as a child I realised UC was tough.

When I was diagnosed with MS, also in my 30s, I quickly became aware of the striking similarities between the two conditions. Both are typically diagnosed in young adulthood, both commonly have a relapsing-remitting nature, and ‘flare-ups’ in both are treated with steroids. At least one drug, ozanimod, is now used to treat both UC and MS.

Over the years following diagnosis I did some serious reading and discovered other similarities between UC and MS. Both conditions are most prevalent in Northern Europe, North America and newly industrialized nations suggesting a link to Western lifestyle and environment. Worldwide UC has 1.2 cases per 1,000 people, a figure fairly similar to that often quoted for MS.

Recently an academic paper was published titled: ‘Multiple sclerosis and ulcerative colitis: A systematic review and meta-analysis.” The paper reveals that UC can increase your risk of MS by more than 50 pr cent. The risk of developing UC if you have MS is also greater but less so.

Of course, correlation does not mean causation but clearly there is a connection here and for both personal and professional reasons I have been eager to explore it. I am not alone in this task and for years scientists have studied this link between MS and UC as well as a connection between MS and Crohn’s disease (CD) where gastro-intestinal inflammation exists further up the gut. Researchers are just beginning to understand what may be responsible for the association between MS and gastro-intestinal conditions.

Autoimmunity

MS, UC and CD are all autoimmune diseases, meaning the body’s immune system attacks its tissues. It is thought that “leaky gut” may be a contributing factor to MS and UC and possibly CD as well. The term ‘leaky gut’ means the lining of the intestine becomes more porous, allowing toxins and bacteria to leak from the gut into the bloodstream triggering an autoimmune response. In UC, changes to the lining of the gut lead to inflammation and cause gastrointestinal symptoms. The process in MS is believed to be slightly more complex but is believed to start with similar changes in the gut and its lining or ‘epithelium’.

As well as the ‘leaky gut’ there is also the question of whether a specific gut bacterium or bacteria are responsible for ‘gut leakage’. Several studies show MS patients have different gut bacteria or ‘gut microbiome’ compared to healthy individuals, with certain bacteria like Eisenbergia tayi and Lachnoclostridium being more commonly found. Interestingly, both the above bacteria are also thought to play a role in the development of UC too.

Viral link

There is also the question of whether a virus has a role to play. The link between Epstein Barr virus (EBV) and MS is well documented but a recent paper suggested that the virus may be a factor in UC too. The paper published in November 2025 in the European Journal of Gastroenterology was titled ‘Epstein-Barr virus infection increases the risk for inflammatory bowel disease’ and said: ‘Six diagnoses, infectious mononucleosis (glandular fever) , Hodgkin lymphoma, multiple sclerosis, SLE (lupus) , Crohn’s disease, and ulcerative colitis tended to cluster in the same patient population,”. My family is proof of this sad fact.

If further proof of a link were needed, then perhaps the most compelling evidence of a link between UC and MS is based on real-world experience. In 2001 the U.S. Food and Drug Administration (FDA) received more than 20 reports of people with bowel diseases including UC developing MS or MS-like symptoms after using anti-tumour necrosis factor (TNF) medications (a category of experimental drugs being tested in the treatment of bowel diseases). Other clinical trials had also reported their participants experiencing MS symptoms during anti-TNF treatment. The drug trials were hastily halted.

Gut health

Over the past few years, I have become increasingly aware of the role of the gastro-intestinal tract in MS. At diagnosis I read about various MS diets in particular the Swank diet which I followed on and off for years. My mother, after her UC diagnosis radically changed her diet too and that affected us, her family. All processed foods were banned, whole grain foods like wholemeal bread became standard fare, the only sugar allowed was honey, a juicer was bought and yoghurt was made on more or less a daily basis.

Interestingly my mother’s UC improved as her diet changed, so much so that she returned to the workplace when I was a teenager, got a teaching job and then ran a sub-post office with my father until she retired in her mid-sixties. She died aged 93, not a bad outcome given that she had UC for more than 60 years and after diagnosis told me she had been given just a decade or so to live. My mother’s experience has given me much food for thought.

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