Earlier this year, ME Research UK funded a new research study led by Prof. Yan Yiannakou in Newcastle looking at changes to the immune system and gut microbiome in patients with ME/CFS and those with irritable bowel syndrome.

Gastrointestinal symptoms are very common among ME/CFS patients, and can include abdominal swelling and/or pain, nausea and vomiting, and abnormal bowel behaviour. Indeed, their presence is one of the criteria that can lead to diagnosis of the illness.

Studies of the dietary habits of individuals with ME/CFS reveal that a significant proportion use nutritional supplements to relieve these symptoms, and many also report food intolerances, including sensitivities to gluten or milk protein. This is borne out by the experiences of many of the people who contact us, and also by the extensive discussions taking place on Internet forums.

So, are dietary supplements or treatments of any benefit to patients with ME/CFS? And which ones are the most helpful?

Even just a brief Google search shows that people have tried a wide range of things in their search for relief, with varying results. But last year a team in Queensland, Australia addressed the question by performing a systematic review of scientific studies in which ME/CFS patients modified or supplemented their diet.

Seventeen studies qualified for the review, and together they investigated a total of 14 different interventions including antioxidants, vitamins and NADH. Many of these did not show any benefits on patient-reported outcomes such as fatigue, physical activity and quality of life, but one intervention that did demonstrate some potential was the use of probiotics.

It is thought that probiotics may have value in ME/CFS by improving the gut microbiome, which is altered in the disease, and by decreasing inflammation.The gut microbiome is the collection of intestinal microorganisms, including bacteria, living on the membranous lining that break down our food and help protect us against infection. There is also evidence that reduced levels of certain gut bacteria may be linked to cognitive problems in ME/CFS.

Which leads us on to a new systematic review recently published in the journal Beneficial Microbes, focusing specifically on the value of probiotic treatments in patients with ME/CFS.

The Spanish team of investigators searched the medical science literature for studies published in the previous decade that looked at the effects of probiotic therapy in patients with ME/CFS. Disappointingly, they only found two, both of which could really be considered pilot studies (i.e. they had a relatively low number of participants). Nevertheless, they were judged to be of high quality with regard to their methodologies and risks of bias. The researchers also looked for studies in fibromyalgia, but found none.

In one study, 48 patients with ME/CFS were treated with the Lactobacillus casei strain Shirota or placebo for 8 weeks. The treatment was well tolerated, and there was a significant decrease in anxiety scores (as measured using the Beck inventory) among those receiving probiotics compared with placebo, but no change in scores of depression. Stool samples taken after treatment showed moderate increases in the quantities of Bifidobacteria and Lactobacillus.

In the second study, 35 ME/CFS patients received either Bifobacterium infantis or placebo, again for 8 weeks, but these investigators focused on changes in markers of inflammation, namely C-reactive protein, interleukin-6 and tumour necrosis factor-α. Following treatment with the probiotic, on average, plasma levels of all three markers were significantly reduced from pretreatment levels, and were also lower than levels in the placebo group (which increased slightly or remained the same). In fact, 71% of patients on probiotics had decreased inflammatory markers after 8 weeks.

So the findings of these two trials indicate that some probiotic strains may be helpful in reducing symptoms of anxiety and inflammation in ME/CFS patients, and they also have an effect on the gut microbiome. That being the case, it seems a shame that there have not been more probiotic trials in ME/CFS (and apparently none in fibromyalgia).

As is so often the case, the investigators have to conclude that more research is necessary to confirm these beneficial effects in more individuals, and using other probiotics. It is also worth mentioning that there were no assessments of other key symptoms of the disease such as pain, fatigue and cognitive dysfunction which may also be influenced by this treatment.

None of us at ME Research UK are medically qualified, so we are not in a position to answer the inevitable question of whether anyone with ME/CFS should try taking probiotics to help manage their own illness. That decision should always be made in consultation with your doctor, although the preliminary findings presented here do indicate they may have a place.

For our part, we are keen to see more research addressing the role of the gut microbiome in ME/CFS, and we look forward to the results that will come from Prof. Yiannakou’s ongoing work.