Inflammatory bowel disease (IBD) affects over 6.8 million people worldwide, with current treatments often causing side effects and poor patient compliance. Dysbiosis of gut microbiota is a key factor, and while probiotics are considered safe and beneficial, conventional strains fail to function effectively during active inflammation due to high iron levels in the gut. Streptococcus thermophilus (FX856), unlike traditional probiotics, can thrive in this iron-rich environment, promoting mucosal healing. A 2-way crossover intervention study will be conducted with FX856 supplementation in overweight and obese individuals who often exhibit mild gut inflammation by measuring faecal calprotectin and systemic inflammatory markers.

There is a lack of satisfactory treatments for inflammatory bowel disease (IBD), an excruciatingly debilitating condition which affects 1 in 123 people in the UK (>0.5million). Current treatments have significant negative side effects, affecting quality of life of patients and reducing compliance, leading to exacerbation of symptoms. Dysbiosis in the composition of gut microbiota is one of the leading causes of chronic inflammatory diseases such as inflammatory bowel disease (IBD). Supplementation with dietary components is a promising approach for the treatment of inflammatory bowel disease (IBD) and the use of probiotics for IBD treatment has shown promising effects on consumers' quality of life, they are popular due to their perception as safe, natural treatments but currently marketed products cannot function during active disease. Streptococcus thermophilus (FX856) is an OTC supplement already available in the UK that has a unique ability to survive and thrive during active inflammation, allowing it to promote mucosal healing in the inflamed gut, an area where conventional probiotics have failed. During active inflammation or stress, gut iron levels increase. This iron-rich environment compromises the suitability of conventional probiotic bacteria that have been, and are still, commonly trailed for the relief of symptoms in patients suffering from gut inflammation. Whilst most constituents of the gut microbiome are able to increase growth rate in response to iron, species traditionally employed as probiotics, such as lactobacilli and bifidobacteria, are unable to use iron as a growth factor; they are outcompeted under high iron conditions and cannot have a beneficial effect. Unlike most bacterial strains used as probiotics, FX856 can maintain growth within an iron-rich environment, as observed in the inflamed intestine. Faecal calprotectin is considered a suitable non-invasive surrogate marker of intestinal inflammation in inflammatory bowel disease and is reported to be increased in obese individuals. Consequently, this study will determine how the probiotic FX856 interacts with the gut and immune system to reduce inflammation. A 2-way crossover intervention study will be conducted with FX856 (4 weeks) in an overweight and obese population, as such individuals are likely to have chronic mild gut inflammation and examine markers of faecal calprotectin and circulating inflammatory markers.

Inclusion Criteria:

• Either a BMI 25+ kg/m2 and be aged 40+ years or have a BMI 30+ kg/m2 and aged 18+ years
• Males and females (not currently pregnant/lactating)
• Omnivorous diet (consuming plant & animal based foods)
• Not taking any medication affecting the gastro-intestinal tract
• No chronic gastro-intestinal illness
• Not using fibre supplements or any probiotic or prebiotic products, e.g., Fybogel, Actimel, kefir or kimchee for at least 6 weeks prior to study
• Not consuming 7+ units of alcohol per day (e.g. 3 medium glasses of wine ~12%)

Exclusion Criteria:

• Not aged 40+ years (if have a BMI 25-29.9 kg/m2)
• BMI<30 kg/m2 (if aged 18-39 years)
• Pregnant/lactating female
• Vegan/vegetarian/high protein diet
• Chronic gastro-intestinal illness
• Taking medication affecting the gastro-intestinal tract
• Taking fibre supplements or any probiotic or prebiotic products
• Consuming 7+ units of alcohol per day (e.g. 3 medium glasses of wine ~12%)

Double blinded to participants and researchers