The most commonly studied prebiotics are inulin, fructo-oligosaccharides (FOS), galacto-oligosaccharides (GOS), and human milk oligosaccharides (HMOs).22

Inulin is the name given to the range of carbohydrate-based fructose polymers or polysaccharides commonly found in plants and widely used as a food ingredient. Oligofructose is a subgroup of inulin, neither of which are digested in the upper intestine. However, in the lower intestine they stimulate growth of bifidobacteria, increase calcium absorption, increase faecal weight, speed up the gastrointestinal transit time, and possibly reduce lipid levels.3,25

Foods which contain prebiotic compounds include leeks, garlic, onions, soybean, chicory, asparagus, bananas, artichokes, wheat, and oats, and possibly some honeys.26

Irritable bowel syndrome (IBS) management can include recommending a low FODMAPS diet – Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols. Around three quarters of people with IBS may find symptoms improve if they reduce their consumption of certain food types which contains FODMOPS – many of which contain prebiotics.27

Removing gluten from the diet can decrease Bifidobacterium and Lactobacillus levels, while E. coli and Enterobacteriaceae levels increase along with a risk of opportunistic infection from other bacteria. This may have implications for people with coeliac disease as well as ‘healthy’ people following gluten-free diets.6