Summary points
• Microflora of the large intestine complete digestion through fermentation, protect against pathogenic bacteria and stimulate development of the immune system
• Probiotics and prebiotics in the diet can modify the composition and some metabolic activities of the microflora
• Probiotics are generally the live micro-organisms in foods such as yoghurts; they survive passage through the gut and temporarily bring the benefits of the normal gut flora
• Probiotics have been used to treat or prevent diarrhoea and to improve symptoms in lactose intolerance
• Prebiotics are non-digestible oligosaccharides that can stimulate selectively the growth of probiotic-like bacteria normally present in the gut
• Many claims for the potential health benefits of prebiotics remain unproved