Probiotics have become increasingly popular and are now credited with a wide range of benefits.
Probiotics are best defined as live viable micro-organisms that, when taken by mouth, exert beneficial effects on the host.1 Requirements for an organism to act as a probiotic include acid stability and ability to colonise the intestine. Some of the most commonly used probiotics are organisms belonging to the lactobacilli group of lactase-producing bacteria, such as Lactobacillus acidophilus. Other organisms with probiotic effects include the bacteria Bifidobacterium and nonpathogenic Escherichia coli, and the yeast Saccharomyces boulardii. Probiotics are often used alone, but may be combined with prebiotics (inactive food components that assist in the growth of beneficial micro-organisms in the gut); the probiotic and prebiotic are then known as synbiotics.