What is a Probiotic?
A preparation, often in capsule or powder-form, which contains viable bacteria (and sometimes yeasts). Once swallowed, the bacteria then either adhere to and colonise the mucus that lines the gut, or simply passes through the gut as a transient messenger.
When to use Probiotics?
Probiotics are extremely useful in the treatment of gut problems when used appropriately. Most people however, when buying an over-the-counter probiotic, are usually just doing guess work. This explains why this approach can improve gut health in some people, but can actually worsen symptoms in others.
Most humans do have major imbalances in their gut bacteria (see Gut microbiome for further information). There are trillions of bacteria living in the gut, and therefore only an advanced stool analysis which specifically identifies deficiencies and overgrowth of these bacteria can guide judicious probiotic use.