For some reason, I get these two confused. Both are food ingredients designed to improve the health of your colonic microflora. Probiotics are the live cultures of Lactobacillus spp that are commonly found in yoghurt. The idea is that the healthy bacteria will survive and when they reach the colon, grow as part of the microflora, prevent harmful bacteria from colonizing the colon and causing diarrhea or worse.
Prebiotics are food ingredients, especially inulin, which are not digested by our own enzymes so reach the colon mostly intact. These compounds are then digested by the colonic microflora to produce short chain fatty acids, which in turn are energy sources for both gut microbes and the cells lining the lumen of the colon. Inulin and other soluble fibres are thought to encourage populations of healthy bacteria.
An interesting story I remember from undergraduate nutrition was that Jerusalem artichokes, which contain inulin in the way white potatoes contain starch, were grown by the British government during World War 1 to feed the troops in France. Unfortunately, the powers-that-be did not realise that inulin was not digested like starch and eating large quantities of Jerusalem artichokes has an unfortunate effect on soldiers’ moral 😉
Adding prebiotics, such as inulin or beta-glucan, to food containing probiotics may help the probiotics survive storage. So does that make them preprobiotics?