Prebiotics and IL

If probiotic comes from the ancient Greek and means "in favour of life", prebiotic still comes from Greek and means "before life".

Prebiotics are substances (not microorganisms!) that pass un-modified through the bowel. This means that our body does not modify them, while bacteria in the bowel do .

Basically, prebiotics are substances that our bodies don't eat but that our bacteria do eat. Plus, intestinal bacteria get their energy from sugars that are “leftover” because we can not digest them and from our own mucus.

Prebiotics selectively feed the growth of healthy intestinal bacteria (such as bifidobacteria and lactobacilli) at the expense of the less friendly putrefactive bacteria (such as bacteroides, clostridia, and other coliforms).

If we don't feed probiotics with prebiotics, even if we supplement our diet with probiotics, it will not be enough. This is the basic reason for functional food industry is going toward the commercialization of synbiotic food, having both pre- and probiotics.

Prebiotics are oligosaccharides, that is sugars "bigger" than normal sugar but "smaller" than starch.

The main prebiotics are:

*fructooligosaccharides (FOS), normally found in Jerusalem artichoke tubers, dandelion root, burdock root, onions, leeks, some grains, garlic, wheat, bananas, asparagus, tomatoes, yacon, raisins, prunes and honey;
*galattooligosaccharides (GOS), normally found in human milk (and some humanized baby formula, especially in the EU);
*inulin, normally found in dahlia tubers, burdock roots, chicory roots and greens.

Interestingly, bacterial species differ in the types of sugars required for growth. Bifidobacteria grew well on FOSs and inulin, while lactobacilli grow poorly on these sugars.

The by-products of the metabolism of these sugars are primarily short-chain fatty acids, which are considered to be "food" for the bowel cells in the colon.

Coming to IL, why is it all so interesting?

Because among the several aspects affecting the gut microflora, high levels of fat in the stool as well as high level of proteins can negatively affect the level of Bifidobacteria.