All sugar is not the same. In fact, some sugars play very important
roles in intercellular interactions. Gut bacteria is an example of one
of these. They eat fucose (one of these special functional sugars) in
the gut (fucose is what gives the gut lining its mucusy feel) and then
incorporate the sugar into their own cell surfaces. The immune system,
then, does not see these bacteria as a threat and does not respond. Two
very interesting articles.