Claro, la celulosa no se digiere, es la fibra, pero al expulsarla eliminamos deshechos, o sea que es bueno y necesario consumirla.
Aquí está explicado:
In fact, few
organisms possess enzymes that can digest cellulose. Humans
do not; the cellulose in our food passes through the digestive
tract and is eliminated with the feces. Along the way, the cellulose
abrades the wall ofthe digestive tract and stimulates the
lining to secrete mucus, which aids in the smooth passage of
food through the tract. Thus, although cellulose is not a nutri·
ent for humans, it is an important part ofa healthful diet. Most
fresh fruits, vegetables, and whole grains are rich in cellulose.
On food packages, uinsoluble fiber~ refers mainly to cellulose.
Some prokaryotes can digest cellulose, breaking it down
into glucose monomers. A cow harbors cellulose·digesting
prokaryotes in its rumen, the first compartment in its stomach
(figure 5.9). The prokaryotes hydrolyze the cellulose of hay
and grass and convert the glucose to other nutrients that nourish
the cow. Similarly, a termite, which is unable to digest cellulose
by itself, has prokaryotes living in its gut that can make a
meal of wood. Some fungi can also digest cellulose, thereby
helping re<ycle chemical elements within Earth's e<osystems
Las vacas digieren la celulosa porque tienen en el estómago unas bacterias que hacen ese trabajo.
La fuente es fiable (es de un libro de biología). Espero que sirva de ayuda.
