I-fiber yokudla iwuhlobo lokudla olungenakuhlukaniswa ngama-enzyme wokugaya umzimba womuntu, alukwazi ukumuncwa umzimba wezinto ze-polysaccharide kanye negama elijwayelekile le-lignin.
Nakuba kunomehluko osobala ngamaprotheni, amafutha, amavithamini nezinye izakhi, kubaluleke kakhulu empilweni yomuntu, kuze kube yiminyaka yawo-1970, i-fiber yokudla yafakwa ngokusemthethweni emphakathini wokudla okunomsoco, obizwa ngokuthi "isakhi sesikhombisa", bese imakethe ikhombisa umkhuba omuhle wokukhula.