Action of different bran preparations on colonic function.

Two different types of commercially available bran were studied. One of these was composed of flake-like particles (coarse bran) whereas the other had smaller, finer particles with a floury component (fine bran). The effectiveness of the two preparations in lowering intraluminal pressure and decreasing transit time in patients with constipation and diverticular disease was assessed. Only coarse bran promoted changes at the dose used. The physical properties of the brans were examined in an effort to explain their differing effects. It is concluded that water-holding capacity, upon which the beneficial effect of bran may depend, is a function of particle size. The greater water-holding capacity of coarse bran makes it preferable for the treatment of colonic disorders.