RESISTANT STARCH LOWERS FECAL CONCENTRATIONS OF AMMONIA AND PHENOLS IN HUMANS

We investigated the effect of resistant starch (RS) on markers of colo nic protein metabolism. Eleven subjects participated in a randomized c rossover study in which they consumed either high-RS (39 +/- 3 g/d, (x ) over bar +/- SEM) or low-RS (5 +/- 0.4 g/d) diets for 3 wk. All othe r macronutrients were kept constant. During the high-RS diet daily exc retion of fecal nitrogen increased from 1.84 +/- 0.15 to 2.86 +/- 0.42 g/d (P < 0.01) and excretion of fecal phenols fell from 9.2 +/- 1.4 t o 5.3 +/- 0.8 mg/d (P < 0.01). Fecal concentrations of ammonia decreas ed from 397 +/- 33 to 278 +/- 49 mu g/g (P < 0.01) and phenols decreas ed from 69 +/- 8 to 39 +/- 10 mu g/g (P < 0.001). Daily output of urin ary ammonia, urea, phenols, and total nitrogen did not change signific antly, but pH decreased from 6.4 +/- 0.1 to 6.2 +/- 0.1 (P < 0.05) dur ing the high-RS period, These results suggest that RS significantly at tenuates the accumulation of potentially harmful byproducts of protein fermentation in the human colon.