Resistant starch lowers fecal concentrations of ammonia and phenols in humans

Anne Birkett, Jane Muir, Jodi Phillips, Gwyn Jones, Kenn O'Dea

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Abstract

We investigated the effect of resistant starch (RS) on markers of colonic protein metabolism. Eleven subjects participated in a randomized crossover study in which they consumed either high-RS (39 ± 3 g/d, χ̄ ± SEM) or low-RS (5 ± 0.4 g/d) diets for 3 wk. All other macronutrients were kept constant. During the high-RS diet daily excretion 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 to 5.3 ± 0.8 mg/d/P < 0.01). Fecal concentrations of ammonia decreased from 397 ± 33 to 278 ± 49 μg/g (P < 0.01) and phenols decreased from 69 ± 8 to 39 ± 10 μg/g (P < 0.001). Daily output of urinary ammonia, urea, phenols, and total nitrogen did not change significantly, but pH decreased from 6.4 ± 0.1 to 6.2 ± 0.1 (P < 0.05) during the high-RS period. These results suggest that RS significantly attenuates the accumulation of potentially harmful byproducts of protein fermentation in the human colon.

Original languageEnglish
Pages (from-to)766-772
Number of pages7
JournalThe American Journal of Clinical Nutrition
Volume63
Issue number5
DOIs
Publication statusPublished - May 1996
Externally publishedYes

Keywords

  • ammonia
  • colon
  • feces
  • fermentation
  • nitrogen
  • phenols
  • protein
  • Resistant starch
  • urine

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