British Journal of Nutrition

Full Papers

Human and Clinical Nutrition

Ability of a high-total antioxidant capacity diet to increase stool weight and bowel antioxidant status in human subjects

Marta A. Bianchia1, Francesca Scazzinaa1, Daniele Del Rioa1, Silvia Valtueñaa2, Nicoletta Pellegrinia1, Laura Franzinia2, Maria Luisa Callegaria3, Claudia Pellacania4, Annamaria Buschinia4, Ivana Zavaronia2 and Furio Brighentia1 c1

a1 Department of Public Health, University of Parma, Via Volturno 39, 43100 Parma, Italy

a2 Department of Internal Medicine and Biomedical Sciences, University of Parma, Parma, Italy

a3 Centro Ricerche Biotecnologiche (CRB), Cremona, Italy

a4 Department of Genetics, Biology of Microorganisms, Anthropology, Evolution, University of Parma, Parma, Italy


There is limited knowledge about the possible effect of unabsorbed dietary antioxidants that reach the large intestine on bowel habits. The aim of the present study was to investigate whether a dietary recommendation directed to increase diet total antioxidant capacity (TAC) is able to affect gut function in human subjects. In this cross-over intervention, nineteen subjects followed a high-TAC (HT) and a low-TAC (LT) diet for 2 weeks, which were comparable for energy, macronutrient, total dietary fibre and alcohol contents. At the end of each intervention period, the 48 h stool output was recorded. In the faecal samples obtained from a subset of nine subjects, moisture, pH, ammonia content, Lactobacillus and Bifidobacterium counts, faecal water antioxidants and genotoxicity were measured. A 3 d weighed food record was used to assess the diet composition during HT and LT diet intake. Significant increases in the intake of TAC, vitamins E and C and phenolic compounds were observed during the HT diet intake. The higher intake of antioxidants led to increased 48 h stool output (324 (sd 38) g in HT v. 218 (sd 22) g in LT), and to higher TAC and total phenolic concentrations in faecal water. No significant variation in the other measured parameters was observed between the diets. In conclusion, a diet selected to raise the intake of dietary antioxidants is able to increase stool bulk and antioxidant content of faeces.

(Received January 28 2010)

(Revised May 17 2010)

(Accepted May 20 2010)

(Online publication June 28 2010)


c1 Corresponding author: F. Brighenti, fax +39 0521 903832, email


Abbreviations: HT, high-total antioxidant capacity; LT, low-total antioxidant capacity; RT-PCR, real-time PCR; TAC, total antioxidant capacity; WO, wash-out