Lupin kernel fibre foods improve bowel function and beneficially modify some putative faecal risk factors for colon cancer in men

Abstract

Consumption of some dietary fibres may benefit bowel health; however, the effect of Australian sweet lupin (Lupinus angustifolius) kernel fibre (LKFibre) is unknown. The present study examined the effect of a high-fibre diet containing LKFibre on bowel function and faecal putative risk factors for colon cancer compared to a control diet without LKFibre. Thirty-eight free-living, healthy men consumed an LKFibre and a control diet for 1 month each in a single-blind, randomized, crossover study. Depending on subject energy intake, the LKFibre diet was designed to provide 17–30g/d fibre (in experimental foods) above that of the control diet. Bowel function self-perception, frequency of defecation, transit time, faecal output, pH and moisture, faecal levels of SCFA and ammonia, and faecal bacterial β-glucuronidase activity were assessed. In comparison to the control diet, the LKFibre diet increased frequency of defecation by 0·13 events/d (P=0·047), increased faecal output by 21% (P=0·020) and increased faecal moisture content by 1·6% units (P=0·027), whilst decreasing transit time by 17% (P=0·012) and decreasing faecal pH by 0·26 units (P<0·001). Faecal butyrate concentration was increased by 16% (P=0·006), butyrate output was increased by 40% (P=0·002)and β-glucuronidase activity was lowered by 1·4μmol/h per g wet faeces compared to the control diet (P<0·001). Addition of LKFibre to the diet incorporated into food products improved some markers of healthy bowel function and colon cancer risk in men.