Introduction: Experimental evidence suggests dietary butyrylated high amylose maize starch (HAMSB) may reduce the risk of colorectal cancer (CRC) in rats (1;2). HAMSB delivered butyrate to the colon of humans (3) and ingestion of 40 g/day increased faecal butyrate concentration in healthy adults (4). A Cancer Council Multi-State Research Grant was awarded to investigate the effects of HAMSB, a novel dietary chemopreventative agent, on polyposis in familial adenomatous polyposis (FAP) participants. The aim of this pilot study was to determine if esterified butyrate is released by the reduced large bowel microbiota of FAP with ileo-rectal anastomosis (IRA), or ileal pouch anal-anastamosis (IPAA).
Methods: Five participants with IRA and three with IPAA were randomly assigned to one of six treatment sequences consuming 2.5, 10 or 20 g HAMSB twice daily for 14 days. There was a seven day washout between each dose period. Faeces were collected (24 hours) at baseline and day 13. Participants completed questionnaires assessing the effects of the starch on their gastrointestinal function and quality of life at baseline and end of each dose period.
Results: The starch was well tolerated and did not negatively affect gastrointestinal function at any level of intake. Faecal butyrate concentration increased with intakes of 20 and 40 g HAMSB/day in participants with IRA and IPAA. Faecal pH tended to decrease at the higher HAMSB intakes. The faecal output per day, moisture and ammonia concentrations were not affected by amount of HAMSB consumed.
Conclusions: This study confirms that a significant proportion of ingested esterified butyrate is released by the large bowel microflora in FAP with IRA and IPAA and supports the selection of this well recognised model of sporadic CRC for testing the efficacy of HAMSB and other potential CRC chemo-preventative agents that require an active microbiota to promote their bioavailability.