The Effect of Butyrylated Starch on Bowel Polyps in Familial Adenomatous Polyposis: Results of a Randomized, Double-blind, Placebo-Controlled Crossover Trial.

UNLABELLED: Butyrate may reduce the risk of colorectal cancer and can be delivered to the colon using butyrylated high-amylose maize starch (HAMSB). This trial evaluated the effects of HAMSB on polyp burden in participants with familial adenomatous polyposis. This study was a randomized, double-blind, placebo-controlled crossover trial. In three 6-month periods, participants ingested 40 g/day of HAMSB or low-amylose starch, followed by the alternative, and then a washout. Participants underwent four video-recorded colonoscopies to assess polyp burden as the primary endpoint. At baseline, two distal bowel tattoos were placed: tattoo one where polyps were cleared at each scope and tattoo two where polyps were left in situ. Generalized linear mixed models were used to estimate the ratio of mean polyp counts in intervention compared with placebo periods. Seventy-two participants were randomized (33 female), with 49 completing the study. In the intention-to-treat analysis, HAMSB did not reduce mean global [0.9 fold change (FC); 95% confidence interval (CI), 0.77-1.06; P = 0.218] or small (<2.4 mm) polyp numbers (0.88 FC; 95% CI, 0.71-1.1; P = 0.267). There was a trend for the reduction of small polyps in tattoo one (0.72 FC; 95% CI, 0.5-1.03; P = 0.074). In the per-protocol analysis, there was a strong trend for HAMSB to reduce mean global small polyp numbers (0.79 FC; 95% CI, 0.62-1; P = 0.051). HAMSB may reduce polyp initiation in the distal bowel without causing regression or growth of existing polyps. However, 95% CIs indicate large uncertainty to the true direction of the treatment effect, and the P values provide only weak evidence against the null hypothesis of no treatment effect.

PREVENTION RELEVANCE: There is convincing evidence that dietary fiber reduces the risk of colorectal cancer possibly by production of butyrate during microbial fermentation of indigestible fiber. This study was designed to determine if a dietary supplement that delivers butyrate to the colon reduces polyp burden in participants with familial adenomatous polyposis.