Colonic production of butyrate in patients with previous colonic cancer during long-term treatment with dietary fibre (Plantago ovata seeds).

BACKGROUND: Butyrate has antineoplastic properties against colorectal cancer cells and is the preferred oxidative substrate for colonocytes. Like acetate and propionate (short-chain fatty acids; SCFAs), butyrate is produced by colonic fermentation of dietary fibre.
METHODS: Twenty patients resected for colorectal cancer were treated with 20 g/day of the fibre Plantago ovata seeds for 3 months, which increased the intake of fibre by 17.9 +/- 0.8 g/day, from basal levels of 19.2 +/- 1.7 g/day; 17 patients completed the study. Faecal samples were obtained on eight occasions, twice before treatment, and monthly three times during and three time after treatment.
RESULTS: One month of fibre therapy increased faecal concentrations of butyrate by 42 +/- 12% (from 13.2 +/- 1.2 to 19.3 +/- 3.0 mmol/l; P < 10(-4)), acetate by 25 +/- 6% (P < 10(-4)), propionate by 28 +/- 9% (P = 0.01), and total SCFAs by 25 +/- 6% (P < 10 (-4)). Concentrations were increased during the 3-month fibre treatment but reversed to pretreatment levels within 1 to 2 months after cessation of fibre supplementation. The relative concentration (ratio) of butyrate was not altered owing to a simultaneous increase in acetate and propionate. Faecal pH decreased initially but was normalized after 2 months of fibre supplements. Fibre therapy increased the 24-h productions of butyrate by 47 +/- 10% (P < 10(-4)) and acetate by 50 +/- 7% (P < 10(-4)) in 16.6% faecal homogenates with added P. ovata seeds (20mg/ml), but SCFA productions returned to pretreatment levels after discontinuation of additional fibre intakes.
CONCLUSIONS: Oral intake of P. ovata seeds adapted the colonic flora to increase the production of butyrate (and acetate) from this fibre and increased faecal concentrations of butyrate by 42% in patients resected for colonic cancer. The effects depended on continuity of treatment.