The effect of wheat bran upon bile salt metabolism and upon the lipid composition of bile in gallstone patients

When raw wheat bran was added to the diet of six subjects for 4–6 weeks, chenodeoxycholate (CDC) synthesis increased from 0.46±0.12 to 0.57±0.17 mmol/day (P<0.025), and the CDC pool increased from 1.72±0.47 to 2.19±0.74 mmol (P<0.05). Deoxycholate (DC) pool size diminished from 1.20±0.29 to 0.80±0.16 mmol, but cholate synthesis and pool size were unaffected. Overall, the size of the bile salt pool did not change. In spite of this, when 10 patients with probable cholesterol gallstones took bran supplements for 4–6 weeks, their gallbladder bile aspirated from the duodenum became less saturated with cholesterol. The molar percentage of cholesterol fell from 10.1±3.1% to 8.6±2.7% (P<0.01), and the saturation index of bile fell from 1.49±0.40 to 1.29±0.38 (P<0.005). Bran probably operates primarily on the colon, reducing the formation or absorption of the bacterial metabolite DC, a substance which impairs CDC synthesis.This work was supported by grants from the British Council, the United Bristol Hospitals and the Kellogg Company of Great Britain Limited.