Effect of wheat fiber and vitamins C and E on rectal polyps in patients with familial adenomatous polyposis

J Natl Cancer Inst. 1989 Sep 6;81(17):1290-7. doi: 10.1093/jnci/81.17.1290.


Over a 4-year period in a chemoprevention trial on large bowel neoplasia, 58 patients with familial adenomatous polyposis were treated with 4 g of ascorbic acid (vitamin C)/day plus 400 mg of alpha-tocopherol (vitamin E)/day alone or with a grain fiber supplement (22.5 g/day). In this randomized, double-blind, placebo-controlled study, we determined the effects of these supplements on rectal polyps in these patients. Analysis by intent to treat suggested that the high-fiber supplement had a limited effect. Analysis adjusted for patient compliance showed a stronger benefit from the high-fiber supplement during the middle 2 years of the trial. The results provide evidence for inhibition of benign large bowel neoplasia by grain fiber supplements in excess of 11 g/day in this study population. The findings are consistent with the hypothesis that dietary grain fiber and total dietary fat act as competing variables in the genesis of large bowel neoplasia.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenomatous Polyposis Coli / complications*
  • Adult
  • Ascorbic Acid / therapeutic use*
  • Clinical Trials as Topic
  • Diet
  • Dietary Fiber / adverse effects
  • Dietary Fiber / therapeutic use*
  • Double-Blind Method
  • Humans
  • Patient Compliance
  • Placebos
  • Polyps / diet therapy*
  • Polyps / drug therapy
  • Polyps / etiology
  • Random Allocation
  • Rectal Diseases / diet therapy*
  • Rectal Diseases / drug therapy
  • Rectal Diseases / etiology
  • Triticum*
  • Vitamin E / therapeutic use*


  • Dietary Fiber
  • Placebos
  • Vitamin E
  • Ascorbic Acid