Whilst fruits and vegetables are an essential part of our dietary intake, the role of fiber in the prevention of colorectal diseases remains controversial. The main feature of a high-f iber diet is its poor digestibil...Whilst fruits and vegetables are an essential part of our dietary intake, the role of fiber in the prevention of colorectal diseases remains controversial. The main feature of a high-f iber diet is its poor digestibility. Soluble fiber like pectins, guar and ispaghula produce viscous solutions in the gastrointestinal tract delaying small bowel absorption and transit. Insoluble f iber, on the other hand, pass largely unaltered through the gut. The more fi ber is ingested, the more stools will have to be passed. Fermentation in the intestines results in build up of large amounts of gases in the colon. This article reviews the physiology of ingestion of fiber and defecation. It also looks into the impact of dietary fiber on various colorectal diseases. A strong case cannot be made for a protective effect of dietary fi ber against colorectal polyp or cancer. Neither has fi ber been found to be useful in chronic constipation and irritable bowel syndrome. It is also not useful in the treatment of perianal conditions. The fiber deficit -diverticulosis theory should also be challenged. The authors urge clinicians to keep an open mind about fi ber. One must be aware of the truths and myths about fi ber before recommending it.展开更多
AIM:To evaluate prospectively usefulness of fecal lactoferrin(Lf)and fecal hemoglobin(Hb)in the diagnosis of colorectal diseases.METHODS:Fecal Lf and Hb were measured using ELISA in 872 patients before they underwent ...AIM:To evaluate prospectively usefulness of fecal lactoferrin(Lf)and fecal hemoglobin(Hb)in the diagnosis of colorectal diseases.METHODS:Fecal Lf and Hb were measured using ELISA in 872 patients before they underwent colorectal endoscopy.RESULTS:Lf was positive in 18(50%)of 36 patients with colorectal cancer,25(15.9%)of 157 with colorectal polyps,29(46.8%)of 62 with ulcerative colitis,and 25(62.5%)of 40(62.5%)with Crohn's disease.The Hb-positive rates were 50%,12.1%,41.9% and 32.5%,respectively.Of the 318 patients free of abnormalities by colorectal endoscopy,Lf was positive in 29(9.1%)and Hb was positive in 15(4.7%).Among patients with Crohn's disease,the Lf-positive rate was significantly higher than the Hb-positive rate.If either high Lf or Hb levels were considered positive,the positive rates rose to 61.1%,51.6%,and 67.5% in the colorectal cancer group,ulcerative colitis group,and Crohn's disease group,respectively.If both high Lf and Hb levels were rated positive,the positive predictive values(PPV)were 21% for colorectal cancer,33% for ulcerative colitis,and 17% for Crohn's disease,and PPV of high Hb level alone was 18%,25% and 13%,respectively.CONCLUSION:Fecal Lf and Hb were found useful in the detection of colorectal diseases,and the combination of the two measurements appears to increase the sensitivity and efficacy of diagnosis.展开更多
文摘Whilst fruits and vegetables are an essential part of our dietary intake, the role of fiber in the prevention of colorectal diseases remains controversial. The main feature of a high-f iber diet is its poor digestibility. Soluble fiber like pectins, guar and ispaghula produce viscous solutions in the gastrointestinal tract delaying small bowel absorption and transit. Insoluble f iber, on the other hand, pass largely unaltered through the gut. The more fi ber is ingested, the more stools will have to be passed. Fermentation in the intestines results in build up of large amounts of gases in the colon. This article reviews the physiology of ingestion of fiber and defecation. It also looks into the impact of dietary fiber on various colorectal diseases. A strong case cannot be made for a protective effect of dietary fi ber against colorectal polyp or cancer. Neither has fi ber been found to be useful in chronic constipation and irritable bowel syndrome. It is also not useful in the treatment of perianal conditions. The fiber deficit -diverticulosis theory should also be challenged. The authors urge clinicians to keep an open mind about fi ber. One must be aware of the truths and myths about fi ber before recommending it.
文摘AIM:To evaluate prospectively usefulness of fecal lactoferrin(Lf)and fecal hemoglobin(Hb)in the diagnosis of colorectal diseases.METHODS:Fecal Lf and Hb were measured using ELISA in 872 patients before they underwent colorectal endoscopy.RESULTS:Lf was positive in 18(50%)of 36 patients with colorectal cancer,25(15.9%)of 157 with colorectal polyps,29(46.8%)of 62 with ulcerative colitis,and 25(62.5%)of 40(62.5%)with Crohn's disease.The Hb-positive rates were 50%,12.1%,41.9% and 32.5%,respectively.Of the 318 patients free of abnormalities by colorectal endoscopy,Lf was positive in 29(9.1%)and Hb was positive in 15(4.7%).Among patients with Crohn's disease,the Lf-positive rate was significantly higher than the Hb-positive rate.If either high Lf or Hb levels were considered positive,the positive rates rose to 61.1%,51.6%,and 67.5% in the colorectal cancer group,ulcerative colitis group,and Crohn's disease group,respectively.If both high Lf and Hb levels were rated positive,the positive predictive values(PPV)were 21% for colorectal cancer,33% for ulcerative colitis,and 17% for Crohn's disease,and PPV of high Hb level alone was 18%,25% and 13%,respectively.CONCLUSION:Fecal Lf and Hb were found useful in the detection of colorectal diseases,and the combination of the two measurements appears to increase the sensitivity and efficacy of diagnosis.
