Medical Aspects of Dietary Fiber

ISBN-13: 9781461591788 / Angielski / Miękka / 2012 / 300 str.

Gene A. Spiller

Opis

Dietary therapy has always been important to medical practice even if it has more often been sacramental than physiological in effect. "You are what you eat" meant a lot to primitive tribes whose new leader had to eat part of his predecessor, and giving diets brought out the priest in the physician even if he or she had heard that "nothing that enters into a man defiles a man. " What people eat began to take on new meaning, however, a generation ago when Schoenheimer and others made clear that body fat and muscle protein were not the sluggish unchanging masses they had appeared but instead were store- houses of energy and material influenced by food, activity, and metabolic pro- cesses. Fiber, or residue as it was then still called, however, seemed unimpor- tant; even the gastroenterologist concerned with keeping the bowels open by three cooked fruits, three cooked vegetables, and twelve glasses of water each day sometimes felt like a shaman if his cure for constipation worked. Nobody any longer read Arbuthnot Lane's charming Victorian book, The Way Out, which placed the blame for most human ailments on constipation; Lane even removed the bowel to cure the costive ills. Burkitt revived a scientific interest in fiber and the possible connection between diet. constipation, and many physical disorders by observing the vol- ume and frequency of stools on an African diet and on an English diet.

Spis treści

1. Effect of Fiber on Colon Function.- I. Introduction.- II. Physicochemical Effects of Fiber.- A. Water-Holding Capacity.- B. Determinants of Stool Weight.- C. Cation-Exchange Properties.- D. Adsorption and Excretion of Bile Acids.- E. Fecal Bile Acids and Neutral Sterols.- F. Matrix Formation.- G. Effect of Fiber on Bacteria.- III. Metabolism of Dietary Fiber in the Colon.- IV. Effect of Dietary Fiber Metabolism on Colon function.- V. Effect of Fiber on Stool Weight.- A. Normal Fecal Weight.- B. Addition of Wheat Bran to the Diet.- C. Addition of Fruit and Vegetables to the Diet.- VI. Summary.- References.- 2. The Measurement of Intestinal Transit Time.- I. Introduction.- II. Physiological Relationships.- III. Methods of Measuring Gastrointestinal Transit.- A. Gastric Emptying Time.- B. Small-Intestinal Transit Time.- C. Cecal Residence Time.- D. Total or Transintestinal Transit Time.- E. Modification by Fiber.- F. Colonic Transit Time.- G. Differential Colonic Transit Time.- H. Mean Transit Time.- IV. Transit in Relation to Other Functions.- A. Relation to Pressure.- B. Relation to Fecal Weight.- C. Hormonal and Metabolic Influences.- D. Changes in Colonic Disease.- V. Conclusions.- References.- 3. Dietary Fiber in Diverticular Disease of the Colon.- I. Introduction.- II. Fiber Intake and the Prevalence of Diverticular Disease.- A. Geographical Distribution.- B. Historical Changes in Prevalence.- C. Comparisons between Individuals in a Single Community.- III. Diverticular Disease: Pathogenesis and the Effect of Fiber.- A. Pathogenesis.- B. Effects of Dietary Fiber on the Normal Colon.- C. Dietary Fiber Depletion.- IV. Fiber Depletion Studies in Animals.- V. Treatment of Diverticular Disease with Dietary Fiber.- A. Treating Symptoms.- B. Preventing Complications.- VI. Conclusions.- References.- 4. Effects of Dietary Fiber on the Structure and Function of the Small Intestine.- I. Introduction.- II. Dietary Effects on Small-Bowel Structure.- III. Dietary Effects on Small-Bowel Microbiology.- IV. Relationship between Intestinal Flora and Mucosal Structure and Function.- V. Summary.- References.- 5. Colon Cancer: The Emergence of a Concept.- I. Epidemiological Features.- A. Worldwide Distribution.- B. Pathological Relationships.- C. Conclusions from Epidemiological Evidence.- II. The High-Fat, Low-Fiber Hypothesis.- A. Consistency of the Hypothesis with Epidemiological Evidence.- B. Practical Considerations.- References.- 6. Experimental Animal Studies in Colonic Carcinogenesis and Dietary Fiber.- I. Introduction.- II. General Concepts and Rationale.- III. Experimental Colonic Neoplasia: The Model.- A. Background.- B. Chemically Induced and Spontaneous Neoplasia.- C. Metabolism and Action of Hydrazines.- D. Potential Relevance of Hydrazines to Humans.- E. Biological Aspects of Experimental Intestinal Neoplasia.- F. Summary of the Model System.- IV. Studies with Dietary Fiber in Experimental Colonic Neoplasia.- A. Background.- B. Studies with Mixtures of Individual Fiber Polymers.- C. Studies Examining Single Fibers.- V. Future Directions and Mechanisms of Fiber Action.- A. Background and Physiochemical Properties of Fiber Polymers.- B. Water-Holding Capacities of Fiber.- C. Fiber Adsorption of Organic and Inorganic Compounds.- D. Fiber and Intestinal Transit.- E. Fiber and Bile-Acid Metabolism.- F. Fiber and Intestinal Microflora.- G. Fiber in Anticarcinogenesis.- VI. Conclusion.- References.- 7. Epidemiology of Colon Cancer: Fiber, Fats, Fallacies, and Facts.- I. Introduction.- II. Disease Distribution.- A. Migrant Populations.- B. Etiology.- III. Correlational Studies.- IV. Case-Control Studies.- A. The Working Model-A “Jigsaw Puzzle”.- B. Prospects.- References.- 8. Dietary Fiber and Lipid Metabolism: An Update.- I. Introduction.- II. Working Hypothesis.- III. Evaluation of Hypothesis.- A. Adsorption of Bile Acids and Salts.- B. Lipid Metabolism.- C. Other Possible Mechanisms.- D. Effects on Experimental Atherosclerosis.- V. Conclusions.- References.- 9. Dietary Fiber: Effects on Plasma and Biliary Lipids in Man.- I. Introduction.- II. Epidemiological Studies.- A. Non-Westernized Populations.- B. Western Populations.- III. Clinical Studies.- A. Plasma Lipids and Lipoproteins.- B. Effects of Dietary Fiber on Bile Composition in Man.- IV. Mechanisms.- A. Displacement of Saturated Fat, Cholesterol.- B. Energy Balance, Nutrient Absorption.- C. Cholesterol Absorption and Fecal Steriod Excretion.- D. Other Mechanisms.- V. Clinical Significance of Dietary Fibers.- A. Pharmacological Applications.- B. Dietary Significance.- References.- 10. Dietary Fiber and Carbohydrate Metabolism.- I. Introduction.- II. Dietary Fiber and Carbohydrate Tolerance Tests.- III. Fiber Foods and Fiber Pharmacology.- IV. Mechanisms of Action of Fiber in Relation to Carbohydrate Metabolism.- A. Importance of Viscosity.- B. Reduction of Insulin Response.- C. Slow Absorption Rather Than Malabsorption.- D. Gastric Emptying and Small-Intestinal Absorption.- E. Rate Phenomenon.- V. Prerequisites for Maximum Effectiveness.- A. High-Starch Diets.- B. Intimate Mixing with Carbohydrate Foods.- VI. General Considerations.- A. Effect of One Fiber Meal on the Next.- B. Long-Term Effect of Dietary Fiber.- VII. Conclusion.- References.- 11. Dietary Fiber and Diabetes.- I. Introduction.- A. Therapeutic Potential of Dietary Fiber.- B. Dietary Fiber and the Prevalence of Diabetes.- II. Short-Term Effects of Fiber.- A. Fiber Supplements.- B. High-Fiber Diets.- III. Long-Term Effects of Fiber.- A. Fiber Supplements.- B. High-Fiber Diets.- IV. Proposed Mechanisms.- A. Glucose Metabolism.- B. Lipid Metabolism.- V. Therapeutic Use of High-Fiber Diets.- A. Diabetes Mellitus.- B. Reactive Hypoglycemia.- C. Hypercholesterolemia.- D. Hypertriglyceridemia.- VI. Conclusions.- References.- 12. Food Intake Regulation and Fiber.- I. Introduction.- II. Work and Rate of Ingestion.- III. Energy Density.- IV. Satiety.- V. Long-Term Studies.- VI. Insulin Release and the Rate and Site of Nutrient Absorption.- VII. Fecal Energy Loss.- VIII. Epidemiological Evidence.- IX. Animal Obesity.- X. Palatability.- A. Special Note on Sugar.- B. Sugar and Obesity.- XI. Fiber and Treatment of Obesity.- XII. Summary.- References.- 13. Dietary Fiber and Mineral Absorption.- I. Introduction.- II. Calcium Absorption and Calcium Balance.- A. The Role of Phytate.- B. Calcium Binding by Dietary Fiber.- C. Calcium Absorption from the Colon.- D. Fiber-Rich Diets and Bone Disease in At-Risk Groups.- III. Dietary Fiber and Zinc Status.- IV. Dietary Fiber and Iron Absorption.- V. Conclusions.- References.- 14. Sources and Intakes of Dietary Fiber in Man.- I. Introduction.- A. Problems of Food Intake Assessment.- B. Problems in Dietary Fiber Analysis.- II. Fiber Intakes and Sources.- A. United Kingdom.- B. Europe.- C. Africa.- D. India.- E. United States.- III. Long-Term Trends in Fiber Intake.- A. United Kingdom..- B. United States.- IV. Effects of Social Class.- V. Seasonal Variation.- VI. Individual Variation.- A. Sex.- B. Age.- C. Other Factors.- VII. Conclusions.- References.