Dietary fiber: nutritional lessons for macronutrient substitutes.

The wide array of low-fat foods containing soluble fibers have the potential for helping in weight loss or weight control. Consumption of soluble fibers in sufficient quantities has been shown to lower serum lipid concentrations and to improve glycemic response. Some individuals could, eventually, consume a significant portion of their soluble dietary fiber from processed foods containing soluble-fiber fat substitutes. Changes in dietary fiber and starch sources increase the amount of fermentable material reaching the colon. Short-chain fatty acids thus produced are used as an energy source by colonocytes and may inhibit hepatic cholesterol synthesis. However, colonic fermentation can also result in flatulence or diarrhea. In addition, some diets high in soluble fiber have been shown to change intestinal cell morphology in rats. The possible benefits from consumption of a diet high in soluble fiber fat substitutes in serum lipid reduction, glycemic response improvement, and/or weight reduction as well as potential problems in flatulence, mineral absorption, and colonic cell hyperproliferation should be investigated.