Background: Many intervention studies have tested the effect of dietary fibers (DFs) on appetite-related outcomes, with inconsistent results. However, DFs comprise a wide range of compounds with diverse properties, and the specific contribution of these to appetite control is not well characterized. Objective: The influence of specific DF characteristics [i.e., viscosity, gel-forming capacity, fermentability, or molecular weight (MW)] on appetite-related outcomes was assessed in healthy humans. Design: Controlled human intervention trials that tested the effects of well-characterized DFs on appetite ratings or energy intake were identified from a systematic search of literature. Studies were included only if they reported 1) DF name and origin and 2) data on viscosity, gelling properties, fermentability, or MW of the DF materials or DF-containing matrixes. Results: A high proportion of the potentially relevant literature was excluded because of lack of adequate DF characterization. In total, 49 articles that met these criteria were identified, which reported 90 comparisons of various DFs in foods, beverages, or supplements in acute or sustained-exposure trials. In 51 of the 90 comparisons, the DF-containing material of interest was efficacious for ≥1 appetiterelated outcome. Reported differences in material viscosity, MW, or fermentability did not clearly correspond to differences in efficacy, whereas gel-forming DF sources were consistently efficacious (but with very few comparisons). Conclusions: The overall inconsistent relations of DF properties with respect to efficacy may reflect variation in measurement methodology, nature of the DF preparation and matrix, and study designs. Methods of DF characterization, incorporation, and study design are too inconsistent to allow generalized conclusions about the effects of DF properties on appetite and preclude the development of reliable, predictive, structure-function relations. Improved standards for characterization and reporting of DF sources and DF-containing materials are strongly recommended for future studies on the effects of DF on human physiology.
Bibliographical noteFunding Information:
This work was conducted by an expert group of the European branch of the International Life Sciences Institute (ILSI Europe). This publication was co-ordinated by the Eating Behaviour and Energy Balance Task Force. The expert group received funding from ILSI Europe’s Eating Behaviour and Energy Balance Task Force members. Industry members of this task force are listed on the ILSI Europe website at http://ilsi.eu/task-forces/nutrition/eating-behaviour-and-energy-balance/. Experts were not paid for the time spent on this work; however, the nonindustry members within the expert group were offered support for travel and accommodation costs from the Eating Behaviour and Energy Balance Task Force to attend meetings to discuss the manuscript and a small compensatory sum (honorarium) with the option to decline. The opinions expressed herein and the conclusions of this publication are those of the authors and do not necessarily represent the views of ILSI Europe nor those of its member companies. This is a free access article, distributed under terms (http:// www.nutrition.org/publications/guidelines-and-policies/license/) that permit unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
- Appetite regulation
- Dietary fiber properties
- Molecular weight
- Weight management