Nutrition and health effects of pectin: A systematic scoping review of human intervention studies

Pectin is composed of a group of complex polysaccharides that are naturally found in various plants and are associated with a range of beneficial health effects. Health outcomes from dietary pectin can vary depending on botanical origin, dietary dose and structure of pectin. The objective of this scoping review is to build a comprehensive overview of the current evidence available on intervention studies conducted in humans and to better understand the possible knowledge gaps in terms of structure-function relationships across the different health-related effects. PubMed and Embase databases were searched using PRISMA-ScR guidelines, yielding 141 references (from the initial 3704), representing 134 intervention studies performed between 1961 and 2022 that met inclusion criteria. Studies were divided into six categories, which included gut health, glycaemic response and appetite, fat metabolism, bioavailability of micronutrients, immune response and other topics. Review of these human intervention studies identified a variety of cohort characteristics and populations (life stage, health status, country), sources/types of pectin (i.e. citrus, sugarbeet, apple, other and non-defined), intervention timeframes (from one single intake to 168 d) and doses (0.1-50 g/d) that were tested for health outcomes in people. Gut health, post-prandial glucose regulation and maintenance of blood cholesterol represented the largest categories of studied outcomes. Further research to strengthen the structure-function relationships for pectin with health properties and associated outcomes is warranted and will benefit from a more precise description of physico-chemical characteristics and molecular compositions, such as degree of esterification, weight, degree of branching, viscosity, gel formation and solubility.