Clinical trials of adults that reported an increased and measurable consumption of dietary fibre and had a duration of at least two weeks were eligible for inclusion. The primary outcome measures were percentage changes in CRP between intervention and control groups or baseline to end comparison. Participants with diabetes or with coronary heart disease were excluded.
The included study designs varied (crossover, parallel and sequential) and duration ranged from three weeks to 24 months. Participants' mean age ranged from 24 to 40 years old. Body mass index (BMI) ranged from 26 to 35. Intervention and comparison diets varied.
Interventions varied and sometimes included dietary changes other than increased fibre intake, such as Mediterranean, high- or low-fat diets or portfolio diets; comparison diets also varied.
About half of the studies were in healthy and/or overweight or obese patients; other studies were in patients with metabolic syndrome, high triglyceride concentrations, hyperlipidaemia and hypertension. About two thirds of patients were female.
Studies were selected by two reviewers.