Introduction: Soluble fibres are thought to lower blood cholesterol concentrations. A systematic review of the effect of pectin, a soluble fibre, on cholesterol concentrations was undertaken.
Methods: EMBASE, PubMed and Cochrane CENTRAL were searched in December 2013. Randomised controlled trials lasting at least two weeks investigating increased consumption of pectin added to foods or as a supplement compared to a suitable control group and reporting at least total cholesterol concentrations in non-acutely ill subjects were included. Studies testing mixtures of fibres or whole foods were excluded because their effects could not be attributed to pectin. Study quality was assessed using the Risk of Bias criteria; high quality studies were double-blind and placebo-controlled. Meta-analysis was conducted using the generic inverse variance method.
Results: Of the 115 articles retrieved, only seven met all inclusion criteria. These tested intakes of pectin between 9 and 36g/day. The number of participants ranged from six to 66 and most studies were conducted in hypercholesterolaemic people. There was a mean reduction in blood total cholesterol concentration of 0.36 mmol/L (95% CI: -0.52 to -0.19 mmol/L, p<0001) and moderate heterogeneity (I2=45%) across all studies. Similar magnitudes of effect were seen in the four high quality studies and in the one, low quality, study conducted with normocholesterolaemic subjects.
Conclusion: Daily consumption of at least 9 g pectin/day (a large amount compared to current average total fibre intakes) may reduce blood total cholesterol concentrations. Further studies are needed to confirm this effect, especially in normocholesterolaemic populations.
Funding source: none