Phytosterols and pectin added to a high-saturated fat diet do not show hypocholesterolemic activity in female guinea pigs

This paper presents the results of a study whose aim was to test the effects of several doses of pectin and phytosterols on the sterol content in plasma, liver and feces of guinea pigs, when added to a high-saturated fat diet. The treatments followed a 3x3 factorial design, with three levels of pectin (0, 3.67 and 6.93%) and three levels of phytosterols (0, 1.37 and 2.45%). Seventy-two female Dunkin Hartley guinea pigs were randomly assigned to the treatment groups (eight animals per group). The duration of the treatment was 4 weeks. No differences were found in plasma cholesterol concentrations, while in liver we saw a reduction in cholesterol concentration after phytosterol feeding. Moreover, we found no pectin effects. Plant sterol concentration increased in plasma and liver after phytosterol ingestion, with the highest concentrations being obtained with the intermediate pectin dose. Our results suggest that a high-saturated diet may impair the cholesterol-lowering properties of plant sterols and pectin.