Consumption of Prunes as a Source of Dietary Fiber in Men with Mild Hypercholesterolemia

JOURNAL: American Journal of Clinical Nutrition 53 (1991): 1259-65

AUTHORS: Tinker, L.F., Schneeman, B.O., Davis, P.A., Gallaher, D.G. and Waggoner, C.R.

The study tested the hypothesis that dietary fiber in dried plums can lower plasma cholesterol levels in men with mild to moderate hypercholesterolemia. Dried plums provide approximately 5 to 7 grams of dietary fiber per 100 grams, about 60 percent of which is pectin. Pectin as a type of soluble dietary fiber previously had been shown to lower serum cholesterol in those with hypercholesterolemia. These studies used purified pectin rather than pectin-containing foods. This study tested the ability of pectin-containing whole foods to lower blood cholesterol levels. It also tested the hypothesis that dried plums would increase fecal bile acid excretion as a result of the dietary fiber and that this might help explain the cholesterol-lowering effect. Dietary fiber had been shown to absorb bile acids in-vitro and in-vivo.
This eight-week crossover trial involved 41 free-living adult men with mild hypercholesterolemia (5.2-7.5 mmol/L) serving as his own control. The eight-week period was divided into two experimental diet periods of four weeks each. Subjects were randomly assigned to a fruit juice supplement diet or a dried plum supplement diet. During the dried plum supplement period, subjects supplemented their usual diet with 12 dried plums (100 grams; 6 grams of dietary fiber). During the fruit juice control period, subjects ate their usual diet supplemented with 360 ml of a fruit juice control that was similar to dried plums in simple carbohydrate, but contained negligible dietary fiber. Results indicated that plasma LDL-cholesterol was significantly lower after the dried plum period (3.9 mmol/L) than the fruit juice control period (4.1 mmol/L). Fecal bile acid concentration of lithocholic acid was significantly reduced after the dried plum supplement period compared to the fruit juice control period. Both fecal wet and dry weights were higher after both the dried plum and fruit juice supplement periods. There was no significant difference in total bile acids between experimental periods.