Efforts to lower cholesterol through dietary manipulations have had only modest effects. In an attempt to increase the efficacy of diet in the prevention of cardiovascular disease, the Adult Treatment Panel of the National Cholesterol Education Program has recommended adding plant sterols and viscous fibers to the diet. Soy proteins and nuts may have additional health benefits. Jenkins and colleagues examined the cholesterol-lowering potential of a diet low in saturated-fat that included these ingredients.
Forty-six healthy adults with hyperlipidemia completed the four-week study. All participants followed their own diet that was low in saturated fat for one month before the start of the study. They were then randomized into one of the following groups: a very-low-saturated-fat diet without a statin; the same diet with a statin; or a similar diet with added viscous fibers, plant sterols, soy foods, and almonds. Weight, blood pressure, and menu checklists were reviewed at regular intervals. Patients reported their satiety levels on a weekly basis.
All diets were vegetarian, and the intervention diet containing soy foods, viscous fiber, plant sterols, and almonds also included eggs and butter to balance the saturated fat and dietary cholesterol content of the control (non-statin) diet.
Compliance with the prescribed diets was at least 93 percent in all three groups, and all participants reported adequate satiety. At baseline, all three groups had similar blood measurements, including low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and C-reactive protein levels. After four weeks, the control group lowered their LDL-C by 8 percent, increased the LDL-C to HDL-C ratio by 3 percent, and lowered the C-reactive protein level by 10 percent.
The group receiving a statin lowered their LDL-C by 30.9 percent, decreased the LDL-C to HDL-C ratio by 28.4 percent, and lowered the C-reactive protein level by 33.3 percent. The intervention-diet group lowered their LDL-C by 28.6 percent, decreased the LDL-C to HDL-C ratio by 23.5 percent, and lowered the C-reactive protein level by 28.2 percent. The reductions in blood lipid levels in the statin and dietary intervention groups were significantly greater than were the changes in the control group for total cholesterol, LDL-C, apolipoprotein B, and the ratios of total cholesterol to HDL-C, LDL-C to HDL-C, and apolipoprotein B to apolipoprotein A1, with no significant differences between the statin group and the intervention diet group.
Similarly, C-reactive protein levels were significantly lower in both the intervention-diet group and the statin group than in the control group, with no differences between the intervention-diet group and the statin group. The authors conclude that diet alone, if selecting for foods with cholesterol-lowering properties, can lower cholesterol as well as statins.