Specific Dietary Modifications (Viscous Fiber, Plant Sterols, Soy and Nuts) Significantly Reduce Serum LDL Cholesterol

by | Sep 2, 2011 | 2011, Blood Lipids, Cardiovascular Health, Fruits and Vegetables, Nuts and Seeds, Vegetarianism, Whole Grains

Written by Susan Sweeny Johnson, PhD, Biochem. In a study with 351 patients with high levels of fats in the blood, specific dietary modifications (viscous fiber, plant sterols, soy and nuts) significantly reduced serum LDL cholesterol were recommended. This resulted in a 10% reduced risk for coronary heart disease.  

High serum cholesterol, primarily low-density lipoprotein (LDL) cholesterol, is associated with high coronary heart disease (CHD) risk.(1a) The primary cause of CHD is when cholesterol containing particles like LDL adhere to the walls of the arteries that supply blood to the heart muscle and cause blockages. Prescribed statins, drugs that block the body’s production of cholesterol, have been shown to lower LDL cholesterol by an average 20%. (1b,2)  Due to potential side effects, statin prescription for persons without pre-existing cardiovascular disease (CD) or elevated risk for developing it is controversial.

Diets low in saturated fat and cholesterol, and high in whole grain cereals, fruits and vegetables together with exercise regimens can usually decrease LDL cholesterol without statin intervention. (3-4) Dietary intervention is generally tried before prescription of statins. (5)

The specific dietary components, viscous fibers (6), nuts and soy (7-9) and plant sterols (10), have been shown in short term studies to lower LDL cholesterol to some degree. In this new, long-term study, a basic heart healthy diet was compared to the same diet including the addition of plant sterols, viscous fibers, soy protein and nuts monitored for six months. At the start and end of the trial blood lipids and cholesterol were measured. Since adherence to dietary regimens is a limiting factor in their efficacy, two counseling protocols were assessed, one high intensity with seven clinical advising visits and one lower intensity, with two clinical advising visits. This study included 351 hyperlipidemic subjects between 53 and 59 years old divided randomly into three groups: control diet; control diet with added components and lower intensity counseling; and control diet with added components and higher intensity counseling.  Accepted subjects did not take statins and did not have CD, cancer, high blood pressure or diabetes.

Participants were all counseled to follow a control, low weight-maintaining vegetarian diet including low-fat dairy and whole grain cereals, fruits and vegetables. The two study groups also were prescribed dietary additions per 1000kcal total food intake of 0.94 g of plant sterols as plant sterol enriched margarine; 9.8 g of viscous fibers from oats, barley and psyllium; 22.5 g of soy protein as soy milk, tofu, and textured soy protein; 22.5 g nuts as tree nuts and peanuts as previously described. (11) Adherence to diets was determined via self-administered food diaries and checklists.

The only significant (p<0.001) changes in blood lipids after 24 weeks occurred as a lowering of LDL cholesterol 13.8% for the higher intensity group, 13.1% for the lower intensity group compared to 3% for the control group. In addition, the degree to which LDL cholesterol was lowered in each study group correlated with dietary compliance (p<0.001). These decreases in LDL cholesterol correspond to an approximately 10% decrease in calculated risk for CHD. (12)

The dropout rate in this dietary study was 24% overall with no significant difference between the lower or higher intensive groups or the control group. Also, the adherence to inclusion of the four dietary additions at 24 weeks was 46% and 41% for the high and low intensity groups respectively.  This difference was not significant enough to warrant intensive counseling.

In conclusion, this particular study indicates that both a heart healthy diet and inclusion of specific cholesterol lowering foods (i.e. soy protein, viscous fiber, nuts, and plant sterols) can significantly reduce serum LDL cholesterol.

Coronary heart disease is America’s No. 1 killer, and stroke, also a cardiovascular disease, is the No. 3 killer. (13-16) In 2008, an estimated 82.6 million persons in the United States had CD, (16). Heart disease is the leading cause of premature, permanent disability among American workers.(13) Research has demonstrated that avoiding key risk behaviors and receiving early diagnosis and appropriate treatment can prevent a significant portion of death and disability. (14) America’s progress in reducing the death rate from cardiovascular diseases has slowed; suggesting new strategies are needed to control the nation’s No. 1 killer. (13) Cardiovascular diseases cost Americans more than any other disease — an estimated $450 billion in medical costs and lost productivity in 2010 – and these costs are projected to rise to over $1 trillion a year by 2030. (14)

Source: Jenkins, David JA, et al. “Effect of a dietary portfolio of cholesterol-lowering foods given at 2 levels of intensity of dietary advice on serum lipids in hyperlipidemia: a randomized controlled trial.” Jama 306.8 (2011): 831-839.

© 2011 American Medical Association. All rights reserved.

Posted September 2, 2011.

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