Maximizing Sterol Effectiveness: Study

A recent study, published in Food & Nutrition Research (January 2009), found that while sterols uniformly worked to lower LDL cholesterol, their power is affected by a number of factors. The study assessed 59 randomized clinical trials published from 1992 to 2006. Maximum results were found where patients:

• Consumed 2.5 grams of sterols or stanol per day. The FDA allows a health claim for products containing as little as .4 grams of plant sterols or .65 grams of plant sterol esters. As such, individuals will often need to take multiple servings of plant sterol products to attain the optimum daily intake. Consumption beyond 2.5 grams did not lead to further reductions ( Foods with Plant Sterols).
• Took plant sterols over the course of the day. Multiple servings were generally found to be more effective than a single serving.

Not surprising, sterols lowered LDL cholesterol by more among individuals with high or very high cholesterol levels, but sterols also proved effective among individuals with optimal to borderline-high LDL cholesterol. The authors also sought to assess the power of sterols across different types of foods. While they generally found that foods with some fat content (greater than 3 grams per serving) and low-fat milks and yogurts may be somewhat better, the evaluation does not appear to control for other elements of diet, lifestyle and medications. More research in the role of plant sterols coupled with a broader approach to therapeutic nutrition for cholesterol management is merited.

Total Dietary Fat: Recommendations of the National Cholesterol Education Program

NCEP Evidence Statement: Unsaturated fatty acids do not raise LDL cholesterol concentrations when substituted for carbohydrates in the diet (Strength of Evidence: A2, B2).

NCEP Recommendation: It is not necesary to restrict total fat intake for the express purpose of reducing LDL cholesterol levels, provided saturated fatty acids are reduced to goal levels (less than 7% of daily calories).

NCEP Evidence Statement: The percent of total fat in the diet, independent of caloric intake, has not been documented to be related to body weight or risk for cancer in the general population. Short-term studies suggest that very high fat intakes (greater than 35% of calories) modify metabolism in ways that could promote obesity (C2). On the other hand, very high carbohydrate intakes (greater than 60% of calories) aggravate some of the lipid and non-lipid risk factors common in the metabolic syndrome (A2. B2, C2).

NCEP Recommendations: Dietary fat recommendations should emphasize reduction in saturated fatty acids. Further, for persons with lipid disorders or the metabolic syndrome, extremes of total fat intake--either high or low--should be avoided. In such persons, total fat intakes should range from 25-35 percent of calories. For some persons with metabolic syndrome, a total fat intake of 30-35 percent may reduce lipid and non-lipid risk factors.

Polyunsaturated Fatty Acids: Recommendations from the National Cholesterol Education Program

NCEP Evidence: Linoleic acid*, a polyunsaturated fatty acid, reduces LDL cholesterol levels when substituted for saturated fatty acids in diets (Strength of Evidence: A1,B1). Polyunsaturated fatty acids can also cause a small reduction in HDL cholesterol when compared with monounsaturated fatty acids (B2). Controlled clinical trials indicate that substitution of polyunsatuarated fatty acids for saturated fatty acids reduces risk for CHD (coronary heart diseases) (A2,B2).

NCEP Recommendations: Polyunsaturated fatty acids are one form of unsaturated fatty acids that can replace saturated fat. Most polyunsaturated fatty acids should be derived from liquid vegetable oils, semi-liquid margarines, and other margarines low in trans fatty acids. Intakes of polyunsaturated fat can range up to 10 percent of total calories. (Note: recommendation for monounsaturated fatty acid is a higher at up to 20 percent of total calories).

*Linoleic acid is a colorless to straw-colored, polyunsaturated fatty acid that is liquid at room temperature and of the omega-6 series. Good sources of linoleic acid from vegetarian sources are sunflower oil, and safflower oil.