Plant sterols lower cholesterol

Nutrition Research Newsletter, July, 2005

Type 2 diabetes is associated with metabolic disturbances and is frequently linked with several lipid abnormalities, including hypertriglycerolemia,

elevated VLDL cholesterol and reduced HDL cholesterol. Studies have shown that persons with type 2 diabetes have an increased synthesis and a decreased absorption of cholesterol and as a result, the risk of developing cardiovascular disease (CVD) is 2-fold to 7-fold more than in nondiabetic persons.

Plant sterols, which chemically reduce cholesterol, have been shown to block the absorption of dietary and endogenously derived cholesterol from the gut. The efficacy of plant sterols in diabetics compared with nondiabetics has not been well examined in previous studies. Further investigation is necessary to define dietary strategies that can best normalize the risk of CVD and associated complications in type 2 diabetes. Therefore, a recent study compared the degree of response of plasma lipid concentrations and glycemic control between hypercholesterolemic type 2 diabetic and nondiabetic subjects consuming plant sterols in a controlled dietary setting.

Fifteen nondiabetic subjects and 14 diabetic subjects participated in this double-blind, randomized, crossover, placebo-controlled feeding trial. The diet included 1.8 g/day of either plant sterols (which was added to margarine) or a cornstarch placebo over 21 days. The diets were separated by a 28-day washout period. At baseline and at the end of each dietary phase (day 21 and day 22), fasting blood samples were taken for the measurement of circulating lipid concentrations.

Plant sterol consumption significantly reduced LDL-cholesterol concentrations from baseline in both nondiabetic and diabetic subjects by 15.1% and 26.8%, respectively. The diabetic subjects had significantly lower absolute concentrations of total cholesterol after treatment than did the nondiabetics. However, there was no significant difference in the percentage change from the beginning to the end of the trial. There was also a significant decrease in absolute non-HDL-cholesterol levels after treatment in both groups.

The results showed that overall lipid changes were more favorable in diabetic subjects than in nondiabetic-controls. In general, the findings agree well with those of earlier studies using plant sterols, which showed reductions in total cholesterol and LDL cholesterol in the range of 5% to 13% and 5.6% to 24.4%, respectively. Incorporation of plant sterols into a low saturated-fat and low cholesterol diet for persons at increased risk of CVD mortality could have a positive effect on reducing the mortality rate associated with type 2 diabetes but also on the general health of someone without diabetes.

Vivian W. Y. Lau, Melanie Journoud, and Peter J. H. Jones. Plant Sterols are Efficacious in Lowering Plasma LDL and non-HDL Cholesterol in Hypercholesterolemic Type 2 Diabetic and Nondiabetic Persons. Am J Clin Nutr; 81: 13511358 (June, 2005). [Address reprint requests to P. J. H. Jones, School of Dietetics and Human Nutrition, McGill University, 21,111 Lakeshore Road, Ste-Anne-de-Bellevue, Quebec, Canada, H9X 3V9. E-mail: peter.jones@mcgill.ca]