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United States Department of Agriculture

Agricultural Research Service

Title: Phytosterol intake and dietary fat reduction are independent and additive in their ability to reduce plasma LDL cholesterol

Authors
item Chen, Shirley - MEDSTAR RESEARCH INST
item Judd, Joseph - RETIRED-ARS
item Kramer, Matthew
item Meijer, Gert -
item Clevidence, Beverly
item Baer, David

Submitted to: Lipids
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 1, 2008
Publication Date: January 15, 2009
Repository URL: http://www.springerlink.com/content/a61445x4h1w7326w/?p=c80fe662823c4cd48725fc9d9f79ff40&pi=17
Citation: Chen, S.C., Judd, J.T., Kramer, M.H., Meijer, G.W., Clevidence, B.A., Baer, D.J. 2009. Phytosterol intake and dietary fat reduction are independent and additive in their ability to reduce plasma LDL cholesterol. Lipids. 44(3):273-281.

Interpretive Summary: Plant sterols (PS) are naturally occurring substances that lower plasma LDL-cholesterol. However, it is unknown if the composition of the background diet is important for these compounds to work. We conducted a study to determine the effects of changing dietary contents of PS and fat on plasma lipids, lipoproteins, PS, and carotenoids. In a double-blind, randomized controlled crossover study, mildly hypercholesterolemic men (n=13) and postmenopausal women (n=9) participated in four controlled feeding periods of 23 d each. The design consisted of two levels of PS (0 and 3.3 g/d) and two background diets having fat content either typical of the American diet (TAD) or meeting the recommendations of a National Cholesterol Education Program Step I type diet (Step I). Plasma LDL-cholesterol, campesterol, and sitosterol concentrations were 4.7%, 8.5%, and 6.3% lower, respectively, with the Step I diet than with the TAD. PS intake significantly lowered LDL cholesterol by 12.6% and increased campesterol by 94.6% and sitosterol by 34.3%. For plasma concentrations of LDL-cholesterol and sitosterol, the effects of diet and PS were independent. For campesterol, there were significant diet and PS interactions as well as PS and baseline interactions. After consuming PS, the increase in plasma campesterol concentration was greater after the TAD (101%) than after the Step I diet (88%) and was positively associated with the baseline value. The results of this study demonstrate that the effect of PS intake on plasma total cholesterol, LDL-cholesterol, and sitosterol concentrations is independent of and additive to dietary fat reduction. PS intake elevates plasma campesterol concentrations more after a TAD than after a Step I diet and more in subjects having higher initial values. These results are important for the food manufacturing industry, especially companies involved with producing functional foods, and to individuals who are interested in making dietary choices that can decrease risk for disease, as well as health professionals and policy makers who provide recommendations concerning plant sterols.

Technical Abstract: The plasma LDL-cholesterol-lowering effect of plant sterols (PS) appears to be independent of background diet, but definitive proof is lacking. The effect of background diet on plasma concentrations of PS has not been reported. We determined the effects of manipulating dietary contents of PS and fat on plasma lipids, lipoproteins, PS, and carotenoids. Mildly hypercholesterolemic men (n=13) and postmenopausal women (n=9) underwent 4 randomized, crossover, double-blind, controlled feeding periods of 23 d each. The design consisted of 2 levels of PS (0 and 3.3 g/d) and 2 background diets having fat content either typical of the American diet (TAD) or meeting the recommendations of a National Cholesterol Education Program Step I type diet (Step I). Plasma LDL-cholesterol, campesterol, and sitosterol concentrations were 4.7%, 8.5%, and 6.3% lower, respectively (P=0.0016, 0.0022, 0.0044), with the Step I diet than with the TAD. PS intake lowered LDL-cholesterol by 12.6% and increased campesterol by 94.6% and sitosterol by 34.3% (P<0.0001 for all). For plasma concentrations of LDL-cholesterol and sitosterol, the effects of diet and PS were independent. For campesterol, there were significant diet and PS and PS and baseline interactions. After PS intake, the increase in plasma campesterol concentration was greater after the TAD (101%) than after the Step I diet (88%; P=0.0021) and was positively associated with the baseline value. The effect of PS intake on plasma total cholesterol, LDL-cholesterol, and sitosterol concentrations is independent of and additive to dietary fat reduction. PS intake elevates plasma campesterol concentrations more after a TAD than after a Step I diet and more in subjects having higher initial values.

Last Modified: 12/19/2014