(12-11-09) Dose effects of dietary phytosterols on cholesterol metabolism: a controlled feeding study.

Racette SB, Lin X, Lefevre M, Spearie CA, Most MM, Ma L, Ostlund RE Jr.

Washington University School of Medicine, St Louis, MO, and the Pennington Biomedical Research Center, Baton Rouge, LA.


BACKGROUND: Phytosterol supplementation of 2 g/d is recommended by the National Cholesterol Education Program to reduce LDL
cholesterol. However, the effects of different intakes of phytosterol on
cholesterol metabolism are uncertain. OBJECTIVE: We evaluated the effects of 3 phytosterol intakes on whole-body cholesterol metabolism. DESIGN: In this placebo-controlled, crossover feeding trial, 18 adults received a phytosterol-deficient diet (50 mg phytosterols/2000 kcal) plus beverages supplemented with 0, 400, or 2000 mg phytosterols/d for 4 wk each, in random order. All meals were prepared in a metabolic kitchen; breakfast and dinner on weekdays were eaten on site. Primary outcomes were fecal cholesterol excretion and intestinal
cholesterol absorption measured with stable-isotope tracers and serum
lipoprotein concentrations. RESULTS: Phytosterol intakes (diet plus
supplements) averaged 59, 459, and 2059 mg/d during the 3 diet periods.
Relative to the 59-mg diet, the 459- and 2059-mg phytosterol intakes
significantly (P < 0.01) increased total fecal cholesterol excretion (36 +/- 6% and 74 +/- 10%, respectively) and biliary cholesterol excretion (38 +/- 7% and 77 +/- 12%, respectively) and reduced percentage intestinal cholesterol absorption (-10 +/- 1% and -25 +/- 3%, respectively). Serum LDL cholesterol declined significantly only with the highest phytosterol dose (-8.9 +/- 2.3%); a trend was observed with the 459-mg/d dose (-5.0 +/- 2.1%; P = 0.077).
CONCLUSIONS: Dietary phytosterols in moderate and high doses favorably alter whole-body cholesterol metabolism in a dose-dependent manner. A moderate phytosterol intake (459 mg/d) can be obtained in a healthy diet without supplementation. This trial was registered at clinicaltrials.gov as NCT00860054.


Source: Am J Clin Nutr. 2009 Nov 4.

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