Dose effects of dietary phytosterols on cholesterol metabolism: a controlled feeding study.
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.


METHODS
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.
Racette
Susan B
SB
Washington University School of Medicine, St Louis, MO, and the Pennington Biomedical Research Center, Baton Rouge, LA 63108, USA. racettes@wustl.edu
Lin
Xiaobo
X
Lefevre
Michael
M
Spearie
Catherine Anderson
CA
Most
Marlene M
MM
Ma
Lina
L
Ostlund
Richard E
RE
D000293:Adolescent; D000328:Adult; D000368:Aged; D001794:Blood Pressure; D015992:Body Mass Index; D002784:Cholesterol / Q000378:metabolism*; D008078:Cholesterol, LDL / Q000097:blood; D018592:Cross-Over Studies; D004032:Diet; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D008875:Middle Aged; D010840:Phytosterols / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D055815:Young Adult
D008078:Cholesterol, LDL; D010840:Phytosterols; D002784:Cholesterol