Comparison of Low and High Phytosterol Diets With Respect to Cholesterol Metabolism

Phyteaux-II- Regulation of Cholesterol Absorption: Response of LDL to Low and Naturally High Phytosterol Diets

The objective of this study is to compare cholesterol absorption and metabolism after feeding diets naturally low or high in phytosterols. All meals will be prepared in a metabolic kitchen and analyzed for phytosterols. In a randomized crossover design a group of up to 25 healthy subjects will consume diets containing either 100 mg/day or 600 mg/day phytosterols for 4 weeks. At the end of each dietary period percent cholesterol absorption, fecal cholesterol excretion and LDL cholesterol level will be measured. The hypothesis is that LDL cholesterol and cholesterol excretion will be improved on the high phytosterol diet even though macronutrient composition, mineral intake and fiber consumption are similar.

Inclusion Criteria:

• Male or female of any race or ethnicity between 18 to 80 years of age, inclusive;
• Body mass index between 20-35 kg/m2;
• LDL-cholesterol between 100-189 mg/dL based on the average of duplicate screening measures. If the two LDL-C levels differ by more than 30 mg/dL, a third test will be scheduled with all three results averaged;
• Free of chronic disease;
• Willing to eat only the foods that are provided by the Center during the diet periods;
• Willing to consume no more than 1 alcoholic drink per day.
• Willing to abstain from the consumption of alcohol for 48-hours prior to blood draw days;
• Willing to drink no more than 5 cups of caffeine-containing beverages a day.

Exclusion Criteria:

• Age < 18 or > 80 years;
• Based on duplicate screening laboratory values: 1) LDL-C > or = 190 mg/dL; 2) TG > or = 250 mg/dL; 3) blood pressure > or = 160 mm Hg systolic or 95 mm Hg diastolic;
• Documented presence of atherosclerotic disease;
• Diabetes mellitus;
• Renal, hepatic, endocrine, gastrointestinal, hematological or other systemic disease;
• Body mass index > 35;
• For women, pregnancy, breast feeding or postpartum < 6 months;
• For women, peri-menopausal;
• History of drug or alcohol abuse;
• History of depression or mental illness requiring treatment or medication within the last 6 months;
• Multiple food allergies or significant food preferences or restrictions that would interfere with diet adherence;
• Chronic use of over-the-counter medication which would interfere with study endpoints including laxatives and antacids;
• Lifestyle or schedule incompatible with the study protocol;
• Planned continued use of dietary supplements through the study trial;
• Taking any lipid-lowering, or other medications known to affect blood cholesterol