Impact of Consuming Plant Sterols on Endothelial Function and Blood Pressure

This is a 13-wk double-blinded, randomized, crossover study design. Following a 1-wk pre-intervention baseline period, subjects will be randomly assigned to follow a healthy eating pattern diet either contain 2.0 g free plant sterols equivalent of their palmityl esters (Plant Sterol Diet) or do not contain plant sterols (Control Diet) for 4 weeks. After a 4-week dietary 'washout' period, they will consume the alternative diet for 4 weeks. The random assignment will be done with SAS 9.4 software. Body size measurement, dietary assessment, brachial artery FMD and blood pressure measurements, and fasting-state blood collection will be conducted at week 1, 5, 9, and 13, which correspond to before and during the last 1 week of the two 4-week intervention periods.

During study week 1 and weeks 6-9, all subjects will consume their habitual, unrestricted self-chosen diets. During study weeks 2-5 and 10-13, all subject will follow a healthy eating pattern diet, referred to as the "My Healthy Plate" designed by HPB. Each subject's energy requirement will be estimated using sex-specific equations and Recommended Dietary Allowances for healthy Singaporean. One-on-one dietary counselling and written instructions for each subject will be provided by a research dietitian and trained research staff to achieve a healthy eating pattern diet. Compliance with the plant sterols consumption will be promoted by frequent online and in-person contact.

Inclusion criteria

• Ability to give an informed consent;
• Age>35 years old;
• Meet any 3 of the 5 following NCEP-ATP III MetS criteria (waist circumference > 90 cm (male), > 80 cm (female); fasting glucose concentration ≥ 100 mg/dL or on medication; triglyceride ≥ 150 mg/dL or on medication; high density lipoprotein cholesterol (HDL) < 40 mg/dL (male), < 50 mg/dL (female); systolic or diastolic blood pressure > 130/80 mmHg or on medication);
• Weight change < 3kg in the past 3 months;
• No exercising vigorously over the past 3 months;
• No allergy to plant sterols; no acute illness; not smoking;
• No drinking more than 2 alcoholic drinks per day;
• No pregnant, lactating, or planning pregnancy in the next 6 months.

Exclusion criteria

• Unable to give an informed consent;
• Age<35 years old;
• Meet less than 3 of following NCEP-ATP III MetS criteria (waist circumference > 90 cm (male), > 80 cm (female); fasting glucose concentration ≥ 100 mg/dL or on medication; triglyceride ≥ 150 mg/dL or on medication; high density lipoprotein cholesterol (HDL) < 40 mg/dL (male), < 50 mg/dL (female); systolic or diastolic blood pressure > 130/80 mmHg or on medication);
• Weight change > 3kg in the past 3 months;
• Exercise vigorously over the past 3 months;
• Allergy to plant sterols; no acute illness; not smoking;
• Drinking more than 2 alcoholic drinks per day;
• Pregnant, lactate, or plan pregnancy in the next 6 months.