Acute Effects of Dietary Fats and Carbohydrate in Subjects With Metabolic Syndrome

There is increasing evidence suggests that elevated levels of postprandial triacylglycerol (TAG)-rich lipoproteins may promote the development of cardiovascular diseases (CVD). A prolonged and elevated postprandial lipemia is associated with increased risk of CVD by a variety of mechanisms such as insulin resistance, inflammation, endothelial dysfunction and oxidative stress. However, current evidence on the acute effects of type of fats on postprandial insulinaemia, gastrointestinal peptide secretion, inflammatory response, as well as satiation are limited and inconsistent, in particular in metabolic syndrome population in Asian. Hence, this study aimed to investigate the postprandial effects of high fat meals enriched with i) palm olein, ii) high oleic sunflower oil, and iii) high linoleic sunflower oil, compared with a low fat/high carbohydrate meal, in 30 subjects with metabolic syndrome.

A randomized, double-blind, crossover design study was conducted to test the acute effects of high fat meals enriched with (1) saturated fatty acids (SFA); (2) monounsaturated fatty acids (MUFA); (3) polyunsaturated fatty acids (PUFA) vs. (4) a low fat/high carbohydrate (CARB) meal on postprandial insulinaemic, lipaemic and inflammatory responses, as well as gastrointestinal peptide secretion and satiation on 30 metabolic syndrome subjects (15 men and 15 women). Primary outcome of this study is postprandial changes of C-peptide. Other measured outcomes including insulin and glucose responses, lipids, cytokines and gastrointestinal peptides. Subjective appetite measurements were taken as exploratory outcomes using visual analogue scales.

Subjects were asked to participate in four postprandial challenges, separated by at least one week. On the day preceding the postprandial intervention, subjects were provided a low fat meal (\< 10 g) to consume as their evening meal. They were required to fast over night after 10 pm and arrive at the research unit at 7:30 am - 9:00 am the following morning. Fasting blood samples were collected and subjects were instructed to consume the allocated test meal within 10 minutes. Further venous blood will be collected at regular intervals for up to 6 hours postprandially. During the 6 hours of the experimental study, the subjects were refrained from the consumption of any food or drink except plain water which they will be asked to consume at regular intervals (up to 750 mL over the 6 hours).

Eligibility Criteria:
Inclusion Criteria:

* Age 20 - 60
* Elevated TAG with at least 1.7 mmol/L
* Low HDL cholesterol (\< 1.04 mmol/L for men, 1.3 mmol/L for women)
* Elevated blood pressure (systolic at least 130, diastolic at least 85 mmHg)
* Increased waist circumference (at least 90cm for men, 80cm for women)
* Fasting plasma glucose between 5.6 and 7.0 mmol/L

Exclusion Criteria:

* Underweight
* Current use of antihypertensive or lipid lowering medication
* Alcohol intake exceeding a moderate intake (\> 28 units per week)
* Medical history of myocardial infarction, angina, thrombosis, stroke, cancer or diabetes
* Pregnancy or breast-feeding
* Smoker