The thesis investigated the hypothesis that differences in the triacylglycerol structure of palmitic acid-rich fats influence lipid metabolism and glucose/insulin homeostasis. A review of the literature and acute test meal and chronic feeding studies were conducted in human subjects. Postprandial changes in plasma lipids, apolipoprotein-B48, glucose, C-peptide, insulin, and glucose dependent insulinotropic polypeptide (GIP) were compared in healthy men (n=25) and women (n=25) following meals providing 50g fat as high-oleic sunflower oil (HOS; control), palm olein (PO), interesterified palm olein (IPO), and lard (0.6, 9.2, 39.1, and 70.5 mol% 16:0 respectively at sn-2) using a randomized crossover design. The sn-2-rich meals elicited lower triacylglycerol concentrations up to 3 h and a lower incremental area under the curve after lard vs. HOS and PO meals. GIP concentrations were lower following the lard and IPO meals vs. HOS and IPO but there were no significant changes in insulin, C-peptide and glucose. The effects of consuming PO (control) vs. IPO vs. HOS on insulin release (measured as increases in C-peptide in response to a test meal) were investigated in healthy Malaysian men (n=10) and women (n=31). Test fats (45g/d) were incorporated into daily meals, and following a 2-week run-in period on the PO diet (30% energy fat; 20% energy PO), participants were randomly allocated to the PO or IPO or HOS diets for three consecutive 6-week periods. No differences between diets in C-peptide secretion, insulin sensitivity or postprandial glucose were observed. The HOS diet lowered total- and LDL-cholesterol, and apolipoprotein-B100 compared with the IPO and PO diets. The work described does not support the assertion that palmitic acid in the sn-2 position has adverse effects on lipid metabolism or glucose/insulin homeostasis compared to that in the sn-1 and sn-3 position. The implications of these findings are discussed in relation to the food industry.
The Acute and Chronic Effects of Palmitic Acid-Rich Triacylglycerols on Cardiovascular Risk
Filippou, A. (Author). 1 Oct 2012
Student thesis: Doctoral Thesis › Doctor of Philosophy