The two- to fourfold higher risk of cardiovascular disease in diabetes mellitus is more strongly predicted by the postprandial than by the fasting blood glucose and lipids. We aimed to investigate the impact of postprandial changes in serum lipoprotein fractions on lipid peroxidation in type I diabetes mellitus (T1DM).This was a prospective observational study.The study was performed at Antwerp University Hospital, Belgium.Twenty-three well-controlled T1DM patients were included.Patients received a standard breakfast and lunch (50% energy as fat). Blood was sampled at fasting (F), after the post-breakfast hyperglycemic peak (BP), just before lunch (B), after the post-lunch hyperglycemic peak (LP), after the post-lunch dale (LD) and 5 h after lunch (L) for the measurement of serum lipids, lipoprotein subfraction composition, alpha-tocopherol and lipid peroxidation in vivo and in vitro.Serum triacylglycerols (Tgs) increased (from 1.03+/-0.40 at F to 1.60+/-0.87 mmol/l at LP, P=0.001), but cholesterol decreased by 12% in parallel with alpha-tocopherol (from 4.43+/-0.76 at F to 4.12+/-0.82 micromol/mmol total lipid at B, P=0.006). Although plasma malondialdehyde increased from 1.02+/-0.36 at F to 1.14+/-0.40 micromol/L at LP, P=0.03, copper-induced in vitro peroxidation decreased in the low-density lipoprotein and high-density lipoprotein fractions.In well-controlled T1DM patients moderate postprandial increases in serum Tgs are accompanied by a relative deficiency in alpha-tocopherol. Lipid peroxidation in vivo increases but cannot be ascribed to changes in the susceptibility of lipoproteins to copper-induced in vitro peroxidation.
