Scope: Postprandial dysmetabolism plays a major role in the pathogenesis of metabolic disorders such as obesity and the polycystic ovary syndrome (PCOS). The aim is to characterize the circulating lipoprotein particle profiles in response to oral glucose, lipid, and protein challenges. 

Methods and results: 17 women with PCOS, 17 control women, and 19 healthy men selected to have similar age and body mass index are studied. Blood samples are collected following the ingestion of 300 kcal in the form of glucose, lipids, or proteins, and they are submitted to two-dimensional (2D) diffusion-ordered 1 H-NMR spectroscopy. Regardless of macronutrient administered, the number of very low-density (VLDL) particles increases whereas low density-lipoprotein (LDL) decreases. High density-lipoprotein (HDL) particles increase only after lipid ingestion. Obese subjects show an increase in the number of large VLDL particles and a decrease in large LDL particles, with a significant reduction in the average particle size of LDL. Patients with PCOS show a particularly unfavorably smaller LDL particle size response to oral lipid intake, regardless of obesity. 

Conclusions: Oral macronutrient challenges induce immediate class-specific postprandial changes in particle number and size of lipoproteins, with lipids inducing a more pro-atherogenic lipoprotein profile compared to glucose and proteins, particularly in obese subjects and women with PCOS.