Plasma kinetics of chylomicron-like emulsion and lipid transfers to high-density lipoprotein (HDL) in lacto-ovo vegetarian and in omnivorous subjects

Abstract

Previously, it was showed that vegan diet improves the metabolism of triglyceride-rich lipoproteins by increasing the plasma clearance of atherogenic remnants. The aim of the current study was to investigate this metabolism in lacto-ovo vegetarians whose diet is less strict, allowing the ingestion of eggs and milk. Transfer of lipids to HDL, an important step in HDL metabolism, was tested in vitro. Eighteen lacto-ovo vegetarians and 29 omnivorous subjects, all eutrophic and normolipidemic, were intravenously injected with triglyceride-rich emulsions labeled with C-14-cholesterol oleate and H-3-triolein. Fractional clearance rates (FCR, in min(-1)) were calculated from samples collected during 60 min. Lipid transfer to HDL was assayed by incubating plasma samples with a donor nanoemulsion labeled with radioactive lipids. LDL cholesterol was lower in vegetarians than in omnivores (2.1 +/- A 0.8 and 2.7 +/- A 0.7 mmol/L, respectively, p < 0.05), but HDL cholesterol and triglycerides were equal. Cholesteryl ester FCR was greater in vegetarians than in omnivores (0.016 +/- A 0.012, 0.003 +/- A 0.003, p < 0.01), whereas triglyceride FCR was equal. Cholesteryl ester transfer to HDL was lower in vegetarians than in omnivores (2.7 +/- A 0.6, 3.5 +/- A 1.5 %, p < 0.05), but free cholesterol, triglyceride and phospholipid transfers and HDL size were equal. Similarly to vegans, lacto-ovo vegetarian diet increases remnant removal, as indicated by cholesteryl oleate FCR, which may favor atherosclerosis prevention, and has the ability to change lipid transfer to HDL.