Background: Elevations of postprandial triacylglycerol-rich plasma lipoproteins and suppressions of HDL-cholesterol concentrations are considered potentially atherogenic. Long-term studies have shown beneficial effects of monounsaturated fatty acids (eg, oleic acid) on fasting lipid and lipoprotein concentrations in humans. A direct stimulatory effect of oleic acid on the secretion of glucagon-like peptide 1 (GLP-1) was shown in animal studies. Objective: We compared the postprandial responses of glucose, insulin, fatty acids, triacylglycerol, gastric inhibitory polypeptide (GIP), and GLP-1 to test meals rich in saturated and monounsaturated fatty acids. Design: Ten young, lean, healthy persons ingested 3 meals: an energy-free soup consumed with 50 g carbohydrate (control meal), the control meal plus 100 g butter, and the control meal plus 80 g olive oil. Triacylglycerol and retinyl palmitate responses were measured in total plasma, in a chylomicron-rich fraction, and in a chylomicron-poor fraction. Results: No significant differences in glucose, insulin, or fatty acid responses to the 2 fat-rich meals were seen. Plasma triacylglycerol responses were highest after the butter meal, with chylomicron triacylglycerol rising 2.5-5-fold. Retinyl palmitate responses were higher and more prolonged after the butter meal than after the control and olive oil meals, whereas both postprandial HDL-cholesterol concentrations and GLP-1 and GIP responses were higher after the olive oil meal than after the butter meal. Conclusions: Olive oil induced lower triacylglycerol concentrations and higher HDL-cholesterol concentrations than butter, without eliciting differences in concentrations of glucose, insulin, or fatty acids. Furthermore, olive oil induced higher concentrations of GLP-1 and GIP than did butter, which may point to a relation between fatty acid composition, incretin responses, and triacylglycerol metabolism in the postprandial phase.
Articles you may be interested inIonization and dissociation dynamics of vinyl bromide probed by femtosecond extreme ultraviolet transient absorption spectroscopy J. Chem. Phys. 140, 064311 (2014); 10.1063/1.4865128 Photodissociation of thioglycolic acid studied by femtosecond time-resolved transient absorption spectroscopyOne-color two-photon mass-analyzed threshold ionization spectroscopy of ethyl bromide through a dissociative intermediate stateThe photodissociation and photoionization of liquid water following two-photon absorption at 266 nm is studied in the spectral range from 213 to 1108 nm with subpicosecond time resolution. Probing in the UV enables the first direct simultaneous observation of the photoproducts e aq Ϫ , H aq , and OH aq . This makes it possible to follow the geminate recombination kinetics between the photoproducts and to determine the relative yields of the dissociation and ionization channels. The concentration of hydrated electrons deduced from the visible and near-infrared transient absorption measurements decays by 40%Ϯ2% within the first 90 ps due to recombination with OH aq and H 3 O ϩ . Analyzing our measurements of the hydrated electron concentration using the independent reaction time approximation results in the relative yields of 82%Ϯ3% and 18%Ϯ3% for recombination with OH aq and with H 3 O ϩ , respectively. This is in excellent agreement with the relative yield of 82%Ϯ10% for recombination with OH aq determined directly from our ultraviolet transient absorption measurements. The contribution of hydrated electrons from direct ionization is insignificant when liquid water is excited below 9.32 eV and the ionization is likely to occur via dissociation and proton transfer. The transient ultraviolet absorption data shows that if ionization exclusively occurs via dissociation, 65% of the produced H͑hot͒ atoms react with the surrounding solvent molecules to produce hydrated electrons. If proton transfer, on the other hand, is the only process responsible for the ionization, our measurements show that the ratio between dissociation and ionization is 55%. Geminate recombination of OH aq and H aq fragments following the photodissociation at 9.32 eV is not observed indicating that the translation energy of at least one of the fragments is sufficient to penetrate the water solvent cage. Finally, we have measured the two-photon absorption spectrum of liquid water from 110 to 160 nm, and the spectrum is in good agreement with our ab initio gas-phase calculations of the two-photon absorption cross sections for the transitions involved.
The ultrafast solvation and recombination dynamics of the hydrated electron generated by two-photon ionization of water at 4.65 eV is studied by transient absorption spectroscopy as a function of temperature in the range from 277 K to 355 K. The part of the spectral blue shift which is observed in the absorption spectrum of the hydrated electron after 1 ps is purely continuous and is accurately described by the well known analytical expression for the temperature dependent absorption spectrum of the ground state hydrated electron. This indicates that thermal relaxation or more likely solvation of the hydrated electron predominantly causes the blue shift. The survival probability of the hydrated electron shows a strong temperature dependence, which is satisfactory explained by the temperature dependent mobility and reaction rates of the species involved in the recombination. This implies that the average initial separation between the hydrated electron and the ionization site of 〈r0〉=1.0±0.1 nm does not depend significantly on the bulk water temperature.
Olive oil induced lower triacylglycerol concentrations and higher HDL-cholesterol concentrations than did butter, without eliciting significant changes in glucose, insulin, or fatty acids. Furthermore, olive oil induced higher concentrations of GLP-1, which may indicate a relation between fatty acid composition, incretin responses, and triacylglycerol metabolism postprandially in patients with type 2 diabetes.
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