Baumgartner Sabine, Mensink Ronald P, Konings Maurice, Schött Hans-F, Friedrichs Silvia, Husche Constanze, Lütjohann Dieter, Plat Jogchum
Department of Human Biology, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands.
Institute of Clinical Chemistry and Clinical Pharmacology, University of Bonn, Bonn, Germany.
Steroids. 2015 Jul;99(Pt B):281-6. doi: 10.1016/j.steroids.2015.01.017. Epub 2015 Feb 2.
Epidemiological studies have reported inconsistent results on the relationship between increased plant sterol concentrations with cardiovascular risk, which might be related to the formation of oxyphytosterols (plant sterol oxidation products) from plant sterols. However, determinants of oxyphytosterol formation and metabolism are largely unknown. It is known, however, that serum plant sterol concentrations increase after daily consumption of plant sterol enriched products, while concentrations decrease after plant stanol consumption. Still, we have earlier reported that fasting oxyphytosterol concentrations did not increase after consuming a plant sterol- or a plant stanol enriched margarine (3.0g/d of plant sterols or stanols) for 4weeks. Since humans are in a non-fasting state for most part of the day, we have now investigated effects on oxyphytosterol concentrations during the postprandial state. For this, subjects consumed a shake (50g of fat, 12g of protein, 67g of carbohydrates), containing no, or 3.0g of plant sterols or plant stanols. Blood samples were taken up to 8h and after 4h subjects received a second shake (without plant sterols or plant stanols). Serum oxyphytosterol concentrations were determined in BHT-enriched EDTA plasma via GC-MS/MS. 7β-OH-campesterol and 7β-OH-sitosterol concentrations were significantly higher after consumption of a mixed meal enriched with plant sterol esters compared to the control and plant stanol ester meal. These increases were seen only after consumption of the second shake, illustrative for a second meal effect. Non-oxidized campesterol and sitosterol concentrations also increased after plant sterol consumption, in parallel with 7β-OH concentrations and again only after the second meal. Apparently, plant sterols and oxyphytosterols follow the same second meal effect as described for dietary cholesterol. However, the question remains whether the increase in oxyphytosterols in the postprandial phase is due to absorption or endogenous formation.
流行病学研究报告了植物甾醇浓度升高与心血管风险之间关系的不一致结果，这可能与植物甾醇形成氧化植物甾醇（植物甾醇氧化产物）有关。然而，氧化植物甾醇形成和代谢的决定因素在很大程度上尚不清楚。然而，已知每日食用富含植物甾醇的产品后血清植物甾醇浓度会升高，而食用植物甾烷醇后浓度会降低。尽管如此，我们之前曾报道，连续4周食用富含植物甾醇或植物甾烷醇的人造黄油（每天3.0克植物甾醇或甾烷醇）后，空腹氧化植物甾醇浓度并未升高。由于人类一天中的大部分时间处于非空腹状态，我们现在研究了餐后状态对氧化植物甾醇浓度的影响。为此，受试者饮用了一份奶昔（50克脂肪、12克蛋白质、67克碳水化合物），其中不含植物甾醇或植物甾烷醇，或者含有3.0克植物甾醇或植物甾烷醇。在长达8小时内采集血样，4小时后受试者饮用第二份奶昔（不含植物甾醇或植物甾烷醇）。通过气相色谱-串联质谱法在富含丁基化羟基甲苯（BHT）的乙二胺四乙酸（EDTA）血浆中测定血清氧化植物甾醇浓度。与对照组和富含植物甾烷醇酯的餐食相比，食用富含植物甾醇酯的混合餐后，7β-羟基胆固醇和7β-羟基谷甾醇浓度显著更高。这些升高仅在饮用第二份奶昔后出现，这说明了第二餐效应。食用植物甾醇后，非氧化胆固醇和谷甾醇浓度也升高，与7β-羟基浓度平行，同样仅在第二餐后出现。显然，植物甾醇和氧化植物甾醇呈现出与膳食胆固醇相同的第二餐效应。然而，餐后氧化植物甾醇的增加是由于吸收还是内源性形成，这个问题仍然存在。
