Gentilcore Diana, Hausken Trygve, Meyer James H, Chapman Ian M, Horowitz Michael, Jones Karen L
Discipline of Medicine, University of Adelaide, Royal Adelaide Hospital, Adelaide, Australia.
Am J Clin Nutr. 2008 Jan;87(1):156-61. doi: 10.1093/ajcn/87.1.156.
Postprandial hypotension frequently occurs in the elderly. The hypotensive response to a meal is triggered by the interaction of nutrients with the small intestine; information relating to the effects of different macronutrients on blood pressure (BP) is limited and inconsistent.
The objective of the study was to determine the effects of intraduodenal glucose, fat, and protein on BP, heart rate (HR), and superior mesenteric artery (SMA) blood flow in healthy older subjects.
Eight subjects received intraduodenal glucose (64 g), fat (10% oil emulsion), protein (72 g whey), or saline (0.9%) at a rate of 2.7 mL/min for 90 min, followed by intraduodenal saline for 30 min. BP, HR, and SMA blood flow were measured.
The falls in systolic BP during infusions of glucose, fat, and protein did not differ significantly (P=0.97); however, the fall occurred significantly earlier during the glucose infusion; (18+/-3.0 min) than during the fat (46+/-11.0 min; P=0.02) and protein 33+/-7 min; P=0.04) infusions. The increases in HR during glucose, fat, and protein infusions (P<0.0001 for all) did not differ significantly. SMA blood flow increased significantly after all infusions (P<0.001 for all), but the increase was significantly (P<0.05) lower after protein than after the other infusions.
Intraduodenal glucose, fat, and protein decrease systolic BP in healthy older subjects, but the onset of the hypotensive response is earlier after glucose, and the effect of protein on SMA blood flow is less than that of the other nutrients.
餐后低血压在老年人中经常发生。对一餐的降压反应是由营养素与小肠的相互作用触发的；关于不同宏量营养素对血压（BP）影响的信息有限且不一致。
本研究的目的是确定十二指肠内输注葡萄糖、脂肪和蛋白质对健康老年受试者的血压、心率（HR）和肠系膜上动脉（SMA）血流的影响。
八名受试者以2.7 mL/分钟的速度接受十二指肠内葡萄糖（64 g）、脂肪（10%油乳剂）、蛋白质（72 g乳清蛋白）或生理盐水（0.9%）输注90分钟，随后十二指肠内输注生理盐水30分钟。测量血压、心率和肠系膜上动脉血流。
输注葡萄糖、脂肪和蛋白质期间收缩压的下降没有显著差异（P = 0.97）；然而，葡萄糖输注期间下降发生得明显更早（18±3.0分钟），比脂肪输注期间（46±11.0分钟；P = 0.02）和蛋白质输注期间（33±7分钟；P = 0.04）更早。葡萄糖、脂肪和蛋白质输注期间心率的增加（所有P<0.0001）没有显著差异。所有输注后肠系膜上动脉血流均显著增加（所有P<0.001），但蛋白质输注后增加幅度显著低于其他输注后（P<0.05）。
十二指肠内输注葡萄糖、脂肪和蛋白质可降低健康老年受试者的收缩压，但葡萄糖输注后降压反应的发作更早，蛋白质对肠系膜上动脉血流的影响小于其他营养素。
