Volek Jeff S, Judelson Daniel A, Silvestre Ricardo, Yamamoto Linda M, Spiering Barry A, Hatfield Disa L, Vingren Jakob L, Quann Erin E, Anderson Jeffrey M, Maresh Carl M, Kraemer William J
Human Performance Laboratory, Department of Kinesiology, University of Connecticut, Storrs, CT, USA.
Am J Cardiol. 2008 Nov 15;102(10):1413-7. doi: 10.1016/j.amjcard.2008.07.022. Epub 2008 Sep 11.
Because carnitine has been shown to decrease oxidative stress and improve endothelial cell functioning, we examined the effects of carnitine supplementation on postprandial flow-mediated dilation (FMD) and circulating biomarkers of inflammation and oxidative stress after a high-fat meal. A randomized, double-blind, placebo-controlled, crossover study design was used. Thirty men and women (age 30 +/- 8 year, body mass 72.9 +/- 17.1 kg, body fat 13.0 +/- 6.4%) participated in 2 vascular testing days, each preceded by 3 weeks of supplementation with either 2 g/day of L-Carnitine (L-Carnitine L-Tartrate) or placebo with a 3- to 5-week washout period between trials. Brachial artery FMD in response to 5 minutes of upper arm occlusion and circulating markers of oxidative stress and inflammation were measured in the fasting state and after a standardized high-fat meal. After 3 weeks of supplementation, peak FMD in the fasting state was similar between the carnitine and placebo trials, averaging 6.6%. Peak FMD during the postprandial period decreased to 5.8% at 1.5 hours during placebo and increased to 7.7% during the carnitine trial (n = 30: p = 0.043 for supplement by time interaction effect). This improvement in postprandial vascular function was most dramatic in subjects who showed a decrease in peak FMD in response to the meal (n = 15: p = 0.003 for supplement by time interaction effect). There was a significant increase in postprandial lipemia and plasma interleukin-6 but no effect of supplementation. There were no significant postprandial changes or supplement effects for plasma tumor necrosis factor-alpha and malondialdehyde. In conclusion, consistent with other work showing a beneficial effect of carnitine on vascular function, these findings indicate that carnitine supplementation in healthy individuals improves postprandial FMD after a high-fat meal.
由于已证明肉碱可降低氧化应激并改善内皮细胞功能，我们研究了补充肉碱对高脂餐后餐后血流介导的血管舒张（FMD）以及炎症和氧化应激的循环生物标志物的影响。采用了随机、双盲、安慰剂对照、交叉研究设计。30名男性和女性（年龄30±8岁，体重72.9±17.1 kg，体脂13.0±6.4%）参加了2个血管测试日，每个测试日前有3周补充2 g/天的L-肉碱（L-肉碱酒石酸盐）或安慰剂，试验之间有3至5周的洗脱期。在禁食状态和标准化高脂餐后，测量肱动脉对5分钟上臂闭塞的反应性FMD以及氧化应激和炎症的循环标志物。补充3周后，肉碱试验和安慰剂试验在禁食状态下的FMD峰值相似，平均为6.6%。安慰剂组餐后1.5小时FMD峰值降至5.8%，而肉碱试验组则升至7.7%（n = 30：补充剂与时间交互作用效应的p = 0.043）。在对餐食反应FMD峰值降低的受试者中，餐后血管功能的这种改善最为显著（n = 15：补充剂与时间交互作用效应的p = 0.003）。餐后血脂和血浆白细胞介素-6显著增加，但补充剂无影响。血浆肿瘤坏死因子-α和丙二醛在餐后无显著变化或补充剂效应。总之，与其他显示肉碱对血管功能有益作用的研究一致，这些发现表明，健康个体补充肉碱可改善高脂餐后的餐后FMD。
