Unilever R&D, Olivier van Noortlaan 120, 3133 AT Vlaardingen, The Netherlands.
Br J Nutr. 2011 Feb;105(4):611-7. doi: 10.1017/S0007114510004150.
Serotonin synthesis critically depends on plasma levels of tryptophan (TRP). Earlier studies have shown that for mood and cognitive benefits to occur, the ratio between TRP and other large neutral amino acids (LNAA) has to be increased by approximately 40 %. The present study investigated the dose-dependent effects of a TRP-rich hydrolysed protein (egg-protein hydrolysate, EPH) on the plasma TRP:LNAA. Moreover, it was investigated whether EPH could increase TRP:LNAA in the presence of 2 g of milk protein (MP). In a randomised double-blind crossover design, plasma amino acids were measured every 30 min for 3·5 h after ingestion of a drink containing either three different doses of 4, 8 and 12 g EPH containing 270, 560 or 800 mg of TRP, respectively, the combination of 4 g EPH and 2 g MP (74 mg TRP), or 4 g MP (148 mg TRP) in twenty healthy subjects with a mean age of 52 years. All three EPH doses caused significant increases of TRP:LNAA above 40 % at 30, 60 and 90 min after consumption in a dose-dependent manner. Compared with the 4 g EPH, the increase in TRP:LNAA in the 4 g EPH with 2 g MP condition was significantly lower at 60 min (63 v. 44 %, P < 0·001) and did not differ significantly at 90 min (58 v. 53 %, P>0·05). The present study showed that a low dose of 4 g EPH with even the addition of 2 g MP was sufficient to increase the ratio of TRP:LNAA above 40 %. Thus, EPH offers a viable ingredient to increase TRP availability.
5-羟色胺的合成严重依赖于色氨酸（TRP）的血浆水平。早期研究表明，为了产生情绪和认知益处，TRP 与其他大中性氨基酸（LNAA）之间的比例必须增加约 40%。本研究调查了富含 TRP 的水解蛋白（卵蛋白水解物，EPH）对血浆 TRP：LNAA 的剂量依赖性影响。此外，还研究了在摄入 2 克牛奶蛋白（MP）的情况下，EPH 是否可以增加 TRP：LNAA。在一项随机双盲交叉设计中，20 名健康受试者在摄入含有 3 种不同剂量（分别为 4、8 和 12 g，分别含有 270、560 和 800 mg TRP）EPH 的饮料后，每隔 30 分钟测量一次血浆氨基酸，3.5 小时。4 g EPH 和 2 g MP 的组合（74 mg TRP），或 4 g MP（148 mg TRP），所有 3 种 EPH 剂量均在摄入后 30、60 和 90 分钟以剂量依赖性方式引起 TRP：LNAA 显著增加超过 40%。与 4 g EPH 相比，4 g EPH 与 2 g MP 条件下 TRP：LNAA 的增加在 60 分钟时显著降低（63 对 44%，P<0·001），而在 90 分钟时差异无统计学意义（58 对 53%，P>0·05）。本研究表明，即使添加 2 g MP，低剂量 4 g EPH 也足以增加 TRP：LNAA 的比例超过 40%。因此，EPH 提供了一种增加 TRP 可用性的可行成分。
