a Department of Target Organ Toxicology , Organisation for Applied Scientific Research (TNO) , Utrechtseweg 48, 3700 AJ, Zeist: The Netherlands.
b Department of Nutritional Physiology , Organisation for Applied Scientific Research (TNO) , Utrechtseweg 48, 3700 AJ, Zeist: The Netherlands ;
Nutr Neurosci. 2000;3(5):345-55. doi: 10.1080/1028415X.2000.11747332.
A deficient brain serotonin function has been demonstrated in psychiatric disorders and increases in brain serotonin ameliorate emotional and behavioural abnormalities found in depression. The uptake of the serotonin precursor tryptophan into the brain is dependent on nutrients that influence the cerebral availability of tryptophan via a change in the ratio of plasma tryptophan to the sum of the other large neutral amino acids (Trp/LNAA). In the present study, we investigated the time- and dose dependent effects of α-lactalbumin enriched whey protein with a high tryptophan content in combination with two doses of glucose on plasma Trp/LNAA. Twelve healthy subjects participated in a double-blind cross-over study and ingested 200 ml orange juice added with glucose alone or mixed with either 5,10, and 20 g α-lactalbumin or 20 g α-lactalbumin hydrolysate. One half of the subjects received the orange juice with 25 g glucose, whereas the other half of the subjects received the juice with 50 g glucose. Results revealed a relationship between α-lactalbumin dosage and increases in plasma Trp/LNAA [P< 0.001]. Different doses interacted with time-dependent changes in plasma Trp/LNAA [P < 0.0001] such that the most prolonged increase was found with 20 g α-lactalbumin [P < 0.0001]. Changes in plasma Trp/LNAA were not affected by glucose dose. Since increases in plasma Trp/LNAA are indicative of increased serotonin concentrations in the brain, this study shows that ingestion of 20 g α-lactalbumin may be a suitable dietary method to investigate the effect of alterations in brain serotonin.
大脑中血清素功能不足已在精神疾病中得到证实，而增加大脑中血清素可以改善抑郁中发现的情绪和行为异常。色氨酸作为血清素的前体进入大脑取决于营养物质，这些营养物质通过改变血浆色氨酸与其他大中性氨基酸（Trp/LNAA）总和的比值来影响大脑中色氨酸的可用性。在本研究中，我们研究了富含色氨酸的α-乳白蛋白强化乳清蛋白与两种剂量的葡萄糖联合使用对血浆色氨酸/LNAA 的时间和剂量依赖性影响。12 名健康受试者参加了一项双盲交叉研究，摄入 200 毫升添加葡萄糖的橙汁，或与 5、10 和 20 gα-乳白蛋白或 20 gα-乳白蛋白水解物混合。一半受试者接受添加 25 g 葡萄糖的橙汁，而另一半受试者接受添加 50 g 葡萄糖的橙汁。结果显示，α-乳白蛋白剂量与血浆色氨酸/LNAA 的增加之间存在关系[P<0.001]。不同剂量与血浆色氨酸/LNAA 的时间依赖性变化相互作用[P<0.0001]，其中发现 20 gα-乳白蛋白的增加最持久[P<0.0001]。葡萄糖剂量不影响血浆色氨酸/LNAA 的变化。由于血浆色氨酸/LNAA 的增加表明大脑中血清素浓度的增加，因此本研究表明，摄入 20 gα-乳白蛋白可能是一种合适的饮食方法来研究大脑中血清素变化的影响。
