Agostoni C, Carratù B, Boniglia C, Lammardo A M, Riva E, Sanzini E
Department of Pediatrics, San Paolo Hospital, Milan, Italy.
J Pediatr Gastroenterol Nutr. 2000 Nov;31(5):508-12. doi: 10.1097/00005176-200011000-00011.
Previous short observational studies on the free amino acid (FAA) content of human milk have shown that glutamine and glutamic acid increase in the first 4 to 6 weeks of life.
Changes in human milk content of free amino acids (FAAs) was determined at colostrum, 1 month, and 3 months of lactation in 16 healthy lactating women after delivery of full-term infants. Milk was collected at the end of each feeding (hindmilk) during 24 hours.
Glutamic acid and taurine were the most abundant FAAs at colostrum. Although taurine remained stable throughout lactation, glutamic acid (the prevalent FAA) and glutamine increased approximately 2.5 and 20 times, respectively, with progressing lactation representing more than 50% of total FAA at 3 months. The content of essential FAA was also stable, so the change in total FAA content was almost entirely due to the changes in glutamic acid and glutamine.
Breast-fed infants are supplied with progressively increasing amounts of glutamine and glutamic acid throughout lactation. The increasing intake of glutamic acid and glutamine could benefit breast-fed infants with molecules that are likely to protect the enteral mucosa and act as neurotransmitters and as a source of nitrogen.
先前关于人乳中游离氨基酸（FAA）含量的短期观察性研究表明，谷氨酰胺和谷氨酸在生命的前4至6周会增加。
在16名足月婴儿出生后，对16名健康哺乳期妇女在初乳期、产后1个月和3个月时人乳中游离氨基酸（FAA）含量的变化进行了测定。在24小时内每次喂奶结束时（后奶）收集乳汁。
初乳中谷氨酸和牛磺酸是含量最丰富的游离氨基酸。虽然牛磺酸在整个哺乳期保持稳定，但谷氨酸（最主要的游离氨基酸）和谷氨酰胺分别增加了约2.5倍和20倍，随着哺乳期的推进，在3个月时占总游离氨基酸的比例超过50%。必需游离氨基酸的含量也保持稳定，因此总游离氨基酸含量的变化几乎完全归因于谷氨酸和谷氨酰胺的变化。
在整个哺乳期，母乳喂养的婴儿摄入的谷氨酰胺和谷氨酸量逐渐增加。谷氨酸和谷氨酰胺摄入量的增加可能有益于母乳喂养的婴儿，这些分子可能保护肠黏膜，并作为神经递质和氮源发挥作用。
