Su H M, Bernardo L, Mirmiran M, Ma X H, Corso T N, Nathanielsz P W, Brenna J T
Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853, USA.
Pediatr Res. 1999 Jan;45(1):87-93. doi: 10.1203/00006450-199901000-00015.
The dietary bioequivalence of alpha-linolenic (LNA) and docosahexaenoic acids (DHA) as substrates for brain and retinal n-3 fatty acid accretion during the brain growth spurt is reported for neonatal baboons who consumed a long-chain-polyunsaturate free commercial human infant formula with a n-6/n-3 ratio of 10:1. Neonates received oral doses of 13C-labeled fatty acids (LNA*) or (DHA*) at 4 wk of age, and at 6 wk brain (occipital cortex), retina, retinal pigment epithelium, liver, erythrocytes, and plasma were analyzed. In the brain, 1.71% of the preformed DHA* dose was detected, whereas 0.23% of the LNA* dose was detected as DHA*, indicating that preformed DHA is 7-fold more effective than LNA-derived DHA as a source for DHA accretion. In LNA*-dosed animals, DHA* was greater than 60% of labeled fatty acids in all tissues except erythrocytes, where docosapentaenoic acid was 55%. Estimates using dietary LNA levels as tracees indicate that brain turnover of DHA is less than 5% per week between weeks 4 and 6 of life. For retina and retinal pigment epithelium, preformed DHA was at levels 12-fold and 15-fold greater than LNA-derived DHA. Liver, plasma, and erythrocytes ratios were 27, 29, and 51, respectively, showing that these pools do not parallel tissue metabolism of a single dose of omega-3 fatty acids. The distributions of labeled fatty acids for LNA*-dosed animals were similar, in the order DHA > DPA > EPA > LNA, except for erythrocytes where docosapentaenoic acid predominated. These are the first direct measurements of the bioequivalence of DHA and LNA in neonatal primate brain and associated tissues.
对于食用了n-6/n-3比例为10:1的长链多不饱和脂肪酸-free商业婴儿配方奶粉的新生狒狒，报道了α-亚麻酸（LNA）和二十二碳六烯酸（DHA）作为大脑生长突增期间大脑和视网膜n-3脂肪酸积累底物的膳食生物等效性。新生狒狒在4周龄时口服13C标记的脂肪酸（LNA*）或（DHA*），并在6周龄时对大脑（枕叶皮质）、视网膜、视网膜色素上皮、肝脏、红细胞和血浆进行分析。在大脑中，检测到预先形成的DHA剂量的1.71%，而检测到LNA剂量的0.23%作为DHA*，这表明预先形成的DHA作为DHA积累的来源比LNA衍生的DHA有效7倍。在给予LNA的动物中，除红细胞中二十二碳五烯酸占55%外，所有组织中DHA均大于标记脂肪酸的60%。使用膳食LNA水平作为示踪剂的估计表明，在生命的第4周和第6周之间，大脑中DHA的周转率每周小于5%。对于视网膜和视网膜色素上皮，预先形成的DHA水平分别比LNA衍生的DHA高12倍和15倍。肝脏、血浆和红细胞的比例分别为27、29和51，表明这些库与单剂量ω-3脂肪酸的组织代谢不平行。给予LNA*的动物中标记脂肪酸的分布相似，顺序为DHA>DPA> EPA>LNA，但红细胞中二十二碳五烯酸占主导地位。这些是对新生灵长类动物大脑及相关组织中DHA和LNA生物等效性的首次直接测量。
