Cunnane S C, Francescutti V, Brenna J T, Crawford M A
Department of Nutritional Sciences, University of Toronto, Canada.
Lipids. 2000 Jan;35(1):105-11. doi: 10.1007/s11745-000-0501-6.
Docosahexaenoate (DHA) has been increasingly recognized as an important fatty acid for neural and visual development during the first 6 mon of life. One important point of controversy that remains is the degree to which adequate levels of DHA can be acquired from endogenous synthesis in infants vs. what should be provided as dietary DHA. We have approached this problem by a retrospective analysis of published body composition data to estimate the actual accumulation of DHA in the human infant brain, liver, adipose tissue, remaining lean tissue, and whole body. Estimating whether infants can synthesize sufficient DHA required comparison to and extrapolation from animal data. Over the first 6 mon of life, DHA accumulates at about 10 mg/d in the whole body of breast-fed infants, with 48% of that amount appearing in the brain. To achieve that rate of accumulation, breast-fed infants need to consume a minimum of 20 mg DHA/d. Virtually all breast milk provides a DHA intake of at least 60 mg/d. Despite a store of about 1,050 mg of DHA in body fat at term birth and an intake of about 390 mg/d alpha-linolenate (alpha-LnA), the brain of formula-fed infants not consuming DHA accumulates half the DHA of the brain of breast-fed infants while the rest of the body actually loses DHA over the first 6 mon of life. No experimental data indicate that formula-fed infants not consuming DHA are able to convert the necessary 5.2% of alpha-LnA intake to DHA to match the DHA accumulation of breast-fed infants. We conclude that dietary DHA should likely be provided during at least the first 6 mon of life.
二十二碳六烯酸(DHA)已日益被认为是生命最初6个月中对神经和视觉发育至关重要的脂肪酸。一个仍存在争议的重要问题是,婴儿通过内源性合成能够获取足够水平DHA的程度,与应作为膳食DHA提供的量相比如何。我们通过对已发表的身体成分数据进行回顾性分析来解决这个问题,以估计DHA在人类婴儿大脑、肝脏、脂肪组织、其余瘦组织和全身的实际积累情况。估计婴儿是否能够合成足够的DHA需要与动物数据进行比较并外推。在生命的最初6个月中,母乳喂养婴儿全身的DHA积累量约为每天10毫克,其中48%出现在大脑中。为了达到这个积累速度,母乳喂养婴儿每天至少需要摄入20毫克DHA。几乎所有母乳提供的DHA摄入量至少为每天60毫克。尽管足月出生时体内脂肪中储存了约1050毫克DHA,且每天摄入约390毫克α-亚麻酸(α-LnA),但未摄入DHA的配方奶喂养婴儿的大脑积累的DHA量仅为母乳喂养婴儿大脑的一半,而在生命的最初6个月中,身体其他部位实际上会损失DHA。没有实验数据表明未摄入DHA的配方奶喂养婴儿能够将必需的5.2%的α-LnA摄入量转化为DHA,以匹配母乳喂养婴儿的DHA积累量。我们得出结论,至少在生命的最初6个月期间可能应提供膳食DHA。