EFFECTS OF QUALITY OF ENERGY INTAKE ON LBW INFANTS

美国儿科学会营养委员会 建议对LBW进行营养支持的一个合乎逻辑的目标 婴儿要达到出生后的生长发育，接近于 妊娠后年龄相同的正常胎儿。到目前为止，尝试 为了在LBW婴儿中实现足够的追赶增长， 出院时，在婴儿的体重和拥有相同的 与受孕后年龄相当的胎儿的身体成分 都失败了。我们之前的研究表明，这是因为 相对较高的蛋白质摄入量没有得到充分利用 除非伴随着能量摄入导致过量 脂肪沉积。因此，我们建议评估一项战略，以 促进瘦体重的增加，而不是过量的脂肪 吸积作用。具体地说，我们将测试假设一个高- 碳水化合物饮食相对于等热量的高脂肪饮食将 提高蛋白质利用率，但可能会对 心肺功能。为了检验这一普遍假设，我们 将系统地研究高密度的不同效应 碳水化合物和高脂肪能量摄入体重增加，氮 色氨酸与大浓度中性物质的保留率 氨基酸、睡眠状态、底物利用、能量消耗 以及肠内喂养、生长中的低体重儿的心肺功能 婴儿(出生体重，750-1600克)。所有婴儿都将获得 蛋白质摄入量为4.0g/kg.d；伴随的能量摄入量将为 120千卡/千克·d(非蛋白质能量65%碳水化合物和35% 脂肪、35%碳水化合物和65%脂肪或50%碳水化合物和50%脂肪) 或150千卡/千克(非蛋白质能量65%碳水化合物和35%脂肪 或35%碳水化合物和65%脂肪)。问题是肥胖和肥胖是否 碳水化合物是等量的能量来源不仅重要 用于LBW婴儿的营养管理，但也可能 与他们的神经行为发育有关。

The Committee on Nutrition of the American Academy of Pediatrics suggests that a logical goal for nutritional support of the LBW infant is to achieve postnatal growth approximating that of a normal fetus of the same post-conceptional age. To date, attempts to achieve sufficient catch-up growth in the LBW infant to result, at discharge, in the infant's weighing the same and having the same body composition as a fetus of comparable post-conceptional age have failed. Our previous studies suggest that this is because the relatively high protein intake required is not utilized completely unless accompanied by an energy intake that results in excessive fat deposition. We, therefore, propose to evaluate a strategy for enhancing accretion of lean body mass without excessive fat accretion. Specifically, we will test the hypothesis that a high- carbohydrate diet relative to an isocaloric high-fat diet will enhance protein utilization but may exert undesirable effects on cardiorespiratory function. To test this general hypothesis, we will examine systematically the differential effects of high- carbohydrate and high-fat energy intakes on weight gain, nitrogen retention, ratio of tryptophan to concentrations of large neutral amino acids, sleep state, substrate utilization, energy expenditure and cardiorespiratory functions of enterally fed, growing LBW infants (Birth weight, 750-1600 g). All infants will receive a protein intake of 4.0 g/kg.d; concomitant energy intake will be either 120 kcal/kg.d (non-protein energy 65% carbohydrate and 35% fat, 35% carbohydrate and 65% fat or 50% carbohydrate and 50% fat) or 150 kcal/kg.d (non-protein energy 65% carbohydrate and 35% fat or 35% carbohydrate and 65% fat). The question whether fat and carbohydrate are equivalent sources of energy is not only important for the nutritional management of LBW infants but may also be relevant to their neurobehavioral development.