EFFECTS OF QUALITY OF ENERGY INTAKE ON LBW INFANTS

美国儿科学会营养委员会 提示LBW营养支持的合理目标 婴儿出生后的生长速度接近 相同受孕后年龄的正常胎儿。 迄今为止， 为了在LBW婴儿中实现足够的追赶生长， 出院时，婴儿的体重相同， 与受孕后年龄相当的胎儿的身体组成 失败了我们以前的研究表明，这是因为 所需的相对高的蛋白质摄入量没有被完全利用 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， 促进瘦体重的增加，而不产生过多的脂肪 增积具体来说，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， 提高蛋白质利用率，但可能对 心肺功能 为了验证这个假设，我们 将系统地研究高- 碳水化合物和高脂肪能量摄入对体重增加，氮 保留，色氨酸与大分子中性蛋白浓度的比值 氨基酸，睡眠状态，底物利用，能量消耗 肠内喂养的生长期LBW的心肺功能 婴儿（出生体重，750-1600 g）。 所有婴儿将获得 蛋白质摄入量为4.0 g/kg.d;伴随的能量摄入量将 120 kcal/kg.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 kcal/kg.d（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）。 问题是脂肪和 碳水化合物是能量的等价来源不仅重要 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.