Butte N F, Hopkinson J M, Mehta N, Moon J K, Smith E O
US Department of Agriculture, Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA.
Am J Clin Nutr. 1999 Feb;69(2):299-307. doi: 10.1093/ajcn/69.2.299.
Metabolic adjustments occur during pregnancy and lactation to support fetal growth and milk synthesis; however, the effect of body composition and hormonal milieu on these changes is poorly understood.
We hypothesized that energy metabolism changes during pregnancy and lactation to support fetal growth and milk synthesis, and that body composition and hormonal milieu influence these alterations.
We measured energy expenditure, body composition, and hormone, metabolite, and catecholamine concentrations in 76 women (40 lactating, 36 nonlactating) at 37 wk gestation and 3 and 6 mo postpartum. Total energy expenditure (TEE), basal metabolic rate (BMR), sleeping metabolic rate (SMR), and minimal SMR (MSMR) were measured with room calorimetry. Fat-free mass (FFM) and fat mass were estimated with a 4-component model.
TEE, BMR, SMR, and MSMR were 15-26% higher during pregnancy than postpartum after being adjusted for FFM, fat mass, and energy balance. TEE, SMR, and MSMR were higher in lactating than in nonlactating women. Fasting serum insulin, insulin-like growth factor I, fatty acids, and leptin, and 24-h urinary free norepinephrine, epinephrine, and dopamine correlated positively with TEE, BMR, SMR, and MSMR. In nonlactating women, the respiratory quotient decreased over time, carbohydrate oxidation decreased, and fat oxidation increased. Substrate utilization was not influenced by body composition, fasting serum hormones, or 24-h urinary catecholamines.
These results indicate increased energy expenditure and preferential use of carbohydrates during pregnancy and lactation. Elevated respiratory quotient and carbohydrate utilization during pregnancy continue during lactation, consistent with preferential use of glucose by the fetus and mammary gland.
孕期和哺乳期会发生代谢调整以支持胎儿生长和乳汁合成；然而，身体成分和激素环境对这些变化的影响却知之甚少。
我们假设孕期和哺乳期能量代谢发生变化以支持胎儿生长和乳汁合成，且身体成分和激素环境会影响这些改变。
我们测量了76名女性（40名哺乳期、36名非哺乳期）在妊娠37周以及产后3个月和6个月时的能量消耗、身体成分、激素、代谢物和儿茶酚胺浓度。使用房间量热法测量总能量消耗（TEE）、基础代谢率（BMR）、睡眠代谢率（SMR）和最低睡眠代谢率（MSMR）。采用四成分模型估算去脂体重（FFM）和脂肪量。
在校正FFM、脂肪量和能量平衡后，孕期的TEE、BMR、SMR和MSMR比产后高15% - 26%。哺乳期女性的TEE、SMR和MSMR高于非哺乳期女性。空腹血清胰岛素、胰岛素样生长因子I、脂肪酸和瘦素，以及24小时尿游离去甲肾上腺素、肾上腺素和多巴胺与TEE、BMR、SMR和MSMR呈正相关。在非哺乳期女性中，呼吸商随时间下降，碳水化合物氧化减少，脂肪氧化增加。底物利用不受身体成分、空腹血清激素或24小时尿儿茶酚胺的影响。
这些结果表明孕期和哺乳期能量消耗增加且优先利用碳水化合物。孕期升高的呼吸商和碳水化合物利用在哺乳期持续存在，这与胎儿和乳腺优先利用葡萄糖一致。
