Wong W W
Department of Pediatrics, Baylor College of Medicine, Texas Children's Hospital, Houston.
J Am Coll Nutr. 1994 Aug;13(4):332-7. doi: 10.1080/07315724.1994.10718418.
Because of the difficulty in obtaining accurate dietary intake information on children and adolescents, the World Health Organization (WHO) has recommended that energy requirements in children and adolescents are best established by estimate of energy expenditure in free-living individuals. To define the energy requirements of healthy female adolescents, we used the doubly labeled water method to estimate the total energy expenditure (TEE) of nine female Caucasian adolescents (mean age +/- SD 13.2 +/- 1.8 years; range 10.3-16 years).
We collected a baseline plasma and saliva sample from each subject after she received by mouth 125 mg of 18O and 100 mg of 2H2O/kg body weight. A 3-hour postdose plasma sample was also collected. Subsequently at home, each subject collected one postdose saliva sample daily for the next 10 days. The 24-hour respiratory quotient (RQ) of each subject was measured by whole-room calorimetry. The 18O and 2H abundances of the plasma and saliva samples were measured by gas-isotope-ratio mass spectrometry. Isotope dilution spaces of 18O (No) and 2H (NH) were calculated from the enrichment levels of these isotopes in the 3-hour postdose plasma sample. The fractional turnover rates of 18O (ko) and 2H (kH) were calculated from the monoexponential decay curves of these isotopes in the saliva samples. The average CO2 production rate (rCO2) over the 10-day period was calculated as rCO2 (mol/day) = 0.4584 x (ko x No-kH x NH). The average TEE was calculated from the rCO2 using the Weir equation.
TEE calculated by the isotope method was 2322 +/- 281 kcal/day (range 1850-2656 kcal/day), which is higher than the levels of energy expenditure (1910-2140 kcal/day) reported by the WHO for healthy female teenagers with a desirable body composition and appropriate level of physical activity.
Our results suggest that the activity factors used by the WHO in the calculation of energy expenditure of female adolescents between 10 and 16 years of age might have been underestimated.
由于难以获取儿童和青少年准确的饮食摄入信息，世界卫生组织（WHO）建议通过估计自由生活个体的能量消耗来确定儿童和青少年的能量需求。为了确定健康女性青少年的能量需求，我们使用双标水法估计了9名白人女性青少年（平均年龄±标准差13.2±1.8岁；范围10.3 - 16岁）的总能量消耗（TEE）。
在每位受试者口服125mg 18O和100mg 2H2O/kg体重后，我们采集了其基线血浆和唾液样本。还采集了给药后3小时的血浆样本。随后，每位受试者在家中在接下来的10天里每天采集一份给药后的唾液样本。通过全室量热法测量每位受试者的24小时呼吸商（RQ）。通过气体同位素比率质谱法测量血浆和唾液样本中18O和2H的丰度。根据给药后3小时血浆样本中这些同位素的富集水平计算18O（No）和2H（NH）的同位素稀释空间。根据唾液样本中这些同位素的单指数衰减曲线计算18O（ko）和2H（kH）的分数转换率。10天期间的平均二氧化碳产生率（rCO2）计算为rCO2（mol/天）= 0.4584×（ko×No - kH×NH）。使用韦尔方程根据rCO2计算平均TEE。
通过同位素法计算的TEE为2322±281千卡/天（范围1850 - 2656千卡/天），高于WHO报告的具有理想身体成分和适当身体活动水平的健康女性青少年的能量消耗水平（1910 - 2140千卡/天）。
我们的结果表明，WHO在计算10至16岁女性青少年能量消耗时使用的活动因子可能被低估了。
