以平衡代谢为基准的不同能量换算系统一致性体内试验研究

A comparative study on differences of various food energy conversion systems in vivo

目的评价不同食物能量换算系统在我国日常膳食能量估算上的一致性。方法:通过人体试食试验测定低纤膳食、普通膳食、低燕麦DF,高燕麦DF、低玉米DF和高玉米DF膳食的食物燃烧能、总粪能、总尿能、产能营养素和DF含量,分析测定的代谢能与不同食物能量换算系统计算的能量值之间的差异。结果:总体上各能量换算系统的能量值之间存在差异,与测定的代谢能相比,阿特氏通用系数系统高估了4%,我国采用的系统低估了3.4%,净代谢能系统低估了6%,改进的代谢能系统和Livesey以总能为基础的经验公式较接近测定的代谢能。结论:膳食纤维是造成各能量系统之间存在差异的重要原因,中国应用的能量换算系统低估了能量值。

Objectives: To evaluate the bias or accuracy of 5 different food energy conversion systems on prediction of energy values with designed Chinese Diets. Methods: 6 diets were designed: a low fiber diet (rice and animal foods); a typical Chinese basal diet (rice, vegetables and animal foods); wheat and oat dietary fiber (DF) product with two doses were added to the basic diet respectively. Duplicate food sample, whole feces and urine of each volunteer were collected and the combustible energy, energy contributing components and DF were determined. Daily intake energy of each diet were calculated by 4 metabolizable energy (ME) food energy conversion systems(MEAtw,MECh,MELiv and MEmod)and net metabolizable energy (NME) system, and the bias of each system were estimated on the base of determined metabolizable energy (ME det). Results: Totally,the relative and absolute difference of energy value between each energy systems and MEdet were significantly different(P<0.5): MEAtw overestimated the metabolizable energy of the diets about 4%, MECh lower estimated 3.4%, and MELiv and MEmod lower estimated the daily intake ME from diets 1% and 0.22% respectively. The relative difference of NME value is about 6% lower than MEdet. The relative and absolute differences of energy value between each energy system and MEdet of each diet group were significantly different (P<0.05), the differences of energy values of high Maize DF group were significantly higher than other groups (P<0.05). Conclusions: Different energy systems may produce differences on energy value, MEmod have the best correlation and consistency among the systems. DF was related with the differences of energy value of each system. Chinese applied system may lower predict the energy values of foods, especially lower evaluated the energy of foods contain rich in fiber.