Riddet Institute, Massey University, Palmerston North, New Zealand.
J Nutr. 2010 Mar;140(3):469-76. doi: 10.3945/jn.109.116293. Epub 2010 Jan 13.
The apparent digestibility of energy-yielding nutrients (carbohydrate, protein, and fat) was predicted in the human upper digestive tract and large bowel separately for 4 diverse diets containing either a single dietary fiber source [wheat bran and pectin (PE) diets] or mixed fiber sources [low-fiber (LF) and high-fiber (HF) diets). A human balance study was undertaken to determine fecal energy and nutrient excretion and a rat model was used to predict human ileal energy and nutrient excretion. Total tract energy digestibility ranged from 92 (HF diet) to 96% (PE diet and LF diet), while at the ileal level it ranged from 79 to 86% for the HF diet to the LF diet. The predicted upper-tract digestion of starch, sugars, and fat was high, with ileal digestibilities exceeding 90% for all diets. Nonstarch polysaccharides were poorly digested in the upper tract for all diets except in the PE diet. The daily quantity of protein excreted at the ileal level was between 2 (HF diet) and 5 (PE diet) times higher than that at the fecal level. The large differences between fecal and ileal nutrient loss highlight that fecal digestibility data alone provide incomplete information on nutrient loss. There is a need to be able to routinely determine the uptake of energy in the upper and lower digestive tracts separately.
分别预测了 4 种不同饮食（含单一膳食纤维来源[麦麸和果胶（PE）饮食]或混合膳食纤维来源[低纤维（LF）和高纤维（HF）饮食]）中人体上消化道和大肠中能量产生营养素（碳水化合物、蛋白质和脂肪）的表观消化率。进行了人体平衡研究以确定粪便能量和营养素排泄，并使用大鼠模型预测人体回肠能量和营养素排泄。全肠道能量消化率范围从 92%（HF 饮食）到 96%（PE 饮食和 LF 饮食），而在回肠水平，HF 饮食到 LF 饮食的能量消化率范围从 79%到 86%。预测的上消化道对淀粉、糖和脂肪的消化率较高，所有饮食的回肠消化率均超过 90%。除了 PE 饮食外，所有饮食在上消化道中非淀粉多糖的消化率都很差。在回肠水平上排泄的蛋白质量每天是粪便水平的 2（HF 饮食）到 5（PE 饮食）倍。粪便和回肠之间营养素损失的巨大差异强调，仅粪便消化率数据不能提供关于营养素损失的完整信息。需要能够常规地分别确定上消化道和下消化道中能量的吸收。
