Nutrient Absorption in Lean Versus Obese Individuals

我们最初的研究检测了两种标准饮食(2400千卡/天和3400千卡/天)的肥胖者和瘦肉者的粪便和尿液能量损失。 最初的14名瘦身者和9名肥胖者的初步结果没有显示出大便或尿液能量损失的任何差异。两组的大便卡路里范围都很大，从2%到9%不等。与肥胖的人相比，瘦的人在高卡路里的饮食中吸收更多(大便能量损失更少)。主要肠道系统类型Firimutes和拟杆菌的百分比变化与营养负荷的变化有关。菌丝体百分比随营养负荷的增加而增加，类杆菌数随营养物负荷的增加而减少。此外，在瘦肉个体中，主要种型的这些变化与大便能量损失有关，因此，Firmcutes/Bacteroidetes增加或减少20%与大便能量损失约150千卡/天相关。 在这一前期工作的基础上，我们完成了一项新的研究，以证实和推广上述发现。在这项研究中，我们测量了喂养过多和喂养不足(基于计算的体重维持卡路里的150%和50%)期间的粪便能量损失和肠道微生物区系的变化。在此之后，志愿者被随机接受抗生素口服万古霉素和安慰剂(双盲随机方式)。口服万古霉素在健康人体内不被吸收，会选择性地改变肠道细菌种群。我们发现了营养吸收变化对过度喂养和万古霉素反应的重要差异和以前未报道的差异。我们还发现了肠道微生物区系的重要变化，支持其在营养吸收中的作用。

Our initial study examined stool and urine energy losses in obese versus lean individuals on two standard (2400 kcal/d and 3400 kcal/d each given over 3 days) diets. Preliminary results from an initial 14 lean and 9 obese individuals failed to show any difference in stool or urine energy loss. The range of calories stool was large, varying from 2 to 9 % in both groups. Lean individuals absorbed more (had less stool energy loss) on the higher calorie diet compared to obese individuals. Percent changes in the major gut phylotypes, Firimutes and Bacteroidetes, were associated with changes in nutrient load. Percent of Firmicutes increased with nutrient load while Bacteroidetes decreased. In addition, in lean individuals, these changes in the major phylotypes were associated with stool energy loss, such that a 20% increase or decrease in Firmcutes/Bacteroidetes was associated with approximately 150 kcal/day difference in stool energy loss. Based on this preliminary work, we completed a new study to confirm and extend the above findings. In this study, stool energy loss and changes in gut microbiota were measured during over and underfeeding (150 and 50% based on calculated weight maintaining calories). Following this, volunteers were randomized to receive the antibiotic oral vancomycin versus placebo (in a double blind randomized fashion). Oral vancomycin is not absorbed in healthy individuals and will selectively change the gut bacterial population. We found important and previously unreported differences in nutrient absorption changes in response to overfeeding and vancomycin. We have also found important changes in the gut microbiota that support its role in nutrient absorption.