Nutrient Absorption in Lean Versus Obese Individuals

这项研究与圣路易斯华盛顿大学的Jeffrey Gordons博士合作，在两种标准饮食(2400千卡/天和3400千卡/天)下检测了肥胖和瘦人的粪便和尿液能量损失。粪便样本将被送往确定粪便细菌菌群类型，以检查粪便能量损失和肠道菌群之间的联系。 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。 在这项初步工作的基础上，这项研究已被修正，以证实和扩展这些发现。大便能量损失和肠道微生物区系的变化将在喂养过多和喂养不足的情况下进行测量(基于计算的体重维持卡路里的150%和50%)。这项研究还将志愿者随机服用抗生素(阿莫西林和甲硝唑)，这将选择性地改变肠道细菌种群，这样我们就可以建立肠道微生物区系变化和营养获取(通过粪便能量损失衡量)之间的因果联系。我们还将研究肠道微生物区系的变化如何影响葡萄糖耐量和底物氧化。

This 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 In collaboration with Dr. Jeffrey Gordons lab at Washington University in St. Louis, samples of stool will be sent for determination of the fecal bacterial flora phylotypes to examine the association between stool energy loss and enteric flora populations. 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 in this preliminary work, the study has been ammended to confirm and extend these findings. Stool energy loss and changes in gut microbiota will be measured with over and underfeeding (150 and 50% based on calculated weight maintaining calories). This study will also randomize volunteers to antibiotics (amoxicillin and metronidazole) which will selectively change the gut bacterial population so we can establish a causal association between changes in gut microbiota and nutrient harvest (as measured by stool energy loss). We will also investigate how changes in gut microbiota affect glucose tolerance and substrate oxidation.