Department of Applied Nutrition and Food Chemistry, Lund University, Lund, Sweden.
PLoS One. 2013 Nov 13;8(11):e80476. doi: 10.1371/journal.pone.0080476. eCollection 2013.
Obesity is linked to type 2 diabetes and risk factors associated to the metabolic syndrome. Consumption of dietary fibres has been shown to have positive metabolic health effects, such as by increasing satiety, lowering blood glucose and cholesterol levels. These effects may be associated with short-chain fatty acids (SCFAs), particularly propionic and butyric acids, formed by microbial degradation of dietary fibres in colon, and by their capacity to reduce low-grade inflammation.
To investigate whether dietary fibres, giving rise to different SCFAs, would affect metabolic risk markers in low-fat and high-fat diets using a model with conventional rats for 2, 4 and 6 weeks.
Conventional rats were administered low-fat or high-fat diets, for 2, 4 or 6 weeks, supplemented with fermentable dietary fibres, giving rise to different SCFA patterns (pectin - acetic acid; guar gum - propionic acid; or a mixture - butyric acid). At the end of each experimental period, liver fat, cholesterol and triglycerides, serum and caecal SCFAs, plasma cholesterol, and inflammatory cytokines were analysed. The caecal microbiota was analysed after 6 weeks.
Fermentable dietary fibre decreased weight gain, liver fat, cholesterol and triglyceride content, and changed the formation of SCFAs. The high-fat diet primarily reduced formation of SCFAs but, after a longer experimental period, the formation of propionic and acetic acids recovered. The concentration of succinic acid in the rats increased in high-fat diets with time, indicating harmful effect of high-fat consumption. The dietary fibre partly counteracted these harmful effects and reduced inflammation. Furthermore, the number of Bacteroides was higher with guar gum, while noticeably that of Akkermansia was highest with the fibre-free diet.
肥胖与 2 型糖尿病和代谢综合征相关的危险因素有关。膳食纤维的摄入已被证明对代谢健康有积极影响，例如增加饱腹感、降低血糖和胆固醇水平。这些作用可能与短链脂肪酸（SCFAs）有关，特别是丙酸和丁酸，它们是膳食纤维在结肠中被微生物降解形成的，并且具有降低低度炎症的能力。
使用常规大鼠模型，研究在低脂和高脂饮食中，产生不同 SCFA 的膳食纤维是否会影响代谢风险标志物，时间为 2、4 和 6 周。
常规大鼠给予低脂或高脂饮食，2、4 或 6 周，补充可发酵膳食纤维，产生不同的 SCFA 模式（果胶-乙酸；瓜尔胶-丙酸；或混合物-丁酸）。在每个实验期结束时，分析肝脂肪、胆固醇和甘油三酯、血清和盲肠 SCFA、血浆胆固醇和炎症细胞因子。6 周后分析盲肠微生物群。
可发酵膳食纤维可减少体重增加、肝脂肪、胆固醇和甘油三酯含量，并改变 SCFA 的形成。高脂饮食主要减少 SCFA 的形成，但在较长的实验期后，丙酸和乙酸的形成恢复。随着时间的推移，高脂饮食中琥珀酸的浓度增加，表明高脂摄入具有有害作用。膳食纤维部分抵消了这些有害作用并减少了炎症。此外，高脂饮食中使用瓜尔胶时双歧杆菌的数量较高，而纤维含量最低的饮食中阿克曼氏菌的数量明显最高。
