García-Albiach Raimundo, Pozuelo de Felipe María José, Angulo Santiago, Morosini María-Isabel, Bravo Daniel, Baquero Fernando, del Campo Rosa
Servicio de Microbiología, Hospital Universitario Ramón y Cajal and CIBER en Epidemiología y Salud Pública, Madrid, Spain.
Am J Clin Nutr. 2008 Jan;87(1):91-6. doi: 10.1093/ajcn/87.1.91.
Yogurt has traditionally been considered a probiotic-carrier food with health-promoting effects. Despite the universal assumption of this assertion, several researchers have evaluated the real capability of the yogurt bacteria Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus to survive and proliferate in the human intestine and have found contradictory results.
This double-blind crossover study assessed the qualitative and quantitative effects of fresh and heat-treated yogurt on bacterial intestinal microbiota from healthy subjects.
The subjects were divided into experimental (n=63) and control (n=16) groups. The experimental group consumed fresh and heat-treated yogurt for 15 d according to a crossover design with a washout period of 2 wk. Three different fecal samples per individual were recovered: at baseline, after fresh yogurt intake, and after heat-treated yogurt intake. Qualitative changes in microbiota were studied by denaturing gel gradient electrophoresis (DGGE) with universal and lactic acid bacteria (LAB) 16S-rRNA primers. Quantitative changes in LAB, Clostridium coccoides, Clostridium perfringens, and Bacteroides groups were analyzed by real-time polymerase chain reaction.
A particular DGGE stable band pattern was observed in each sample. No significant qualitative differences were detected in any fecal sample. However, a significantly higher density of LAB and C. perfringens and a significant decrease in the density of Bacteroides was observed after consumption of both types of yogurt. Microbiota density was not significantly different between the fresh and heat-treated yogurt groups, except for LAB, which was significantly greater in the fresh yogurt group.
The main change in human microbiota observed after yogurt consumption was an increase in the density of LAB and C. perfringens to the detriment of Bacteroides. Bacterial changes were not different after the consumption of fresh and heat-treated yogurt.
传统上，酸奶被认为是一种具有促进健康作用的益生菌载体食品。尽管这一观点被广泛认可，但一些研究人员评估了酸奶中的德氏乳杆菌保加利亚亚种和嗜热链球菌在人体肠道内存活和增殖的实际能力，结果相互矛盾。
这项双盲交叉研究评估了新鲜酸奶和热处理酸奶对健康受试者肠道细菌微生物群的定性和定量影响。
将受试者分为实验组（n = 63）和对照组（n = 16）。实验组按照交叉设计，在2周的洗脱期后，食用新鲜酸奶和热处理酸奶各15天。每位受试者收集三份不同的粪便样本：基线时、食用新鲜酸奶后和食用热处理酸奶后。通过使用通用引物和乳酸菌（LAB）16S - rRNA引物的变性梯度凝胶电泳（DGGE）研究微生物群的定性变化。通过实时聚合酶链反应分析LAB、粪球菌属、产气荚膜梭菌和拟杆菌属菌群的定量变化。
在每个样本中观察到特定的DGGE稳定条带模式。在任何粪便样本中均未检测到明显的定性差异。然而，食用两种酸奶后，LAB和产气荚膜梭菌的密度显著升高，拟杆菌的密度显著降低。除LAB外，新鲜酸奶组和热处理酸奶组的微生物群密度无显著差异，新鲜酸奶组的LAB密度显著更高。
食用酸奶后观察到的人体微生物群的主要变化是LAB和产气荚膜梭菌的密度增加，而拟杆菌的密度降低。食用新鲜酸奶和热处理酸奶后细菌变化无差异。
