(1) Good initial weight loss with moderate late regain, anemia, and multiple nutrient deficits was the common pattern. (2) Massive weight loss, frequent vomiting, dumping syndrome, and women in reproductive age were risk factors for hemoglobin or vitamin deficits, whereas superobesity, diabetes, and use of multiple drugs were associated with EWL result. (3) Most laboratory tests became stable by 2 years and along with BMI correlated with late EWL. (4) Two-year nutritional investigation is especially recommended because of its long-term predictive value.

PURPOSE:The aim of this study was to standardize the methods of sample collection of mucus from the digestive tract and to determine the microbiota in healthy volunteers from Brazil, collecting samples from the mouth, esophagus, stomach, duodenum, jejunum, ileum, colon, and rectum. METHODS: Microbiota of selected healthy volunteers from the oral cavity (n=10), the esophagus (n=10), the upper digestive tract (n=20), and the lower digestive tract (n=24) were evaluated through distinct collection methods. Collection methods took into account the different sites, using basic scraping and swabbing techniques, stimulated saliva from the oral cavity, irrigationaspiration with sterile catheters especially designed for the esophagus, a probe especially designed for upper digestive tract, and a special catheter for the lower digestive tract. RESULTS: (i) Mixed microbiota were identified in the oral cavity, predominantly Gram-positive aerobic and anaerobic cocci; (ii) transitional flora mainly in the esophagus; (iii) Veillonella sp, Lactobacillus sp, and Clostridium sp in the stomach and duodenum; (iv) in the jejunum and upper ileum, we observed Bacteroides sp, Proteus sp, and Staphylococcus sp, in addition to Veillonella sp; (v) in the colon, the presence of "nonpathogenic" anaerobic bacteria Veillonella sp (average 10 5 UFC) indicates the existence of a low oxidation-reduction potential environment, which suggests the possibility of adoption of these bacteria as biological markers of total digestive tract health. CONCLUSIONS: The collection methods were efficient in obtaining adequate samples from each segment of the total digestive tract to reveal the normal microbiota. These procedures are safe and easily reproducible for microbiological studies.

The secretion of gut hormones in patients with weight regain after RYGB is different from that in patients with satisfactory weight outcome. After meal stimulation, reduced levels of GIP and GLP-1 may indicate the influence of gut hormones in the process of weight regain.

Long-term follow-up (5 to 9 years) after the RYGBP was associated with satisfactory mantainance of EWL, and resolution or improvement of the main co-morbidities was observed in the majority of the patients.

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