Long-term complications after gastric bypass and sleeve gastrectomy: What information to give to patients and practitioners, and why?

Bariatric surgery is now recognized as the most effective treatment of morbid obesity, leading to durable weight loss and resolution of associated co-morbidities. Roux-en-Y gastric bypass and sleeve gastrectomy are the two most widely used operations today. However, potentially serious medical, surgical, and/or psychiatric complications can occur that raise questions regarding the benefits of this type of surgery. These complications can lead to surgical re-operations, iterative hospitalizations, severe nutritional deficiencies and psychological disorders. Indeed, death from suicide is said to be three times higher than in non-operated obese patients. These results are of concern, all the more because of the high prevalence of patients lost to follow-up (for various and multifactorial reasons) after bariatric surgery. However, better knowledge of post-surgical sequelae could improve the information provided to patients, the preoperative evaluation of the benefit/risk ratio, and, for patients undergoing surgery, the completeness and quality of follow-up as well as the detection and management of complications. The development of new strategies for postoperative follow-up such as telemedicine but also the mobilization of all the actors along the healthcare pathway can make inroads and warrant further study.

Effect of proteins on availability of zinc. II. Bioavailability of zinc from casein and whey protein--retention study in young rats

The availability of zinc from two semi-synthetic diets with isolated whey protein (Wp D) or with isolated casein (Cas D) as protein component (20% W/W) was compared in a 21-day study with growing male rats (initial weight 40 g; 14 animals/group). Zinc concentration in both diets (18 ppm) was adequate to meet the requirements of the animals fed ad libitum. For radiolabeling approximately 13 micrograms 65Zn (= 4 microCi) was given daily by intragastric intubation to each animal. The investigation was designed primarily as a retention study, but also general parameters like weight development, food and water intake, organ weights etc. were registered and the activity of alkaline phosphatase was determined in serum and femur tissue. A significantly higher percentage of 65Zn was retained in the whole body from the Wp D (36.5%) than from the Cas D (31.6%) during the experimental period. The same is valid for the percentage retention of 65Zn in the femur and for the 65Zn concentration in femur and hair as well as for the total zinc concentration (65Zn and non-labeled zinc) of the femur. The other parameters determined were not unequivocally influenced by the protein component of the diet. The study clearly demonstrated that the availability of zinc by the growing rat was better from a diet with whey protein than from one with casein as the protein component. The reason on this phenomenon has to be elucidated by further investigations.

Effect of proteins on availability of zinc. I. Gastrointestinal transit time of casein and whey protein and zinc absorption in weaned rats

The availability of zinc from isolated casein (CasD) was compared with that from whey protein (WpD) in 23-25 day old rats. The study was designed to show the course of the gastrointestinal transit time of either chyme (radiolabeled by 141Ce as a non-absorbable marker) or zinc (as 65Zn) in groups of 9 to 12 animals each. Animals were killed either 1/4, 1/2, 1, 2, 6, 12 or 24 hours after intragastric intubation of the protein suspensions. Immediately afterwards, intragastric pH was measured and the determination of zinc retention in intestinal tissues and liver as well as in the carcass was performed. 30 and 60 minutes after intubation the intragastric pH of the CasD group was significantly lower than that of the WpD group. The precipitation behaviour of the two protein fractions - compact curd formation by the CasD versus flocculent structure of the WpD - was determining for the pattern of gastric emptying. With the WpD the chyme was emptied according to an exponential function; while the CasD precipitate left the stomach in three distinct phases. With either protein suspension zinc left the stomach ealier than the bulk of the chyme, indicating a partial disintegration of the zinc-protein-complexes. With the WpD, zinc was emptied exponentially, whereas with the CasD a biphasic emptying pattern was found. Ileum was found to be the main zinc absorbing segment, mainly due to the long time of contact with zinc. After 2 and 12 hours zinc retention from the CasD was significantly higher than that from the WpD, however, after 24 hours retention was significantly better from the WpD. From the present study it can be concluded that, for comparison of zinc availability from diets containing different proteins, short-term experiments are not appropriate. Furthermore, it can be supposed that preabsorptive processes in the stomach are crucial for the availability of zinc.