The primary aim of the study is to analyse the micro-nutritional status in morbidly obese patients before and 6 months after bariatric surgery (Roux-en-Y gastric bypass, RYGB). The secondary outcome will be the impact of 6 months probiotics, minerals, aminoacids, omega-3 acids and vitamin supplementation on microbiota, metabolic and psychological parameters 12 months post-RYGB.~An intervention study in 90 obese patients (BMI>40 kg/m2) will be used. Nutritional, metabolic and psychological status as well as gut microbiota will be evaluated before gastric bypass and 6 months post RYGB. During this period of 6 months, all patients will receive a specific diet according to recommendation with regard to RYGB.~Subjects will be than randomized in 2 sub-groups:~A. patients receiving a standard healthy diet without micro-nutriments' supplementation; B. patients receiving a healthy diet and probiotics, minerals, aminoacids, omega-3 acids vitamin and mineral supplementation Healthy diet will be defined as follow: 9-15% of proteins, 50-55% of carbohydrates and 30-35% lipids (25% saturated fat, 50% mono-unsaturated fat and 25% poly-unsaturated fat).~The following parameters will be analysed before RYGB and 6 months and 12 months post RYGB, respectively:~Nutritional status with oxidative stress parameters (Vitamins A and E, Selenium, Zinc, Copper, Glutathione peroxidise, Superoxide dismutase and Iron)~Metabolic parameters (Total cholesterol, LDL-cholesterol, HDL-cholesterol, Triglycerides, fasting glucose and insulin, CRP)~Fatty acids (linoleic acid, alpha-linoleic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA)~Gut microbiota~Psychological status (anxiety, depression and quality of life as evaluated by validated questionnaires).
An intervention study design in 90 obese patients will be used. Nutritional, metabolic and psychological status as well as gut microbiota will be evaluated before gastric bypass and 6 months post surgery. During this period of 6 months, all patients will receive a specific diet according to recommendation with regard to bariatric surgery.~Subjects will be than randomized in 2 sub-groups:~A. patients receiving a standard healthy diet without micro-nutriments' supplementation; B. patients receiving a healthy diet and probiotics, minerals, aminoacids, omega-3 acids vitamin and mineral supplementation