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BYM [Bypass and Sleeve gastectomy (Bypass y Manga)]: Mineral absorption and mineral nutritional status in patients with severe and morbid obesity - effects of gastric bypass and sleeve gastrectomy
ISRCTN ISRCTN31937503
DOI 10.1186/ISRCTN31937503
ClinicalTrials.gov identifier
EudraCT number
Public title BYM [Bypass and Sleeve gastectomy (Bypass y Manga)]: Mineral absorption and mineral nutritional status in patients with severe and morbid obesity - effects of gastric bypass and sleeve gastrectomy
Scientific title Studies of the effects of Roux-en-Y gastric bypass and sleeve gastrectomy in morbid obesity on mineral and absorption and metabolism: cellular mechanisms involved
Acronym BYM
Serial number at source Fondecyt 1080576
Study hypothesis 1. Roux-en-Y gastric bypass (RYGBP) will have a greater effect on iron (Fe), zinc (Zn), copper (Cu) and calcium (Ca) nutritional status than sleeve gastrectomy (SG). In both types of surgery the effects will be more profound after 12 than 24 months of the intervention.
2. The intestinal absorption of zinc, calcium, heme iron, and non-heme iron will be decreased after RYGBP and SG. Such impairment will be more important after RYGBP than after SG and in both cases decreased absorption will be greater after 12 than 24 months of surgery.
3. Twelve months after SG, gene expression of Zn, Fe, Cu and Ca transporters will be increased in duodenal mucosa with respect to pre surgery values.
4. Twelve months after RYGBP gene expression of Zn, Fe, Cu and Ca transporters in jejunum mucosa close to the stomach will tend to mimic gene expression of transporters observed in duodenal mucosa.
5. Twelve and 24 months after RYGBP and SG bone mineral density will be decreased compared to pre surgery values. This change will be related to increased adiponectin and decreased ghrelin plasma concentrations and it will be independent of calcium intake and absorption.
Lay summary Background and study aims
Weight loss surgery (also called bariatric surgery) is the method that currently works best to induce sustained weight loss in severe and morbid obese individuals. Roux-en-Y gastric bypass (RYGBP) and sleeve gastrectomy (SG) are among the most commonly used techniques. RYGBP is a restrictive and malabsorptive technique (malabsorption means that the body does not absorb certain nutrients), whereas SG is a restricted only approach. Knowledge regarding the effects of bariatric surgery on absorption and metabolism of minerals, as well as cellular and molecular mechanisms involved is limited.
This research aims to study the mechanisms through which Roux-en-Y gastric bypass and sleeve gastrectomy affect absorption, metabolism and the nutritional status of selected minerals.

Who can participate?
Subjects will be recruited among women with residence in Santiago, Chile, starting in March 2008.

What does the study involve?
The study will be carried out in adult pre menopausal women with body mass index (BMI) > 35 kg/m2plus some co-morbidities such as hypertension, diabetes, insulin resistance, sleep apnea, dyslipidemia or BMR > 40 kg/m2regardless the presence of co-morbidities, using a contraceptive method (IUD, oral contraceptives or tubal ligation). Patients will be evaluated from the period immediately before, until 12 and 24 months after the surgery. The patientís doctor will decide whether the patient is treated by RYGBP or SG.
Before and after 12 and 24 months of RYGBP and SG, Zn, heme iron, non-hem iron, and calcium absorptions will be evaluated, besides, a series of determinations related to nutritional status of Zn, Fe, Cu and Ca will be carried out. Other determinations include body composition, bone mineral density, and plasma hormones such as adiponectin and ghrelin. Before and after 12 months of surgery gene expression of mineral-related cell transporters will be determined in intestinal mucosa and peripheral mononuclear cells.

What are the possible benefits and risks of participating?
Benefits include the results of a comprehensive description of patientsí Zn, Fe, Ca, and Cu nutritional status during the first two years after surgery, which may be useful for further adjustment of their nutritional management.
Risks involve the potential inconveniences related to surgical procedures, all of them explained in detail in the informed consent form.

Where is the study run from?
All procedures on the patients will be carried out at the Department of Nutrition, Faculty of Medicine, University of Chile, Santiago, Chile.

When is the study starting and how long is it expected to run for?
The study started in March 2008 and is expected to be completed in November 2012.

Who is funding the study?
The study is funded by the National Fund for the Development of Science and Technology (Fondecyt), Chile.

Who is the main contact?
Dr Manuel Ruz
mruz@med.uchile.cl
Ethics approval 1. Ethics Committee for Research in Humans from the Faculty of Medicine of the University of Chile, 12 July 2007, ref: 1296
2. Advisor Ethics committee of the Granting Agency (Fondecyt), 18 March 2008
Study design Interventional non-randomized parallel two arms
Countries of recruitment Chile
Disease/condition/study domain Severe and morbid obesity
Participants - inclusion criteria 1. Adut pre-menopausal women with body mass index (BMI) > 35 plus some co-morbidities such as hypertension, diabetes, insulin resistance, sleep apnea, dyslipidemia or BMR > 40 regardless the presence of co-morbidities
2. Indication of Roux-en-Y gastric bypass or sleeve gastrectomy
3. The use of a contraceptive method (IUD, oral contraceptives or tubal ligation), will be required prior to participation in the studies due to the use of radioactive isotopes. Furthermore, a pregnancy test will be conducted before the study
4. Consent to participate
Participants - exclusion criteria 1. Record of inflammatory bowel disease
2. Malabsorption syndrome
3. Liver or pancreatic disease
4. Chronic anemia
5. Low adherence to previous medical treatments
6. Pregnancy
Anticipated start date 18/03/2008
Anticipated end date 30/11/2012
Status of trial Completed
Patient information material Not available in web format, please use the contact details below to request a patient information sheet
Target number of participants 40
Interventions The decision in terms of what type of surgical procedure the patient will undergo ( Roux-en-Y gastric bypass or sleeve gastrectomy) is made by the patientís surgeon. After the surgery the individuals receive two types of supplements as detailed later; because RYGBP is a restrictive-malabsorptive procedure amounts of micronutrients is greater than that of sleeve gastrectomy.
1. RYGBP group: A vitamin-mineral supplement (Maltofer vit® Andromaco Laboratories, Santiago, Chile (1 tablet/d) + a Calcium and vitamin D supplement (Elcal D-PLUS® Andromaco Laboratories, Santiago, Chile) (1 tablet/d).
2. SG group: A vitamin-mineral supplement (Centrum® Wyeth laboratories, St Laurent, Montreal, Canada) (1 tablet/d) + a specially designed mineral capsule containing 22 mg Fe, 8.5 mg Zn, and Cu 1.1 mg (1 capsule/d) + a Calcium and vitamin D supplement (Elcal D-PLUS® (1 tab/d).
The composition of each supplement is shown in the following table

Daily supply of selected micronutrients provided to obese women after Sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB)
SG - RYGBP
Calcium (mg) 662 - 750
Mg mg 100 - 30
Zinc (mg) 15 - 25
Iron (mg) 36 - 60
Copper (ug) 1800 - 3000
Selenium (ug) 25 - 0
Manganese (mg) 2.5 - 5
Iodine (ug) 150 -200
Chromium (ug) 25 - 50
Molibdenum (ug) 25 - 50
Beta carotene (mg) 600 - 0
Vitamin C (mg) 60 -100
Vitamin E (mg) 15 - 30
Folic acid (ug) 200 -1000
Thiamin (mg) 1.4 - 3
Riboflavin (mg) 1.6 - 3
Vitamin B6 (mg) 2 -10
Vitamin B12 (ug) 1 -10
Niacin (mg) 18 - 30
Biotin (ug) 150 - 100
Panthotenic acid (mg) 6 -7
Vitamin A (ug) 600 - 1200
Vitamin D (IU) 600 - 800
Primary outcome measure(s) 1. Zn and Ca determined by the use of stable isotopes
2. Hem Fe and non-hem Fe absorption determined by the use of radioactive isotopes
3. Zn status (Plasma Zn, hair Zn, rapidly exchangeable zinc pool EZP)
4. Ca status (PTH, serum Ca and vitamin D)
5. Fe status (Hemoglobin, hematocrit, zinc-protoporphyrin, serum ferritin, serum transferrin receptor and
6. Cu status (plasma Cu)

Measured before and 12 and 24 months after surgery
Secondary outcome measure(s) 1. Hormone (ghrelin and adiponectine concentrations) measured before and 12 and 24 months after surgery
2. Body composition and bone mineral density (by DEXA) measured before and 12 and 24 months after surgery
3. Mieral-related gene expression (Ca: TRPV5 and TRPV6; Fe: DMT1 and FPN1; Zn: Zip 4 and ZnT1; Cu: hCTR1 and ATP7A) intestinal biopsies before and 12 months after surgery
Sources of funding National Fund for the Development of Science and Technology (FONDECYT) (Chile) ref: 1080576
Trial website
Publications 1. 2012 results in http://www.ncbi.nlm.nih.gov/pubmed/22952172
Contact name Dr  Manuel  Ruz
  Address Department of Nutrition
Faculty of Medicine
University of Chile
Independencia 1027
  City/town Santiago
  Zip/Postcode 8380453
  Country Chile
  Tel 562-9786134
  Fax 562-7378778
  Email mruz@med.uchile.cl
Sponsor University of Chile (UK)
  Address Department of Nutrition
Faculty of Medicine
Independencia 1027
  City/town Santiago
  Zip/Postcode 8380453
  Country Chile
  Sponsor website: http://med.uchile.cl
Date applied 26/06/2012
Last edited 20/11/2012
Date ISRCTN assigned 20/08/2012
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