title: Nutritional deficiencies in gastric bypass patients; incidence, time of occurrence and implications for post-operative surveillance.
abstract: BACKGROUND
  Post-operative nutritional deficiencies are a common complication following bariatric surgery. The incidence and time of occurrence are not clear, and the efficacy of supplementation remains questionable. Clear guidelines for nutritional follow-up and counselling are needed.
  
  
  METHODS
  Preoperative and post-operative deficiencies were determined in a group of 427 gastric bypass patients. The predictive value of preoperative laboratory findings for the development of post-operative deficiencies, the time of occurrence and the effect of supplementation of common deficiencies was studied.
  
  
  RESULTS
  Most common preoperative deficiencies were of folic acid (21.3%), vitamin D3 (17.5%) and iron (21.8%). Post-operative, a significant increase in the number of patients with anaemia and deficiencies of ferritin and vitamin B12 was found. Most deficiencies occur between 12 and 15 months post-operatively, but vitamin D3 deficiency occurs significantly earlier at 9.7 months. A preoperative iron, folic acid or ferritin deficiency results in a significant higher risk for developing a post-operative deficiency despite supplementation, and ferritin deficiency occurs significantly earlier in these patients. Oral treatment of post-operative vitamin B12 and vitamin D3 deficiencies was successful in more than 80% of the patients in contrast to oral treatment of anaemia which was only successful in 62.5% of the patients.
  
  
  CONCLUSIONS
  Our study emphasizes the importance of preoperative assessment and treatment of nutritional deficiencies in morbidly obese patients undergoing gastric bypass surgery. Despite limited efficacy, post-operative oral supplementation should be encouraged as it decreases the incidence of deficiencies.
authors.affiliation: Department of Plastic and Reconstructive Surgery, St. Antonius Hospital, Koekoekslaan 1, 3435 CM, Nieuwegein, The Netherlands, e.van.der.beek@antoniusziekenhuis.nl.
authors.forename: Eva S J
authors.initials: ES
authors.lastname: van der Beek
authors.forename: Valerie M
authors.initials: VM
authors.lastname: Monpellier
authors.forename: Ingo
authors.initials: I
authors.lastname: Eland
authors.forename: Ellen
authors.initials: E
authors.lastname: Tromp
authors.forename: Bert
authors.initials: B
authors.lastname: van Ramshorst
mesh_terms: D000328:Adult; D018798:Anemia, Iron-Deficiency / Q000209:etiology; D019587:Dietary Supplements; D005260:Female; D005293:Ferritins / Q000097:blood; D005492:Folic Acid / Q000097:blood; D015390:Gastric Bypass / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000453:epidemiology / Q000601:surgery; D011184:Postoperative Period; D012307:Risk Factors; D014806:Vitamin B 12 Deficiency / Q000453:epidemiology / Q000209:etiology; D014808:Vitamin D Deficiency / Q000209:etiology
chemical_list: D005293:Ferritins; D005492:Folic Acid