Vitamin Status of Obese Tunisian adults before and after Sleeve Gastrectomy


Faten Mahjoub
Sarra Khlifi
Rim Rachdi
Nadia Ben Amor
Ramla Mizouri
Marwa Omri
Henda Jamoussi


Introduction: The worldwide obesity epidemic continues unabated. Obesity and its associated health risks are considered as the major causes of morbidity and mortality. Currently, bariatric surgery is the most effective treatment for people with severe obesity resulting in sustainable weight loss and a reduced risk for co-morbidities. Sleeve gastrectomy is the most common bariatric procedure undertaken in Tunisia.

Aim: we aim to evaluate the vitamin status of the obese patients before and after sleeve gastrectomy.

Methods: Thirty obese patients undergoing sleeve gastrectomy, were recruited from Obesity unit. In this study. A biological assessment was performed pre-operatively and controlled 6 months following the sleeve gastrectomy including: calcemia, parathyroid hormone (PTH), albuminemia and dosage of vitamin D, vitamin B9 and vitamin B12. 

Results: Six months post sleeve gastrectomy, vitamin deficiencies were more prevalent: the mean level of vitamin B9, vitamin B12 and vitamin D respectively, has decreased from 5.03±3.28 ng / ml to 2.71±1.52 ng / ml, from 348.06±158.92 pg/ml to 264.62±119.77 pg/ml and from 17.18±11.45 ng/ml to 11.69±8.22 ng/ml, with a statistically significant difference (p=0.008, p=0.01 and p=0.012). Sleeve gastrectomy has proven to be an effective weight loss treatment. However, nutritional deficiencies have worsened during postoperative period.

Conclusion: This study highlights the importance of early identification, appropriate treatment and prophylactic micronutrient supplementation.


Obesity, Sleeve gastrectomy, Vitamin D, Vitamin B9, Vitamin B12, Nutritional deficiencies



  1. Kamoun M, Hajem S, Imen S, Achour N, Slimane H. Prevalence of obesity and overweight in Tunisia on 2001. Tunis Med. 2008;86:649-52.
  2. El Ati J, Traissac P, Delpeuch F, Aounallah-Skhiri H, Béji C, Eymard- S, et al. Gender obesity inequities are huge but differ greatly according to environment and socio-economics in a North African setting: A national cross-sectional study in Tunisia. PloS One. 2012;7(10):48-153.
  3. Tunisian Health Examination Survey 2016. Available from:
  4. Poitou C, Ciangura C. Les déficits vitaminiques après chirurgie gastrique. Med Mal Metab. 2008;2(5):484-8.
  5. Damms-Machado A, Friedrich A, Kramer KM, Stingel K, Meile T, Kuper MA, et al. Pre-and Postoperative Nutritional Deficiencies in Obese Patients Undergoing Laparoscopic Sleeve Gastrectomy. Obes. Surg. 2012;22(6):881-9.
  6. Darmon P, Singer M, Boullue S. Carence nutritionnelle après Sleeve Gastrectomie et By-pass gastrique. Med. Mal. Metab. 2016;10(3):219-25.
  7. Haute Autorité de Santé. Obésité: prise en charge chirurgicale chez l’adulte. Recommandations pour la pratique clinique. Paris: HAS; 2009.
  8. Mechanick JI, Youdim A, Jones DB, Garvey WT, Hurley DL, Mcmahon M, et al. Clinical practice guidelines for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient—2013 update: cosponsored by American Association of Clinical Endocrinologists, the Obesity Society, and American Society for Metabolic & Bariatric Surgery. Surg. Obes. Relat. Dis. 2013; 9(2):159-91.
  9. World Health Organisation. Obesity: preventing and managing the global epidemic. Report of a WHO Consultation. WHO Technical Report Series 894. Geneva: World Health Organization, 2000.
  10. N. Bigé et JR. Lavillegrand. Dyscalcémies. Réanimation, chapitre 243, 1-19. Elsevier Mason 2020.
  11. Thakker RV. The parathyroid glands, Hypercalcemia, and Hypocalcemia. Goldman-Cecil Mdecine, 232, 1611.e2. Elsevier Masson 2020.
  12. Benhamou CL, Souberbielle JC, Cortet B, Fardellone P, Gauvain JB, Thomas T. La vitamine D chez l’adulte : recommandations du GRIO. Presse Med. 2011;40:673-82.
  13. Quilliot D, Sirveaux MA, Ziegler O, Reibel N, Brunaud L. Carences en vitamines, minéraux et éléments traces et dénutrition après chirurgie de l’obésité. Nutr Clin Metab. 2017;31:309-20.
  14. Moizé V, Andreu A, Flores L, Torres F, Ibarzabal A, Delgado S, et al. Long-Term Dietary Intake and Nutritional Deficiencies following Sleeve Gastrectomy or Roux-En-Y Gastric Bypass in a Mediterranean Population. Journal of the Academy of Nutrition and Dietetics. 2013;113(3):400-10.
  15. Nie Y, Tian Z, Wang P, Liu B, Zhang N, Zhou B et al. Prevalence of anemia and related nutrient deficiencies after sleeve gastrectomy: A systematic review and meta‐analysis. Obesity Reviews. 2023;24(1): e13516.
  16. Van Rutte PW, Aarts EO, Smulders JF, Nienhuigs SW. Nutrient deficiencies before and after sleeve gastrectomy. Obes. Surg. 2014;24(10):1639-46.
  17. Aarts EO, Janssen IM, Berends FJ. The Gastric Sleeve: Losing Weight as Fast as Micronutrients? Obes. Surg. 2011; 21(2):207-11.
  18. Allen LH. Causes of vitamin B12 and folate deficiency. Food Nutr Bull. 2008;29 (Suppl2):S20-S34.
  19. Ziegler O, Sirveaux MA, Brunaud L, Reibel N, Quilliot D. Medical follow-up after bariatric surgery: nutritional and drug issues. General recommendations for the prevention and treatment of nutritional deficiencies. Diabet Metab. 2009;35:544-57.
  20. Hakeam AH, O’Regan PJ, Salem AM, Bamehriz FY, Eldali AM. Impact of Laparoscopic Sleeve Gastrectomy on Iron Indices: 1 Year Follow-Up. Obes. Surg. 2009;19(11):1091-6.
  21. Kehagias I, Karamanakos SN, Argentou M, Kalfarentwos F. Randomized clinical trial of laparoscopic Roux-en-Y gastric bypass versus laparoscopic sleeve gastrectomy for the management of patients with BMI < 50 kg/m2. Obes.Surg. 2011;21:1650-6.
  22. Mulita F, Lampropoulos C, Kehagias D, Verras G-I, Tchabashvili L, Kaplanis C et al. Long-term nutritional deficiencies following sleeve gastrectomy: A 6-year single-centre retrospective study. Prz Menopauzal. 2021;20:170-6.
  23. Rashnoo F, Seifinezhad A, Zefreh H, Sheikhbahaei E, Irajpour AH. The Effect of Laparoscopic Sleeve Gastrectomy on Serum Levels of Vitamin A, D and B12 and Iron Profile on Patients with Morbid Obesity. Advanced Biomedical Research. 2023;12(1):211.
  24. Karefylakis C, Naslund I, Edholm D, Sundbom M, Karlsson FA, Rask E. Prevalence of anemia and related deficiencies 10 years after gastric bypass – a retrospective study. Obes. Surg. 2015; 5(6):1019-23.
  25. Aaseth JO, Alexander J. Postoperative Osteoporosis in Subjects with Morbid Obesity Undergoing Bariatric Surgery with Gastric Bypass or Sleeve Gastrectomy. Nutrients. 2023;15(6):1302.
  26. Melissas J, Daskalakis M, Koukouraki S, et al. Sleeve gastrectomy-a “food limiting” operation. Obes Surg. 2008;18(10):1251-6.
  27. Snyder-Marlow G, Taylor D, Lenhard MJ. Nutrition care for patients undergoing laparoscopic sleeve gastrectomy for weight loss. J Am Diet Assoc. 2010;110(4):600-7
  28. Gehrer S, Kern B, Peters T, Christoffel-Courtin C, Peterli R. Fewer nutrient deficiencies after laparoscopic sleeve gastrectomy (LSG) than after laparoscopic Roux-Y-gastric bypass (LRYGB)-A prospective study. Obes Surg. 2010;20(4):447-53.
  29. Holick MF. Vitamin D Deficiency. N Engl J Med. 2007;357:266-81.
  30. Giustina A, Di Filippo L, Facciorusso A, Adler RA, Binkley N, Bollerslev J et al. Vitamin D status and supplementation before and after Bariatric Surgery: Recommendations based on a systematic review and meta-analysis. Reviews in Endocrine and Metabolic Disorders. 2023;1-19.