Micronutrients deficiences in patients after bariatric surgery

Eur J Nutr. 2022 Feb;61(1):55-67. doi: 10.1007/s00394-021-02619-8. Epub 2021 Jul 23.


Bariatric surgery is an effective option for managing obesity and has gained general acceptance among patients in recent years. Generally, despite the high caloric intake, a bad nutritional habit of obese people results in the deficiency of several vitamins, minerals, and trace elements essential for body metabolism and normal physiological processes. Additionally, the current bariatric surgical approaches such as sleeve gastrectomy (SG), Roux-en-Y-gastric bypass (RYGB), laparoscopic adjustable gastric banding (LAGB), and jejunoileal bypass (JIB) can cause or exacerbate these deficiencies. Based on several reports, it appears that the various bariatric surgical procedures affect nutrient absorption differently. Being purely restrictive, LAGB and SG affect the absorption of iron, selenium, and vitamin B12, while RYGB, JIB, and biliopancreatic diversion have a more profound impact on the absorption of essential vitamins, minerals, and trace elements. Nutritional deficiencies in vitamins, minerals, and trace elements may follow bariatric surgery and are associated with clinical manifestations and diseases, including anemia, ataxia, hair loss, and Wernicke encephalopathy. The present review summarizes some of the major vitamin and micronutrient deficiencies associated with bariatric surgery, particularly those presented post-surgically. To avoid any adverse consequences of vitamin and trace element deficiency, proper monitoring and tests are recommended at any stage, from pre- to post-surgery (periodical check-up), followed by specific and individual nutritional supplementation treatments and a proper healthy diet.

Keywords: Bariatric surgery; Micronutrients deficiency; Nutritional supplements; Trace elements deficiency; Vitamins deficiency.

Publication types

  • Review

MeSH terms

  • Bariatric Surgery*
  • Gastric Bypass* / adverse effects
  • Humans
  • Malnutrition*
  • Micronutrients
  • Obesity, Morbid* / surgery
  • Vitamins


  • Micronutrients
  • Vitamins