Evidence for the necessity to systematically assess micronutrient status prior to bariatric surgery

Obes Surg. 2009 Jan;19(1):66-73. doi: 10.1007/s11695-008-9545-4. Epub 2008 May 20.


Background: Bariatric surgery has been proven the most effective treatment of morbid obesity, but micronutrient deficiency following bariatric surgery is a major concern. Increasing evidence points to a generally poor micronutrient status in obese subjects.

Methods: We assessed micronutrient status in 232 morbidly obese subjects (BMI > or = 35 kg/m(2)) prior to bariatric surgery. Serum albumin, calcium, phosphate, magnesium, ferritin, hemoglobin, zinc, folate, vitamin B(12), 25-OH vitamin D(3), and intact parathormone (iPTH) were determined. In a sub-sample of 89 subjects, we additionally assessed copper, selenium, vitamin B(1), B(3), B(6), A, and E levels.

Results: Deficiencies were found in 12.5% of the subjects for albumin, 8.0% for phosphate, 4.7% for magnesium, 6.9% for ferritin, 6.9% for hemoglobin, 24.6% for zinc, 3.4% for folate, and 18.1% for vitamin B(12). In addition, 25.4% showed a severe 25-OH vitamin D(3) deficiency, which was accompanied by a secondary hyperparathyroidism in 36.6% cases. Prevalence of albumin deficiency (p < 0.007) and of anemia (p < 0.003; in women only) significantly increased with BMI. Of note, 48.7% of the subjects showed at least one of the most prevalent deficiencies, i.e., vitamin B(12), zinc and severe 25-OH vitamin D(3) deficiency. In the sub-sample, 32.6% showed a selenium, 5.6% a vitamin B(3), 2.2% a vitamin B(6), and 2.2% a vitamin E deficiency. Copper, vitamin B(1), and vitamin A deficiency was found in none of the subjects.

Conclusion: Data indicate a high prevalence of micronutrient deficiencies in morbidly obese subjects. Based on these results, we strongly recommend a systematic assessment of the micronutrient status in all candidates for bariatric surgery.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Bariatric Surgery*
  • Body Mass Index
  • Cohort Studies
  • Deficiency Diseases / diagnosis
  • Deficiency Diseases / epidemiology*
  • Female
  • Humans
  • Male
  • Micronutrients*
  • Middle Aged
  • Needs Assessment
  • Nutritional Status*
  • Obesity, Morbid / complications*
  • Obesity, Morbid / metabolism
  • Obesity, Morbid / surgery
  • Prevalence
  • Risk Factors


  • Micronutrients