Prevalence of Micronutrient Deficiency in Patients with Morbid Obesity Before Bariatric Surgery

Postoperative micronutrient deficiency is a known side effect of bariatric surgery. In this study, we examined the prevalence of micronutrient deficiency in patients with morbid obesity (MO) preoperatively.

A total of 1732 patients with MO wishing to undergo bariatric surgery (age: 40 ± 12 years, mean BMI: 44 ± 9 kg/m², means ± SD, 77.3% female) were analyzed in this cross-sectional examination. Iron state, vitamin B12, folic acid, 25hydroxy(OH)-vitamin D, PTH, vitamin A, and vitamin E levels were determined. Subsequently, patients underwent nutritional counseling and were substituted accordingly.

A total of 63.2% (n = 1094) of the patients had a deficit in folic acid (< 5.3 ng/ml), 97.5% (n = 1689) in 25OHvitamin D (< 75 nmol/l), and 30.2% (n = 523) had a PTH elevation (> 56.9 pg/ml). A total of 5.1% (n = 88) of the patients presented with a deficit in vitamin B12 (< 188 pg/ml) and 6.2% (n = 107) in vitamin A (< 1.05 μmol/l). A total of 9.6% (n = 166) exhibited iron deficiency (ferritin < 15 μg/l). None of the patients had a deficit in vitamin E. There were no gender differences except for ferritin deficiency (women 11.8% vs. men 1.5%, p < 0.001). Patients in the highest BMI tertile had significantly more often a deficit in vitamin D (p = 0.033) and folic acid (p < 0.001). Patients in the lowest age tertile had significantly more often a deficit in folic acid (p < 0.001).

Our data show a high prevalence of micronutrient deficiency in patients with morbid obesity preoperatively and emphasize the importance of exact preoperative evaluation and adequate substitution as well as postoperative surveillance.