Micronutrients Deficiencies in Candidates of Bariatric Surgery: Results from a Single Institution over a 1-Year Period

Background: Micronutrient deficiencies represent a common condition after bariatric surgery (BS). The prevalence of these nutritional disorders before BS is still debated. The aim of our study was to retrospectively evaluate the prevalence of micronutrient deficiencies in candidates for BS. Methods: A prospectively maintained database of our institution was searched to find all patients who underwent surgery between January and December 2021. The following data were collected: age, gender, body mass index (BMI), obesity-associated diseases, and preoperative serum levels of vitamin B12, folate, and vitamin D. Results: A total of 174 patients were included in our study. Mean age and BMI were 39.2 ± 11.4 years and 44.3 ± 7.1 kg/m², respectively. One hundred and thirty-nine patients (79.9%) had at least one preoperative micronutrient disorder, with vitamin D deficiency being the most common (116, 66.7%), followed by a deficit of folate (76, 43.7%) and vitamin B12 (10, 5.7%). Forty-seven (27%) individuals had insufficient levels of vitamin D. Comparison of deficiencies between sexes showed that vitamin B12 < 20 ng/ml was significantly more frequent in women (p = 0.03). DLP showed a mild significant effect on folate levels (p = 0.01), while the association of HNT and T2DM had a mild significant effect on vitamin B12 (p = 0.02). Conclusions: Preoperative micronutrient deficiencies were frequently found in candidates for BS. Approximately 90% of patients had deficient or insufficient serum levels of vitamin D preoperatively. Almost half of the patients had a preoperative deficit of folate, and vitamin B12 deficiency was significantly more frequent in the female population. It is mandatory to screen all patients undergoing BS for vitamin deficiencies before surgery.