Bariatric/metabolic surgery (BMS) can lead to several nutritional deficiencies and can worsen pre-existing ones. The aim of this study was to analyze the changes of nutrients before and after BMS in Korean patients.


This study included patients who underwent adjustable gastric banding (AGB), sleeve gastrectomy (SG), and Roux-en Y gastric bypass (RYGB) via laparoscopy in a single institution in Korea, followed up for at least one year. The blood test values of nutrients including iron, calcium, vitamin D, Vitamin B1/B12, folic acid, magnesium, and albumin before and after BMS were compared and analyzed by period and operation types.


From January 2013 to December 2017, 302 patients (F:M=256:46) with a mean age of 34.1±8.3 years and a preoperative BMI of 35.3±5.7 kg/m². As a result of analysis by period, hemoglobin (Hb) (14.1±1.4 vs. 13.3±1.3, p<0.001), Vitamin B1 (146.1±36.1 vs. 126.6±40.8, p=0.002), Vitamin B12 (574.5±387.4 vs. 461.8±176.9, p<0.001), and albumin (4.5±0.4 vs. 4.4±0.3, p<0.001) decreased significantly at 12th month. Meanwhile, there were no significant differences according to three operation types at 12th month. In the case of AGB, Hb, iron, vitamin B1, and magnesium were decreased, and decrease of Hb, and vitamin B1/B12 in SG, and decrease of vitamin B12 in RYGB were observed at 12th month compared with before surgery.


In conclusion, regular screening and supplementation of these nutrients are required after SG, RY, as well as after AGB. Further long-term follow-up results are needed to provide a strong evidence-based guideline tailored to Eastern post-bariatric patients.