Prevalence of Vitamin and Mineral Deficiencies in Bariatric Patients Following the 2013 Updated Supplementation Guidelines
Authors: Megill Robin D , Peterson Leigh A , AlSulaim Hatim A , Carobrese Suzy , Schweitzer Michael A , Magnuson Thomas H , Steele Kimberley E 
Published: November 2023

Background

Bariatric surgery is the most effective obesity treatment. However, patients undergoing bariatric surgery are high‐risk for nutritional deficiencies, especially post‐operatively. In March 2013, the American Society for Metabolic and Bariatric Surgery (ASMBS) released updated nutritional supplementation guidelines with the goal of improving nutritional deficiencies following bariatric surgery.

Objective

To investigate the ability of the 2013 ASMBS standardized supplementation to adequately treat patients after bariatric surgery, including differences by procedure type and in fat and water soluble vitamins.

Methods

We retrospectively collected data on 105 patients undergoing Roux‐en‐y gastric bypass (RYGB) or vertical sleeve gastrectomy (VSG) using electronic medical records from February 2015 to September 2013, when the recommendations were implemented at our center. Labs were collected at 3 months, 6 months, and 1 year post‐operatively. Nutrition labs included fat soluble vitamins A, D, and E‐α; water soluble vitamins B1 (thiamine), folate, and B12; and iron studies. Other markers of malnutrition included albumin, prealbumin, and parathyroid hormone. Both clinical and frank deficiencies were examined. Univariate analysis was used to test for significant differences by procedure. Quantitative variables were analyzed as means with 95% confidence intervals, setting α=0.05.

Results

Fifty‐eight of the 173 patients examined were excluded due to missing nutrition labs. Of the 105 patients included, 34 (32.4%) underwent laparoscopic RYGB, 6 (5.7%) underwent open RYGB, 63 (60.0%) underwent laparoscopic VSG, and 2 (1.9%) underwent open VSG. We had follow up data for 81 (77.1%) at 3 months, 49 (46.7%) at 6 months, 58 (55.2%) at 1 year. Clinical and frank deficiencies were found in 74.3% and 34.3% of patients, respectively, most commonly in vitamin D, iron, and vitamin B1. Fat soluble deficiencies consistently occurred at twice the rate of water soluble. Patients undergoing RYGB or VSG were generally similar, differing significantly by diabetes, length of stay post‐operatively, and surgical approach (open or robotic). We found a general trend of more deficiencies following RYGB, with TIBC at 3 months, vitamin D at 6 months, and iron at 3 months and 1 year reaching statistical significance. The highest prevalence of deficiencies was seen at 6 months, immediately following the greatest weight loss (from 3 to 6 months).

Conclusions

We found an alarming 74.3% of patients in this cohort to have nutritional deficiencies following bariatric surgery despite the publication of the ASMBS supplemental guidelines. Furthermore, RYGB was associated with more nutrient deficiencies, more open surgeries, and longer length of stay. Patient follow up is of concern and may be indicative of poor adherence to the medical regimen. While further investigations may be warranted to improve supplementation guidelines, non‐compliance may account for some of the nutritional deficiencies. Supplementation guidelines are necessary; however, they are only effective if patients adhere to them. Further studies should investigate reasons for poor follow‐up in the bariatric surgical population and interventions that may improve adherence.