Efficacy of Vitamin D Supplementation Following Roux-En-Y Bypass and Gastric Sleeve Surgeries

Carolyn E Moore, PhD, RD, Monica Flinn, RN, Vadim Sherman, MD, FACS, FRCS

The Methodist Hospital and Texas Woman’s University, Houston, Texas

INTRODUCTION – The study goal was to determine the effectiveness of daily supplementation with 2,000 International Units (IUs) of vitamin D3 for preventing and treating vitamin D deficiency following bariatric surgery. Although vitamin D deficiency is common with bariatric surgery, there are few prospective studies evaluating appropriate levels of vitamin D supplementation to base recommendations.

METHODS – A prospective study was conducted with19 women undergoing bariatric surgery (11 Roux-en-Y bypass and 8 gastric sleeve). Women were excluded with hypercalcimia, hypocalcemia, renal insufficiency, or a history of primary hyperparathyroidism. Height, weight, body mass index (BMI), serum 25(OH)D, and serum PTH concentrations were measured at baseline and 3 months. Participants consumed 2000 IU of vitamin D3 and 1500 mg calcium citrate each day as chewable tablets (Celebrate ®). Serum 25(OH)D concentrations were measured by chemiluminescent immunoassay, and PTH levels were determined using the ADVIA Centaur ® Immunoassay System. To promote adherence, participants recorded dietary supplement intake on log sheets. Statistical analyses were performed with SPSS (version 19; SPSS IBM). Paired sample t -tests were used to compare body weight, 25(OH)D and PTH concentrations at baseline and 3 months. Assumptions for parametric statistic were met and all differences were considered significant at P < 0.05. Vitamin D deficiency was defined as a serum 25(OH)D concentration less than 20 ng/mL (50 nmol/L) and secondary hyperparathyroidism as ≥ 70 ng/L.

RESULTS – At baseline the majority of the women were vitamin D deficient (66%) and many had elevated PTH levels (42%). Following 3 months of supplementation with 2000 IU of vitamin D3 and 1500 mg calcium, serum 25(OH)D concentrations significantly increased from 18.7 ± 9.7 to 28.0 ± 8.8 ng/mL (P = 0.001) and mean PTH decreased from 67.5 ± 22.8 to 57.9 ± 20.3 ng/L (P = 0.292). By the end of 3 months, body weight decreased from 280 ± 56 lbs. to 247 ± 48 lbs. (P = 0.000) and BMI decreased from 47.1 ± 8.5 to 41.5 ± 8.0.

CONCLUSIONS – Prior to surgery, a majority of the women were vitamin D deficient. Low serum 25(OH)D concentrations are common in obesity and a negative relationship with body fat may be related to sequestration of vitamin D in adipose tissue. Daily supplementation with 2,000 IU of vitamin D3 following surgery for 3 months significantly increased 25(OH)D concentrations, reducing the percent of women who were vitamin D deficient from 66% to 21%. Furthermore, serum 25(OH)D concentrations did not reach levels that were associated with detrimental health effects. Nevertheless, several women remained vitamin D deficient and more aggressive supplementation may be indicated. Factors that increased the risk of vitamin D deficiency following bariatric surgery included the signification reduction of food intake and malabsorption specifically associated with the Roux-en-Y surgery. In summary, our findings support daily supplementation with 2,000 IU of vitamin D3 and 1500 mg calcium as an effective intervention following gastric sleeve and Roux-en-Y procedures. Moreover, we strongly support monitoring serum 25(OH)D and PTH concentrations post-operatively for the long-term prevention of metabolic bone disease.

Session: Poster Presentation

Program Number: P428

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