Intestinal Calcium Absorption Decreases Dramatically After Gastric Bypass Surgery Despite Optimization of Vitamin D Status.

ABSTRACT: Roux-en-Y gastric bypass (RYGB) surgery has negative effects on bone, mediated in part by effects on nutrient absorption. Not only can RYGB result in vitamin D malabsorption, but the bypassed duodenum and proximal jejunum are also the predominant sites of active, transcellular, 1,25(OH)2 D-mediated calcium (Ca) uptake. However, Ca absorption occurs throughout the intestine, and those who undergo RYGB might maintain sufficient Ca absorption, particularly if vitamin D status and Ca intake are robust. We determined the effects of RYGB on intestinal fractional Ca absorption (FCA) while maintaining ample 25OHD levels (goal ?30?ng/mL) and Ca intake (1200?mg daily) in a prospective cohort of 33 obese adults (BMI 44.7?±?7.4?kg/m(2)). FCA was measured preoperatively and 6 months postoperatively with a dual stable isotope method. Other measures included calciotropic hormones, bone turnover markers, and BMD by DXA and QCT. Mean 6-month weight loss was 32.5?±?8.4?kg (25.8%?±?5.2% of preoperative weight). FCA decreased from 32.7%?±?14.0% preoperatively to 6.9%?±?3.8% postoperatively (p?

SUBMITTER: Schafer AL 

PROVIDER: S-EPMC4593653 | biostudies-literature | 2015 Aug

REPOSITORIES: biostudies-literature