Bone and gastric bypass surgery: effects of dietary calcium and vitamin D.
OBJECTIVE
To examine bone mass and metabolism in women who had previously undergone Roux-en-Y gastric bypass (RYGB) and determine the effect of supplementation with calcium (Ca) and vitamin D.


METHODS
Bone mineral density and bone mineral content (BMC) were examined in 44 RYGB women (> or = 3 years post-surgery; 31% weight loss; BMI, 34 kg/m(2)) and compared with age- and weight-matched control (CNT) women (n = 65). In a separate analysis, RYGB women who presented with low bone mass (n = 13) were supplemented to a total 1.2 g Ca/d and 8 microg vitamin D/d over 6 months and compared with an unsupplemented CNT group (n = 13). Bone mass and turnover and serum parathyroid hormone (PTH) and 25-hydroxyvitamin D were measured.


RESULTS
Bone mass did not differ between premenopausal RYGB and CNT women (42 +/- 5 years), whereas postmenopausal RYGB women (55 +/- 7 years) had higher bone mineral density and BMC at the lumbar spine and lower BMC at the femoral neck. Before and after dietary supplementation, bone mass was similar, and serum PTH and markers of bone resorption were higher (p < 0.001) in RYGB compared with CNT women and did not change significantly after supplementation.


CONCLUSIONS
Postmenopausal RYGB women show evidence of secondary hyperparathyroidism, elevated bone resorption, and patterns of bone loss (reduced femoral neck and higher lumbar spine) similar to other subjects with hyperparathyroidism. Although a modest increase in Ca or vitamin D does not suppress PTH or bone resorption, it is possible that greater dietary supplementation may be beneficial.
Goode
Lisa R
LR
Department of Nutritional Sciences, Rutgers University, New Brunswick, New Jersey 08901, USA.
Brolin
Robert E
RE
Chowdhury
Hasina A
HA
Shapses
Sue A
SA
D000328:Adult; D015519:Bone Density; D016723:Bone Remodeling; D001842:Bone and Bones / Q000378:metabolism*; D002136:Calcium, Dietary / Q000008:administration & dosage*; D004032:Diet; D019587:Dietary Supplements; D005260:Female; D005500:Follow-Up Studies; D015390:Gastric Bypass / Q000009:adverse effects*; D006801:Humans; D008875:Middle Aged; D009765:Obesity / Q000601:surgery; D010281:Parathyroid Hormone / Q000097:blood; D017698:Postmenopause; D017697:Premenopause; D014807:Vitamin D / Q000008:administration & dosage* / Q000031:analogs & derivatives* / Q000097:blood; D015431:Weight Loss
D002136:Calcium, Dietary; D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D