Serum 25-Hydroxyvitamin D Levels After Bariatric Surgery

Abstract

© 2014, Springer Science+Business Media New York. Vitamin D deficiency is common after Roux-en-Y gastric bypass surgery, as malabsorptive component of the procedure affects its absorption, and dietary intake is inadequate due to restricted postoperative diet. Obesity itself is associated with low 25-hydroxy vitamin D levels due to larger volume of distribution with increased body fat mass, and studies have confirmed the presence of fat-soluble vitamin D in human adipose tissue. Massive weight loss after gastric bypass surgery is associated with an increase in serum 25-hydroxy vitamin D levels; however, the effect is small, and thus supplementation remains the mainstay of treatment and prevention of vitamin D deficiency in this population. Higher doses of vitamin D are often required, as most patients remain obese after bariatric surgery, and its absorption is reduced. Guidelines recommended supplementing bariatric patients with at least 3,000 IU per day of vitamin D, while doses as high as 50,000 IU 1–3 times weekly may be required in some patients.