Fox A, Slater C, Ahmed B, Ammori BJ, Senapati S, Akhtar K, Ellison J, Summers LKM, Robinson A, New JP, Soran H, Adam S, Syed AA. Vitamin D status after gastric bypass or sleeve gastrectomy over 4 years of follow-up. Obes Surg 2019 | doi:10.1007/s11695-019-04318-0
Vitamin D levels are low in 4 in 5 people with obesity prior to bariatric surgery. Routine supplementation following bariatric surgery reduces rates of deficiency/insufficiency.