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High prevalence of vitamin D deficiency among gastric bypass patients despite supplementation

Posted on: November 24, 2014   by  Vitamin D Council


A new study has found that there is a high prevalence of vitamin D deficiency among omega loop gastric bypass patients.

Gastric bypass surgery is used to lose weight rapidly by limiting how much a person can eat and decreasing the absorption of foods. The surgery is done when diet and exercise haven’t worked and someone’s health is in serious danger due to their weight.

Omega loop gastric bypass (OLGB) is a specific type of gastric bypass surgery that is also known as mini gastric bypass surgery.

Gastric bypass surgeries are highly effective at achieving weight loss, with patients losing an average of 60-80% of excess body weight. However, there are many complications associated with gastric bypass surgery, including nutrient deficiencies.

Bypassing a section of the small intestines can result in delayed mixing of digestive aids, such as enzymes and bile salts, with dietary fat. This leads to deficiencies in all of the fat soluble vitamins: D, E, A, and K.

Recently, researchers wanted to evaluate the effect of OLGB on vitamin D status. The researchers retrospectively analyzed the vitamin D status of 50 OLGB surgery patients before surgery and at 3, 6, and 12 months after the surgery.

They found that 96% of the patients were considered vitamin D deficient with vitamin D levels less than 30 ng/ml before the surgery.

All patients received vitamin D supplementation according to current guidelines after the surgery. The average vitamin D supplement was given as 200 IU/day at 3 months post-surgery, 1,294 IU/day at 6 months, and 1,411 IU/day at 12 months. Nonetheless, researchers found that 80% of the patients were vitamin D deficient a year after surgery.

Patients with a pre-operative BMI of above 45 were more than 3 times as likely to be deficient compared to those with a pre-operative BMI of below 45.

The researchers concluded, “Despite vitamin D supplementation following OLGB in morbidly obese subjects, the preoperatively high prevalence of vitamin D deficiency could not be adequately treated.”


Luger M, et al. Effects of Omega-Loop Gastric Bypass on Vitamin D and Bone Metabolism in Morbidly Obese Bariatric Patients. Obesity Surgery, 2014.

1 Response to High prevalence of vitamin D deficiency among gastric bypass patients despite supplementation

  1. John

    Does vitamin D produced from sunlight via the skin go through the intestines to get absorbed? D is so vital that there may be another mechanism than regular “vitamins” use to get absorbed.

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