Vitamins Recommended After a Gastric Bypass

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Gastric bypass surgery helps morbidly obese patients lose significant amounts of weight. The nature of the surgery, however, increases the risk of vitamin and mineral deficiencies. In addition to limiting food intake by reducing the size of the stomach, the procedure reroutes the digestive system so that food bypasses the parts of the intestines where certain nutrients are normally absorbed. For these reasons, patients must take supplements to avoid deficiencies.

Vitamin B-12

The body needs vitamin B-12 for proper nerve functioning, making red blood cells and producing DNA and RNA. Vitamin B-12 comes from animal protein sources such as meat, fish, dairy products and eggs. Gastric bypass surgery impairs vitamin B-12 absorption from food and from some types of supplements, so patients must take vitamin B-12 nasally, under the tongue or by injection for the rest of their lives. Your surgeon will prescribe the correct dose for your individual needs.

Vitamin D

Vitamin D assists the body in absorbing calcium and distributing it to your bones; it also supports the immune system and plays a role in growth and development. Vitamin D comes from food and is also manufactured by the body after skin exposure to the sun. If you suffer from vitamin D deficiency, your bones may become weak and break easily. Bariatric surgeons generally instruct patients to take a calcium citrate compound with vitamin D, 2 to 3 times a day for the rest of their lives.


Because gastric bypass surgery affects absorption of food and reduces intake, patients may develop deficiencies of folate, thiamin and some minerals unless they take multivitamins for the rest of their lives. Look for a high-quality multivitamin that contains 200 percent of the daily value of at least two-thirds of the nutrients in the product, according to a study published in the September 2008 issue of "Surgery for Obesity and Related Diseases." Surgeons recommend starting with a chewable or liquid form until you can tolerate a capsule or tablet. The compound should also contain minerals including zinc and iron.