gastric bypass bariatric surgery

Last edited 01/2019 and last reviewed 10/2021

Description of procedure:

• a gastric pouch is created at the top of the stomach, either by stapling or vertically banding most of the stomach or by removing portions of the stomach
• the gastric pouch is then connected to the small intestine, thereby bypassing the duodenum and some or all of the jejunum
• very effective at weight loss and may be the best option in diabetes and acid reflux (1)
• disadvantages include:
  • risks of surgery are higher than for simpler operations, it is essentially irreversible and you will need to take daily vitamin supplements for life after surgery (1)
  • obstruction can occur at the sites of formation of modified GI tract
  • patients may develop gallstones due to rapid weight loss (2)
  • flatulence and loose stools may be experienced especially if dietary changes have not been made to low fat, low sugar choices
  • dumping syndrome may occur if a patient eats too much sugar, fat or alcohol, or large amounts of food
    • not considered a health risk, but can be very unpleasant with symptoms including nausea, vomiting, diarrhoea, sweating, faintness, weakness and tachycardia

Impact on nutrition:

• impacts on the absorption of iron, vitamin B12, calcium and vitamin D
• long limb bypasses may affect absorption of protein, fat, vitamin A and trace elements in addition

Reference:

• North Bristol NHS Trust. Bariatric Surgery (Accessed January 8th 2019).
• Chelsea and Westminister NHS Hospitals Trust. Weight Loss - Surgical Options (Accessed January 8th 2019)
• BOMSS Guidelines on perioperative and postoperative biochemical monitoring and micronutrient replacement for patients undergoing bariatric surgery September 2014