From the Guidelines
Gastric sleeve surgery can cause iron deficiency and vitamin B12 deficiency due to reduced stomach size and decreased acid production, which impairs the absorption of these essential nutrients. After this procedure, patients have a higher risk of developing iron deficiency anemia because of low dietary iron intake, reduced intestinal absorption, and menstruation in women 1. Vitamin B12 absorption is also adversely affected by gastric sleeve surgery, as it requires an acidic environment and the presence of intrinsic factor produced by the gastric parietal cells 1.
Some key points to consider:
- Iron deficiency occurs because the surgery removes part of the stomach that produces acid needed to convert dietary iron into an absorbable form 1.
- Vitamin B12 deficiency happens because there's less intrinsic factor produced, which is necessary for B12 absorption 1.
- Most patients require lifelong supplementation after gastric sleeve surgery, including a daily multivitamin containing iron (18-60 mg elemental iron daily) and vitamin B12 supplementation (500-1000 mcg orally daily or 1000 mcg monthly injections) 1.
- Blood tests should be performed regularly, typically every 3-6 months in the first year after surgery and annually thereafter, to monitor nutrient levels 1.
- Early symptoms of deficiency include fatigue, weakness, and pale skin for iron deficiency, and numbness, tingling in hands and feet, memory problems, and fatigue for B12 deficiency 1.
It is essential to note that patients should take supplements consistently and follow up with healthcare providers to prevent these nutritional complications. Additionally, a balanced diet with high protein content, avoidance of high-calorie-dense foods and beverages, and sufficient drinking and chewing are recommended to prevent other nutritional deficiencies and promote overall health 1.
From the Research
Gastric Sleeve Surgery and Nutrient Deficiencies
- Gastric sleeve surgery can lead to iron deficiency and vitamin B12 deficiency, as evidenced by studies that have investigated the effects of this type of surgery on nutrient levels 2, 3, 4.
- A study published in 2013 found that 20% of patients who underwent laparoscopic sleeve gastrectomy (LSG) had vitamin B12 deficiency, highlighting the need for postoperative monitoring and supplementation 2.
- Another study published in 2011 found that 43% of patients who underwent LSG had iron deficiency, and 9% had vitamin B12 deficiency, emphasizing the importance of regular blood testing and supplementation 3.
Comparison with Other Bariatric Surgeries
- A meta-analysis published in 2014 compared the risk of postoperative anemia and nutritional deficiencies between sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB), and found that SG was associated with a lower risk of vitamin B12 deficiency 4.
- A histological study published in 2017 found that the stomach's ability to regenerate and increase its surface area may help to limit vitamin B12 deficiencies in patients who undergo SG, compared to those who undergo RYGB 5.
Recommendations for Patients Undergoing Gastric Sleeve Surgery
- Patients who undergo gastric sleeve surgery should be monitored regularly for iron and vitamin B12 deficiencies, and supplemented as needed 3, 4.
- A multivitamin and mineral supplement regimen should be regarded as a minimum, with additional supplements for iron, vitamin B12, and other nutrients as needed, based on regular blood testing 3, 4.