Vitamin Levels to Check After Roux-en-Y Bariatric Surgery
After Roux-en-Y gastric bypass surgery, patients should have regular monitoring of vitamin levels at 3,6, and 12 months in the first year and at least annually thereafter, including full blood count, ferritin, folate, vitamin B12, vitamin D, calcium, and renal and liver function tests. 1
Core Laboratory Monitoring Schedule
First Year Post-Surgery
- 3,6, and 12 months:
- Full blood count
- Ferritin and iron studies
- Folate
- Vitamin B12
- 25-hydroxyvitamin D
- Calcium
- Parathyroid hormone (if not checked prior to surgery)
- Urea and electrolytes
- Renal and liver function tests
Second Year and Beyond
- At least annually:
- All tests listed above
Additional Vitamin Monitoring
For All RNY Patients
- Zinc: Check serum/plasma zinc levels at least annually 1
- Copper: Should be monitored alongside zinc supplementation to prevent deficiency 2
For Patients with Specific Symptoms
- Vitamin A: Check if patient reports steatorrhea, night blindness, or protein malnutrition 1
- Vitamin E: Check if unexplained anemia or neuropathy develops 1
- Thiamine (B1): Consider checking in patients with persistent vomiting, rapid weight loss, or neurological symptoms 2
Monitoring Considerations
Target Levels
- Vitamin D: Serum 25-hydroxyvitamin D levels ≥75 nmol/L are considered sufficient 1
- Ferritin: Target level >50 ng/mL 2
Special Monitoring Situations
- Pregnancy: Monthly monitoring is essential during pregnancy with increased attention to folate (800-1000 μg daily) 2
- Patients with malabsorptive symptoms: May require more frequent monitoring and higher supplementation doses 1
Clinical Pearls
- Vitamin deficiencies after RYGB are more common than previously appreciated and can involve both fat-soluble and water-soluble vitamins 3
- Black patients and women may be at higher risk for certain vitamin deficiencies and may require more vigilant monitoring 3
- Standard multivitamin supplements containing approximately 100% RDA are often insufficient after RYGB; specialized bariatric formulations with higher doses of key nutrients show better outcomes in preventing deficiencies 4
- Even with optimized vitamin D levels and recommended calcium intake, fractional calcium absorption decreases dramatically after RYGB 5
- Megaloblastic and macrocytic anemia associated with vitamin B12 deficiency can be masked by concurrent folic acid supplementation 1
By following this structured monitoring approach, clinicians can identify and address nutritional deficiencies early, preventing serious complications that affect morbidity, mortality, and quality of life in post-bariatric surgery patients.