Vitamin and Mineral Supplementation Critical After Gastric Bypass

There are fewer micronutrient deficiencies among gastric bypass patients than previously indicated.

Roux-en-Y gastric bypass (RYGB) produces persistent weight loss and prevents type 2 diabetes, hyperlipidemia, hypertension, and obstructive sleep apnea. However, it also decreases absorption of iron, folate, calcium, thiamine, copper, zinc, and vitamins A, D, and B12.

The Clinical Practice Guidelines for the Perioperative Nutritional, Metabolic, and Nonsurgical Support of the Bariatric Patient recommend multivitamin/mineral, calcium citrate, vitamin D, and vitamin B12 supplementation and micronutrient monitoring after gastric bypass surgery.

Recently, a team of researchers from the Mayo Clinic found fewer micronutrient deficiencies among RYGB patients than previously indicated by published research.

A 1991 study found that 64% of patients were adherent to medications after 2 years. A 2014 study found that patients who follow-up with their providers annually are more adherent to medications. This study documents RGYB patients’ self-reported medication adherence at 92%.

The retrospective study enrolled 287 patients undergoing RGYB at the Mayo Clinic between May 1, 2010, and April 30, 2012. Nurses gathered patient-reported medication lists and recorded micronutrient monitoring test results at 6-, 12-, 18-, and 36-month follow-up visits. Providers and patients were most likely to discontinue calcium supplementation because of intolerance or favorable laboratory results.

More patients had inadequate levels of vitamin D than vitamins A or E; however, the researchers recommended that vitamin D supplementation should be increased (eg, 5000 IU daily) in RYGB patients.

Anemia and iron deficiency was less common with a 36-mg daily dose of elemental iron than in previous studies. Iron deficiency was more common in men than women (unlike in the general population), but this may be linked to underappreciation of male patients’ risk.

Vitamin B12 deficiency was an unlikely driver of non-iron anemia because 96% of patients had adequate vitamin B12 levels at 18 to 36 months.

Twice-daily multivitamin/mineral, iron supplementation, and monthly vitamin B12 injections prevented vitamins A, E, and B12 deficiency effectively in gastric bypass patients. Providers should supplement vitamin D and iron aggressively to avoid deficiency.

The near-complete adherence to supplements and minimal micronutrient deficiency in this study shows that patients appear to understand how important supplements are after gastric bypass.