Micronutrient status after Roux-en-Y gastric bypass in patients receiving intensive postoperative nutrition...

To evaluate whether an intensive, multi-stage, dietitian-led nutrition education program was associated with changes in micronutrient deficiencies (MNDs) over the first postoperative year following Roux-en-Y gastric bypass (RYGB).

This retrospective cohort study was conducted at a tertiary academic Obesity and Metabolic Syndrome Center. Adults aged 19-66 years who underwent RYGB between September 2018 and January 2019 and completed scheduled postoperative nutrition visits at 1, 2, 3, 6, 9, and 12 months were included. The intervention consisted of structured nutrition education emphasizing multivitamin (MV) supplementation, postoperative diet progression, and reinforcement of nutrition recommendations. Changes in serum vitamin D, vitamin B₁₂, iron, and folate status, and body mass index (BMI) from baseline to 12 months were assessed using paired statistical comparisons and logistic regression.

At 12 months, patients showed a 31% reduction in BMI. Deficiencies in vitamin D and vitamin B12 significantly decreased by 68% and 61% (p < 0.001; p < 0.05, respectively). At 12 months, iron-status indices demonstrated mixed findings: iron MND decreased by 8.2 percentage points, although this change did not reach statistical significance (p = 0.057), while ferritin levels remained largely unchanged. In contrast, iron-related hematologic indicators (hemoglobin and hematocrit) showed non-significant 4.9, (p = 0.302), and 3.9, (p = 0.289) percentage point increases, respectively. Similarly, folic acid MND also showed a non-significant (p = 0.424) 4.7 percentage points decrease at 12 months.

Intensive, dietitian-led postoperative nutrition education was associated with improvements in vitamin D and B₁₂ levels and a lower incidence of MND after RYGB. These data warrant larger, more robust studies to examine further whether intensive, structured education can provide an effective, durable, and low-cost approach to supporting postoperative nutritional status in patients undergoing RYGB.