Zinc nutritional status of morbidly obese patients before and after Roux-en-Y gastric bypass: A preliminary report

Background: Previous researchers have found that the nutritional zinc status in obese and diabetic subjects is altered: low zinc concentrations in plasma and erythrocytes with high urinary zinc excretion were observed. This study assessed the influence of the Roux-en-Y gastric bypass (RYGBP) on the plasma, erythrocyte and urinary zinc concentrations before the beginning of the mineral supplementation. Methods: 24 morbidly obese patients were studied before and 2 months after RYGBP (the period in which the patients were still not ingesting mineral supplements). Fast blood sample, 24-hour urine, and 3-day food records were collected in the pre- and postoperative phases. Zinc concentration in the samples was analyzed by flame atomic absorption spectrophotometry, and dietary analysis of the food records were performed using the software Virtual Nutri with the inclusion of zinc concentration in the database for regional foods. Results: Pre- and postoperative results were respectively: plasma 68.0 and 66.3 mu g/dL; erythrocytes 36.6 and 43.8 mu g/g Hb; urine 884.7 mu g/24h and 385.9 mu g/24h; and zinc intake 10.5 and 6.7 mg/day. Conclusion: These results suggest that RYGBP changed mainly the zinc erythrocyte and urinary concentrations. As expected, the zinc intake was lower in the postoperative phase, which in the medium and long term, could cause problems for the patients.