The effect of Roux-en-Y gastric bypass on zinc nutritional status

Researchers have found that zinc nutritional status in obese and diabetic subjects is altered: low zinc concentrations in plasma and erythrocytes, with high urinary zinc excretion, were observed. This study evaluated the effect of Roux-en-Y gastric bypass (RYGBP) on plasma, erythrocyte and urinary zinc concentration.

22 morbidly obese patients were studied before and 6 months after RYGBP. Fasting blood sample and 24-hour urine were collected in the pre- and postoperative phases. A software analyzed the diet information from 3-day food records after RYGBP. Zinc nutritional status was evaluated by determination of the concentration of this mineral in plasma and erythrocytes, and the urinary excretion of zinc / 24 hours by atomic absorption spectrophotometry.

The diets consumed by the patients had adequate average concentrations of zinc. Zinc concentration in plasma, erythrocytes and urine were within the values of normality before RYGBP, with mean values of 93.25 +/- 19.34 microg/dL, 43.85 +/- 7.76 microg Zn/gHb and 583.05 +/- 359.30 microg Zn/24 hours, respectively. At 6 months after RYGBP, there was a change in these parameters to 69.82 +/- 10.95 microg/dL, 51.80 +/- 6.92 microg Zn/gHb, 535.29 +/- 216.40 microg Zn/24 hours in the concentration of plasma, erythrocyte and urinary zinc.

These results suggest that RYGBP promoted, besides change in body composition, an alteration in the zinc plasma and erythrocytes concentrations which in the medium and long term, could cause problems for these patients.