Vitamin A and zinc status in patients on maintenance haemodialysis.

The objective of this study was to assess the vitamin A and zinc serum levels in patients undergoing haemodialysis (HD) in the city of Recife, in the north-eastern region of Brazil. The study comprised 55 patients and 28 healthy controls. The retinol and zinc serum concentrations were analysed by using high-performance liquid chromatography (HPLC) and atomic absorption spectrophotometry, respectively. The mean retinol serum concentration in patients (2.50 +/- 0.86 micromol/L) was significantly greater (P < 0.001) than that found in controls (1.26 +/- 0.86 micromol/L). The retinol serum levels in the patients were as follows: 47.3% of the patients had elevated levels (>/= 2.24 and < 3.50 micromol/L); 16.4% of the patients had serum levels >/= 3.50 micromol/L, which indicated hypervitaminosis; and 9.1% of the patients had serum levels below the normal range (<1.05 micromol/L), a rate that among the controls was 42.9% (P < 0.01). In regard to zinc, the serum levels found in the patients (10.59 +/- 3.12 micromol/L) were similar to those found in the controls (11.43 +/- 2.82 micromol/L) (P > 0.05). Although 49.1% of the patients and 35.7% of the controls were classified as deficient in zinc, this difference was not statistically significant (P > 0.05). The results identified a high prevalence of zinc deficiency in the groups studied, and point to a trend towards more elevated retinol serum levels in patients undergoing dialysis as compared with those in healthy controls.