Vitamin A supplementation according to zinc status on oxidative stress levels in cardiac surgery patients.

ABSTRACT

INTRODUCTION: it is widely reported that oxidative stress increases in patients undergoing cardiovascular surgery and causes negative outcomes, such as reduced immunological responses and postoperative complications. In this context, vitamin A and zinc serves an important function in the immunological system because it plays a role in fighting oxidative stress. OBJECTIVES: to evaluate the effect of vitamin A supplementation on oxidative stress levels in cardiac surgery patients based on zinc nutritional status. METHODS: a control group (G1) and a vitamin A intervention group (G2- 5,000 IU of vitamin A daily) were subdivided based on their zinc nutritional status. The patients' serum concentrations of retinol, ß-carotene, zinc and malondialdehyde were assessed before surgery (T0), on the 3rd (T1) and 21st postoperative day (T2). RESULTS: in the individuals with adequate zinc concentrations, the retinol concentrations were significantly higher in G2 than in G1 at T1 and T2. In G2, the ß-carotene concentrations were significantly higher in individuals with adequate zinc concentrations compared to those who had inadequate concentrations at T1 (p = 0.024) and T2 (p = 0.043). After surgery, malondialdehyde levels were significantly higher in individuals who had inadequate zinc concentrations, compared to those who had adequate zinc concentrations. Analyzing the clinical evolution, operative mortality, hospitalization time and length of stay in Intensive Care Unit (ICU) were lower in G2. CONCLUSION: vitamin A has contributed to the reduction of oxidative stress, particularly in patients with adequate zinc concentrations and, this way, may help decrease the risk of postoperative complications.