Antioxidant relationship between selenium-dependent glutathione peroxidase and tocopherol

Area of Science:

• Biochemistry
• Nutritional Science
• Pediatric Medicine

Background:

• Glutathione peroxidase (GPx) is a selenium-dependent enzyme crucial for antioxidant defense.
• Tocopherol (vitamin E) also acts as an antioxidant.
• These nutrients may interact and compensate for each other's deficiencies.

Purpose of the Study:

• To investigate the interaction between selenium, glutathione peroxidase, and tocopherol in premature infants.
• To determine the role of dietary polyunsaturated fatty acids (PUFA) and iron in selenium and tocopherol deficiency-related hemolysis.
• To establish optimal nutritional strategies for preventing peroxidation in vulnerable infants.

Main Methods:

• Observational study of low-birth-weight premature infants fed specific formulas.
• Analysis of infant formulas for polyunsaturated fatty acid (PUFA) content, iron, selenium, and tocopherol levels.
• Clinical assessment for hemolysis and correlation with nutrient intake and status.

Main Results:

• Infants fed selenium-poor formulas rich in PUFA (>35% fat) and supplemented with iron developed severe hemolysis.
• This hemolysis was linked to erythrocyte phosphatidyl ethanolamine loss.
• Increased tocopherol supplementation prevented the clinical signs of relative tocopherol and absolute selenium-glutathione peroxidase deficiency.
• Selenium-poor cow's milk preparations with 12-15% PUFA, trace iron, and 12-15 mg/L tocopherol prevented peroxidation.

Conclusions:

• A delicate balance of selenium, glutathione peroxidase, and tocopherol is essential for premature infants.
• Formulas high in PUFA require adequate tocopherol and selenium to prevent oxidative stress and hemolysis.
• Carefully formulated cow's milk preparations can support adequate nutrition without increasing peroxidation risk.