Lipid Peroxidation and Antioxidant Status in Adults Receiving Lipid‐Based Home Parenteral Nutrition

Abstract

Infusion of lipid emulsions rich in polyunsaturated fatty acids (PUFAs) may increase lipid peroxidation, which is counteracted mainly by superoxide dismutase (SOD) (a zinc‐, copper‐, and manganese‐dependent enzyme), selenium‐dependent glutathione peroxidase (Se‐GSHPx), and alpha‐tocopherol. Objective: We investigated lipid peroxidation and antioxidant status in patients receiving home parenteral nutrition (HPN) providing variable amounts of a lipid emulsion rich in PUFAs, and alpha‐tocopherol, zinc, copper, and manganese as recommended by the American Medical Association, and no selenium. Design: Serum malondialdehyde, plasma alpha‐tocopherol, selenium, Se‐GSHPx, PUFAs, and red blood cell Se‐GSHPx and SOD were evaluated in 12 patients and in 25 healthy control subjects. Malondialdehyde was also assessed in a group of 40 healthy control subjects. Results: Patients had significantly higher concentrations of malondialdehyde and SOD and lower alpha‐tocopherol concentrations and selenium nutritional status. Linear regression analysis showed that malondialdehyde was associated with the daily PUFA load (r = 0.69, P < 0.03) and with plasma alpha‐tocopherol (r = ‐0.59, P < 0.05), but stepwise multiple regression analysis confirmed only the association between malondialdehyde and alpha‐tocopherol; plasma alpha‐tocopherol was associated with the daily PUFA load (r = ‐0.65, P < 0.04) and with the duration of HPN (r = ‐0.74, P < 0.02). Conclusions: In HPN patients, the peroxidative stress due to lipid emulsions rich in PUFAs is counteracted primarily by alpha‐tocopherol. The dosages of alpha‐tocopherol, zinc, copper, and manganese recommended by the American Medical Association appear sufficient to sustain SOD activity but inadequate to maintain alpha‐tocopherol nutritional status. HPN formulations should be supplemented with selenium.