Effects of long-term oral beta-carotene supplementation on lipid peroxidation in patients with cystic fibrosis.

The aim of this study was to determine the efficacy of oral β-carotene supplementation for the correction of an oxidant-antioxidant imbalance in cystic fibrosis (CF). We studied 24 patients with cystic fibrosis and 14 healthy controls. 13 CF-patients were allocated to a CF-supplementation group, which received 1 mg β-carotene/kg BW/d up to a body weight (BW) of 50 kg, patients with a BW greater 50 kg received 50 mg β-carotene/d for 12 weeks. For the following 12 weeks all patients of the CF-supplementation group were treated with 10 mg β-carotene/d. Placebos with starch were applied to 11 CF-patients. Baseline plasma β-carotene concentrations of CF patients (mean ±SD, 0.08 ± 0.04 μmol/l) were significantly lower than those of age-matched controls (0.3±0.1 μmol/l) (p < 0.001). β-carotene concentrations of the CF-supplementation group increased rapidly and reached value of 0.6 μmol/l after 12 weeks of supplementation. Normal values were measured for plasma ascorbate and α-tocopherol. Plasma retinol concentrations were in the lower normal range and did not increase during supplementation. Total antioxidative capacity in plasma of the CF-supplementation group increased after 12 weeks of supplementation at an extent of 12%. Positive influence was indicated by a decrease of plasma malondialdehyde. Thus oral β-carotene supplementation is effective in normalizing status of β-carotene and malondialdehyde in CF patients.