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With Comments from John La Puma, MD, FACP
September 2001; Volume 4; 107-108
Source: Renner S, et al. Effects of beta-carotene supplementation for six months on clinical and laboratory parameters in patients with cystic fibrosis. Thorax 2001;56:48-52.
Patients with cystic fibrosis (CF) have significantly decreased plasma concentrations of nutrient antioxidant vitamins, especially of beta-carotene, which is thought to result from fat malabsorption and chronic pulmonary inflammation. The aim of this double-blind, placebo-controlled study was to investigate the effect of oral beta-carotene supplementation for six months on clinical parameters.
Twenty-four CF patients were randomized to receive 1 mg/kg/d beta-carotene (maximum 50 mg/d) for three months (high-dose supplementation) and 10 mg/d for a further three months (low-dose supplementation) or placebo. At monthly follow-up visits, the plasma beta-carotene concentration, total anti-oxidant capacity, malondialdehyde (MDA) as a marker of lipid peroxidation, and clinical parameters (Shwachmann-Kulczycki score, body mass index [BMI], height, and lung function [FEV1]) were assessed. The number of pulmonary exacerbations requiring antibiotic treatment three months before and during the study were evaluated.
Plasma concentration of beta-carotene increased significantly to the normal range during the three months of high-dose supplementation (baseline 0.08 [0.04] micromol/l to 0.56 [0.38] micromol/l; P < 0.001), but decreased to 0.32 (0.19) micromol/l in the period of low-dose supplementation. Initially raised plasma levels of MDA fell to normal levels and the total antioxidant capacity showed a non-significant trend toward improvement during high-dose supplementation. Antibiotic treatment decreased significantly in the supplementation group from 14.5 (14.9) days/patient during the three months before the study to 9.8 (10.3) days/patient during high-dose supplementation (P = 0.0368) and to 10.5 (9.9) days/patient during low-dose supplementation, but increased in the placebo group. The Shwachmann-Kulczycki score, lung function, and BMI did not show any changes in either of the treatment groups. No adverse events were observed during the study period.
The authors conclude that oral beta-carotene supplementation in a dose of 1 mg/kg/d was effective only in normalizing the plasma concentration of beta-carotene and resulted in a decrease in pulmonary exacerbations. These data suggest that patients with CF may benefit clinically from supplementation with beta-carotene and further studies are warranted.
Beta-carotene has been tested for effectiveness and safety in a number of medical conditions, most famously in the prevention of coronary artery disease. In that study, and in another study, an increase in the incidence of lung cancer was discovered in smokers after 5-8 years of supplementation. Beta-carotene as a supplement is not recommended for routine use and the beta-carotene arm of the Women’s Health Initiative has been discontinued.
For patients with CF, however, the benefits may outweigh the risks. In this well-designed randomized, double-blind, placebo-controlled study from Vienna, Austria, CF patients started with significantly lower mean plasma beta-carotene concentrations, had six months of supplementation, and markedly reduced their dependence on antibiotics to treat an acute pulmonary exacerbation. No significant change in FEV1, percent predicted, and total antioxidative capacity was noted between the groups.
The baseline low levels of beta-carotene are postulated to result from malabsorption, and chronic pulmonary inflammation, which perhaps chews up antioxidants.
The authors advise caution in interpretation, as the number of patients is small. However, for this select group of patients with progressive lung disease that invariably results in death, these data should be strongly considered.
Consider beta-carotene supplements in patients with cystic fibrosis in a dose of 1 mg/kg/d with a clear understanding in the informed consent process of the known risks and benefits.