Study design (if review, criteria of inclusion for studies)
Single centre randomized controlled trial
Participants
Austria. 24 people with CF; 6.7 - 27.7 years of age (18 females, 6 males) diagnosed by sweat test taking regular vitamin supplements and pancreatic enzymes.
Interventions
Dose/frequency/duration: 1 mg/kg/day (max 50 mg/day) for 3 months followed by 10 mg/day for 3 months taken once per day. Control: placebo. Intervention: β-carotene.
Outcome measures
Pulmonary exacerbations and adverse events were also recorded. Lung function (FEV1 % predicted), plasma β-carotene status and BMI measured at 0 and 6 months.
Main results
The 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 towards 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.
Authors' conclusions
Oral beta-carotene supplementation in a dose of 1 mg/kg/day only was effective in normalising 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.