primary studies published RCT Single- and multiple-dose-response relationships of beta-carotene in cystic fibrosis. Year: 1995 Date: 1995 Author: Homnick DN Source J Pediatr. 1995 Sep;127(3):491-4. Study design (if review, criteria of inclusion for studies) single- and multiple-dose studies of beta-carotene supplementation in patients with CF Interventions beta-carotene supplementation Outcome measures beta-carotene concentrations, beta-carotene clearance Main results Dose-proportional increases in beta-carotene concentrations were found, although clearance was independent of dose. Authors' conclusions Large doses of beta-carotene were necessary to achieve normal plasma levels. Related topics A, E, K vitamins supplementation Vitamin D supplementation