Vitamin E supplementation in people with cystic fibrosis.

Systematic review of four small parallel-group trials in people with cystic fibrosis, mostly children and adolescents, including participants with mild lung disease and some receiving pancreatic enzyme replacement therapy. Studies were conducted in the United Kingdom, the United States, and Canada, with inconsistent reporting of pancreatic sufficiency and other baseline characteristics.

Vitamin E was given orally in small randomized trials using either water-miscible or fat-soluble formulations, typically at 10 mg/kg/day, with one study using RRR alpha-tocopherol 600 IU/day for participants under 20 kg and 1200 IU/day for those over 20 kg. Durations were short, ranging from about 1 month to 6 months, and comparators included no supplementation or placebo.

Vitamin E supplementation improved serum vitamin E levels in people with cystic fibrosis, but there was no evidence available for deficiency-related clinical outcomes such as lung function or quality of life. Reported effects on serum vitamin E were positive across short follow-up periods, including MD 13.46 (95% CI 9.03 to 17.89) and MD 17.66 (95% CI 10.59 to 24.74) at up to 1 month in one trial, MD 11.61 (95% CI 4.77 to 18.45) at up to 3 months and MD 19.74 (95% CI 13.48 to 26.00) at up to 6 months in another, and MD 13.59 (95% CI 9.52 to 17.66) at up to 1 month in a third. One trial found no clear effect at up to 3 months (MD 6.40, 95% CI -1.45 to 14.25), and the review concluded that larger, better-designed trials are needed to define optimal dosing and clinical benefit.

The evidence base was very small and at risk of bias, with short follow-up and limited reporting of allocation, blinding, and completeness of data. Clinical outcomes beyond vitamin E status were not reported, and baseline pancreatic status, co-interventions, and participant characteristics were inconsistently described, limiting generalizability and interpretation.