Individualized vitamin A supplementation for patients with cystic fibrosis

Abstract

Background & aims: To determine the vitamin A status and appropriate supplementation dosage of cystic fibrosis (CF) patients who received vitamin A supplementation based on annual serum retinol measurements.

Methods: Vitamin A food intake, supplementation dosage, and serum retinol levels were obtained for 32 CF patients >4 years of age (4.3-27.3 years old) who had pancreatic insufficiency and mild-to-moderate lung disease (percent predicted of forced expiratory volume in 1 s > 40%). These measurements were compared with the dietary reference intake for healthy children and adults (D-A-CH dietary recommendations), US and German CF recommendations, and serum retinol concentrations from National Health and Nutrition Examination Survey (NHANES) data.

Results: Total vitamin A intake from food and supplementation was 315% ± 182% of D-A-CH recommendations, with 65% from supplements. The range of the prescribed vitamin A supplementation dosage was 0-20,000 IU/day (median 5500 IU), and it was consistent with CF recommendations in 28% of participants. A quarter of all patients did not need any vitamin A supplementation. The total vitamin A intake exceeded the recommended upper limit of intake in 69% of subjects. The mean (range) serum retinol was 38.6 μg/dl (22.1-59.1 μg/dl). All subjects had serum retinol levels above 20 μg/dl and below 72 μg/dl (95th percentile of NHANES reference range).

Conclusion: Individualized vitamin A supplementation of 0-20,000 IU/day based on annual serum retinol measurements may prevent deficiency and high serum retinol levels, but it may lead to vitamin A intake above the tolerable upper intake level.

Keywords: Cystic fibrosis; Dietary supplements; D–A–CH recommendations; FEV1%pred; NHANES; National Health and Nutrition Examination Survey; UL; Vitamin A; dietary recommendations from the D–A–CH countries (Germany (D), Austria (A), and Switzerland (CH)); percent predicted of forced expiratory volume in 1 s; upper limit of intake.