Vitamin therapy in cystic fibrosis--a review and rationale.

Vitamin supplements are routinely prescribed in cystic fibrosis, but published recommendations vary widely and there is little consistency in clinical practice. A review of the literature confirms that, while supplementation of the water-soluble vitamins (including B12 and folate) is unnecessary in uncomplicated cystic fibrosis, deficiency of the fat-soluble vitamins can lead to clinical problems. Supplements of these vitamins should be ensured for all patients with cystic fibrosis, while sparing them the unnecessary inconvenience of taking other vitamin supplements except where these are specifically indicated.