 Ursodeoxycholic acid, a bile salt, has been used, however there is insufficient data to show if it is effective.It is uncertain whether vitamin A or beta-carotene supplementation have any effect on eye and skin problems caused by vitamin A deficiency.There is no strong evidence that people with cystic fibrosis can prevent osteoporosis by increasing their intake of vitamin D.

For people with vitamin E deficiency and cystic fibrosis, there is evidence that vitamin E supplementation may improve vitamin E levels, although it is still uncertain what effect supplementation has on vitamin E‐specific deficiency disorders or on lung function.