I read this Successful treatment of reactive airways dysfunction syndrome by high-dose vitamin D https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3196486/ At this stage, the immunological properties of vitamin D were being reported, and we began a trial of high-dose oral vitamin D 2000 IU/day. Vitamin D levels were requested, but her local hospital did not routinely perform this test. As a result, measurement at our hospital was arranged at her next visit. This showed a vitamin D level of 57 nmol/L at eight weeks after commencing the high dose. Scientific data from osteoporosis research shows a rise of 8–10 nmol each month on a vitamin D dose of 1000 IU/day. This would suggest that our patient’s vitamin D level was <25 nmol/L, initially consistent with severe deficiency. History-taking confirmed no ingestion of oily fish and no sunlight exposure or sunbathing for many years. At the start of vitamin D therapy, her symptoms were severe with incessant cough and bronchial hyper-reactivity as described before, which made measurement of formal lung function difficult. Her chest remained clear on physical examination, and she had a C-reactive protein of 0.2 and an immunoglobulin E of 9 kU/L. High-dose vitamin D has been continued and blood levels have remained at 150–200 nmol/L with normal calcium levels. There are no reported adverse effects of regular vitamin D at doses of up to 5000 IU/day. The current recommendation for adults is now 1000 IU/day. There were no side effects of the vitamin D, but oral preparations are known to have a mild laxative effect and increase skin oils that may cause spots. Q: What do you think of that statement ?