"The mean total vitamin D intake during pregnancy was 548 IU/d. By 3 years of age, 186 children (16%) had recurrent wheeze. Compared with mothers in the lowest quartile of daily intake (median, 356 IU), those in the highest quartile (724 IU) had a lower risk of having a child with recurrent wheeze (odds ratio, 0.39; 95% confidence interval, 0.25-0.62). "
"In a randomized controlled trial conducted with postmenopausal African American women living in Long Island, New York, those taking 800 IU/d of vitamin D had a 60% reduction in the incidence of seasonal influenza or common cold. However, those taking 2,000 IU/d had a 90% reduction.53 "