In April 2016, I discovered that my child in deficient in vitamin D. The blood level of 25-OH vitD at that time was 15.7 ng/mL. After 3 months of vitamin D supplementation with 1000 ui/day, his level went up to 24 ng/mL. The doctor recommended to continue supplementing with 1000 ui/day. In April 2017, the level of 25-OH vitD was 22.3 ng/mL. I started giving him 1500 ui/day and this month I tested him again for 25-OH vitD and the level is 23.2 ng/mL. I suppose due to this condition, the ionic calcium as well went below limits (4.18 mg/dL).
The child is 5 1/2 years old, olive skin and he weighs 19 kg. Which is the dosage you recommend to achieve the optimum level of vitamin D for him? For how long should I follow your recommended dosage?
Thank you for your time.