Historically, 400 IU (10 ug) of vitamin D was recommended for better health because it closely approximated the amount of vitamin D in a teaspoonful of cod liver oil. However, 800 to 1,000 IU is ...
For every 100 IU of vitamin D ingested the blood level of 25-hydroxyvitamin D, the measure vitamin D status, increases by 1 ng/ml. It is estimated that children need at least 400-1000 IU of ...