Alex is a big guy: 6 ft 4 inches, 273 lbs.
On 10,000 units per day of vitamin D in gelcap form, his 25-hydroxy vitamin D level was 38.4 ng/ml. One year earlier, his 25-hydroxy vitamin D level, prior to any vitamin D supplementation was 9.8 ng/ml.
According to the latest assessment offered by the Institute of Medicine (IOM):
Vitamin D need for a 13-month old infant: 600 units per day
Vitamin D need for a 6 ft 4 in, 273 lb male: 600 units per day
I paint this picture to highlight some of the absurdity built into the smug assumptions of the IOM's report. It would be like trying to fit a large, full-grown man into the diapers of a 13-month old. Few nutrients or hormones (in fact, I can't think of a single one) are required in similar quantity by an infant or toddler and a full grown adult. However, according to the IOM's logic, their vitamin D needs are identical, regardless of age, body size, skin color, genetics, etc. One size fits all.
Just as the original RDA assessment by the Institute of Medicine kept thinking about vitamin D somewhere in the Stone Age, so does this most recent assessment.