Nutrition Bytes

In 2001 the Food and Nutrition Board (FNB) of the Institute of Medicine, after reviewing the available literature, set the tolerable upper intake level of vitamin A at 3,000 g/day (1). While setting the upper intake level, the FNB chose not to factor into their decision several conflicting studies linking excessive vitamin A consumption with fractures. Since the vitamin A review, however, further studies have continued to solidify the relationship between high vitamin A intake and fracture risk. One such study found that ingestion of a daily amount of vitamin A significantly less than the tolerable upper intake level was associated with doubling the likelihood of a fracture (2). Many other studies like this one draw the same conclusions suggesting prudence in vitamin A consumption and the necessity of lowering the currently accepted tolerable upper intake level.