The argument I've heard is that the other nutriments needs (vitamins, minerals, etc) don't scale as much with height. So even a very short person would have a vitamins/mineral deficit on less than 1200KCal per day.
How true is it? I don't know. But even then I don't see why they couldn't take multivitamins.
How true is it? I don't know. But even then I don't see why they couldn't take multivitamins.