Perhaps I was unclear. I think they should have done the controlled experiment with university staff or students as subjects. If the experiment was really completely harmless, there's no reason not to. If they wanted to study the effects on growing children, they should have used ordinary schoolchildren whose parents consented.

As science, this was complete crap totally apart from the awful ethics. Many developmentally disabled people suffer from chromosomal abnormalities that lead to non-trivial physiological differences between them and the rest of the population, including metabolic and cardiac differences. That makes it extremely difficult to infer anything about effects on the general population from studies done on a small group of developmentally disabled people and that's why people with chromosomal abnormalities are often excluded from most research protocols. I think that you'd know all of this if you were familiar with science.