Okay, they’re just talking about kids with stunted growth in this particular study, but the principle is the same for all kids. Playing with kids–even just a couple of times a week makes a signficant difference in how happy/well adjusted those kids are when they get older. Report from the British Medical Journal here said nutritional supplements had no effect whatsoever.
You know, this is another one of those that falls into the “well, duh” category for me. Guys, it was in 1957 that Harry Harlow did the experiments with baby rhesus monkeys that proved they just wanted to be loved/touched and that even if you just gave them a cloth-covered wire mother, they developed more slowly, but still became more successful adults than babies who had only a wire mother to feed them.
I think we can stop spending money to prove that loving interaction between babies and their caretakers is the most powerful thing we can do to promote their future health.