Where do you pull "40 point IQ difference" from? The gap between these impoverished kids and normal is only 20 points. And that is easily explainable with nutrition, stimulation, and education.
Independently, the estimated difference between average IQ in the mid-30s and today is 20 points. See http://en.wikipedia.org/wiki/Flynn_effect for verification. In that time period the main things that have changed are nutrition, stimulation and education.
So there you have it. Two unrelated analyses of completely different things finding that nutrition, stimulation and education can explain 20 point IQ differences between otherwise similar populations.
But not so important that they would have a 40 point IQ difference. If it is, show me the studies confirming that.