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.

To start look at http://www.thewayforwardproject.org/file_uploads/Gen10%20IQ%... for a meta analysis of thousands of studies finding that the IQ difference between growing up in an orphanage and foster care averaging 20 points.

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.

Did you just pull "40 points" out of thin air because there are plenty of studies showing economic causes for smaller differences?

If your nutrition is poor enough you will be dead. It is well established that dead people necessarily have low IQs. Q.E.D.