And yet recent immigrants' children, who were born in poor peasant areas with likely poor nutrition, tend to do well -- PROVIDED they came from East Asia.
[ quick and brief ] recalling an explanation of why something changed in people suddenly - one day - in 1800’s - THE day ELECTRICITY GENERATORS were turned ON in NewYorkCity.
Same thing gradually worked its way as ELECTRICITY was added to more and more areas.
Reason: Prior to electricity, people heated with wood, wood ashes FERTILIZED their food/gardens. ERGO all the GOOD NUTRIENTS they got that way - had stopped when that stopped with the using of electricity.
(This may take exception to immigrants having poorer nutrition.)