Good nutrition at an early age has a great effect on your brain. Your brain itself grows enormous while you are in early childhood. This is your golden age.
While researchers intervened in one group with high nutrient and another placebo, the result is quite striking. Their average income differs significantly almost 30 years later.

What makes this research great? Because the researchers have to wait for 20-30 years to get the result of their research. But, the waiting time is precious because this is the only method to prove or disprove their hypothesis.