Intelligent people have more zinc and copper in their hair

Intelligent people have more zinc and copper in their hair. It is a commonly known fact that people of high intelligence have high concentrations of Zine and Copper in their hair. The question is why? Why do very smart or extremely intelligent folks have more Zinc and Copper in their hair follicles? Some say that smart people retain more zinc and copper and that allows their brains to make connections faster or allow electric transfers of nerves, neurons and brain waves.