Baby just born hair black later how to become yellow, mainly because the human body lacks trace elements, will lead to hair yellow, after excluding nutritional factors, there may be pathological reasons (such as thyroid function decline, anemia). As iron, zinc, copper and other trace elements are the basic substances of melanin metabolism in human tissue cells and skin hair, if the lack of minerals, it will lead to premature yellowing of hair. Black beans, black rice, black fungus, black sesame, etc. are rich in minerals, in the baby’s diet should pay attention to nutritional balance. You can eat more fruits and vegetables to supplement the trace elements needed by the body. Some pathological reasons cannot be ruled out, such as decreased thyroid function, anemia, phenylketonuria, etc. These will lead to a decrease in melanin content in the body, resulting in withered hair. Children with the above conditions are recommended to go to a regular hospital for a comprehensive examination to determine the cause, and then targeted treatment.