Most of the baby’s hair is thinner after birth, and can appear to varying degrees of yellowing phenomenon, generally do not worry, with the growth of hair will gradually become black, but if the child is originally black hair gradually become yellow, it is necessary to find the cause of yellow hair, the following list of several common causes of yellow hair. 1, malnutrition yellow hair: mainly due to moderate to severe malnutrition caused. Should pay attention to the deployment of diet, improve the nutritional status of the body. Eggs, lean meat, soybeans, peanuts, walnuts, black sesame contains a large amount of animal protein and vegetable protein, but also contains the main components of hair cystine and cysteine, is the best food for hair care. 2, functional yellow hair: the main reason is mental trauma, fatigue, seasonal endocrine disorders, drugs and chemicals stimulation and other causes of the body melanogen and melanocyte production disorders. This kind of yellow hair can eat more sea fish, black sesame, alfalfa vegetables, etc.. Black sesame can biochemical melanogen; the active ingredients in alfalfa can replicate melanocytes and have the function of regenerating melanin. 3, pathogenic yellow hair: because of certain diseases, such as iron deficiency anemia or a major illness, can make the hair from black to yellow. This condition can eat more black beans, walnuts, cumin, etc.. Black beans contain melanin-producing substances, which have the effect of promoting melanin; aniseed ether in cumin helps to transform melaninogen into melanocytes, thus making the hair black and shiny. 4, copper deficiency yellow hair: the lack of an important copper-containing “tyrosinase” in the process of generating melanin in the hair. The lack of copper in the body will affect the activity of this enzyme, making the hair yellow. Foods rich in copper include animal liver, tomatoes, potatoes, celery, fruits, etc. If your baby’s hair has only recently turned yellow, it is advisable to observe the diet and gastrointestinal tract to rule out disease as the cause, if you are not sure, you can go to the hospital for further examination.