The main causes of yellowing hair are: low thyroid function; high malnutrition; severe iron deficiency anemia and major illnesses, etc., which lead to the reduction of melanin in the organism, making the basic substance of black hair lacking and black hair gradually turning yellowish brown or yellowish. In addition, frequent perming, shampooing with alkaline water or washing powder will also make the hair damaged and yellow. What are the main causes of yellowish hair? 1, malnutrition yellow hair: mainly caused by a high degree of malnutrition, 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 component of hair cystine and cysteine, is the best food for hair care. 2, acidic body yellow hair: with the increase in acidic toxins in the blood, but also with overwork and over-eating sweets, fat-related. Should eat more kelp, fish, fresh milk, beans, mushrooms, etc.. In addition, more fresh vegetables, fruits, such as celery, rape, spinach, cabbage, citrus, etc. is conducive to neutralize acidic toxins in the body and improve the yellow state. 3, 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, so that the hair becomes yellow. Copper-rich foods are animal liver, tomatoes, potatoes, celery, fruit, etc. 4, radiation yellow hair: long-term exposure to radiation, such as computer, radar and X-ray work and hair yellowing, should pay attention to the supplement rich in vitamin A food, such as pig liver, egg yolk, milk, carrots, etc.; eat more radiation-resistant food, such as nori, high protein food and drink more green tea. 5, 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 to eat more sea fish, black sesame, alfalfa vegetables. The active ingredients in alfalfa can replicate melanocytes and have the function of regenerating melanin; black sesame can biochemical melanogen; niacin in sea fish can expand capillaries, enhance microcirculation, make blood and Qi flow smoothly, eliminate melanogenesis disorder, make hair dispel yellow and healthy. 6, pathogenic yellow hair: because of certain diseases, such as iron deficiency anemia and the first recovery from a serious illness, can make the hair from black to yellow. This case should eat more black beans, walnuts, cumin, etc.. Black beans contain melanin-producing substances, which have a melanin-promoting effect. The anisole in cumin helps to transform melaninogen into melanocytes, thus making the hair black and shiny.