Does the human hair still need nutrition after it grows?

Hair is a kind of hair, which is a keratinized rod-like structure in which the epithelial tissue of epidermis grows in the depth. Its growth is periodic, and it is called a cycle from growth to shedding. Each cycle is divided into growth period, decline period and end period. The growth period of human hair is long, up to 6 years. The recession period is weeks to months; The final stage will take several months. 80% of normal people's hair is in the growing period. It goes without saying that human hair needs constant nutrition after it grows out. The main reason is that hair, like all tissues in our body, is constantly undergoing metabolism. According to experts' research, hair needs not only nutrition, but also many aspects of nutrition: ① 98% of the dry weight of hair is protein, so it is very important to supply adequate protein for human health. Insist on eating more foods containing vitamin A, and your hair will remain soft and shiny. Because hair is an appendage of the skin, their health is closely related. With enough vitamin A, the cells in the lower layer of the skin will not easily die off, sebaceous glands and pores will not be blocked, so that the oil secreted by sebaceous glands can reach the skin surface and moisturize the skin and hair. The most important nutrient in hair is oil. Nutritionists call unsaturated fatty acids in oil "cosmetic acids". "Beauty acid" is the most abundant in vegetable oil, so eating some vegetable oil often is of great benefit to the health and beauty of hair.