If a person's hair is very thick and shiny black, it means that this person's kidney is very good, and such people generally live longer. In fact, in Chinese medicine, the kidney is the whole source of human energy. The kidney is in charge of many organs and some parts of the human body. Among them, most of the head is managed by the kidney. If a person's kidney function is poor, then this person will lose hair, and the shine is very rare and dry. If everyone wants to have thick hair, then in daily life, everyone needs to maintain their kidney function and pay attention to their eating habits.