Vitamin A is an essential element in the body, and long-term deficiency can easily cause eye and skin problems. Vitamin A deficiency may be simply due to a relatively low dietary intake, or it may be related to some digestive dysfunction. Vitamin A is usually derived from meat foods and dark vegetables. Long-term non-consumption of such foods, or relatively low intake, can easily lead to vitamin A deficiency. In addition, it is difficult for vitamin A to enter the fetus through the placenta, so the vitamin A in the liver and serum of the newborn will be significantly lower than that of the mother, which can easily lead to vitamin A deficiency if it is not supplemented in time at birth. Vitamin A is a fat-soluble vitamin, which has to go through some complicated procedures in digestion and absorption. Reduced secretion of bile and pancreatic enzymes, or suffering from digestive system diseases, can lead to impaired absorption of vitamin A and cause vitamin A deficiency in the body. In addition, liver dysfunction can also affect the storage of vitamin A in the body, resulting in vitamin A deficiency.