Lack of vitamin A harm

Vitamin A deficiency has clinical and functional characterization. For primary vitamin A deficiency, each person's tolerance is different, depending on a range of geographic and epidemiological factors. The clinical manifestations of vitamin A deficiency are mainly symptoms and signs of ocular and visual and other epithelial dysfunction.
Eye and visual performance:
Dry eye is one of the typical clinical features of vitamin A deficiency. According to the specific eye performance, dry eye syndrome can be divided into several periods. The XN phase is the earliest stage, mainly causing night blindness caused by dark adaptation function damage. After the X1A phase, the goblet cells secrete mucus and the conjunctiva is dry. Next, in the X1B phase, the bubble-like Piedular plaque appears on the frontal surface of the conjunctiva. The X2 phase is the stage of disease progression, which is characterized by simple corneal dryness. When the cornea is softened or ulcerated, or both, the liquefaction process is X3. At this time, if the liquefaction surface is insufficient, 1/3 of the cornea area is the X3A phase, and more than 1/3 is the X3B phase. Eye damage caused by corneal softening is called dry eye disease fundus disease, also known as XF phase.
Embryo growth and development abnormalities:
Vitamin A deficiency can damage embryo growth. Experimental animals with severe vitamin A deficiency often undergo embryo resorption, while surviving embryos also have abnormalities in the eyes, lungs, urinary tract and cardiovascular system. When the body is deficient in vitamin A, there is less morphological abnormality, but the function of the lung is abnormal.
Impaired immune function:
Vitamin A deficiency can lead to a decrease in the number of blood lymphocytes, a decrease in natural killer cells, and a decrease in specific antibody responses. When vitamin A is insufficiently ingested, a decrease in the number of white blood cells, a decrease in the weight of lymphoid organs, a loss of T cell function, and a decrease in immunity against immunogenic tumors can be observed. In experimental animals and human experiments, vitamin A deficiency leads to abnormal humoral and cellular immune functions.