Vitamin A deficiency is associated with a wide range of diseases, such as night blindness, dry eyes, dry skin, follicular papules, and susceptibility to infections or inflammation of the mucous membranes of the skin and the mucous membranes of the upper respiratory tract. Vitamin A is found mainly in animal liver, as well as in egg yolks, duck egg yolks, milk, fresh leafy green vegetables, and foods such as carrots and corn. Vitamin A is mainly responsible for the formation of the retinal pigment and maintains the structural integrity of the epithelial tissue and promotes growth and development. The human vitamin A requirement is about 80 μg, or 2,600 units, per day. When taking vitamin A supplements, it is important to note that when frying carrots, for example, you should use oil to fry them, because vitamin A is a fat-soluble vitamin, and frying them in oil promotes its absorption and utilization.