The fat-soluble, Vitamin A is important for: Antioxidant production- If low levels of Vitamin A, different levels are needed throughout the day and the rhythm can be altered resulting in reduced cognitive performance due to catalase, GPx, Glutathione and BDNF. Cell differentiation- Vitamin A helps cells to mature and develop certain denite characteristics and properties. When cells divide and multiply, vitamin A helps guide them in the direction they need to go. Normal circadian rhythm- If Vitamin A levels are lowered it can cause circadian dysrhythmia that can bring cognitive dysfunction and mood disorders. If levels are high, it can cause mental confusion. Eye and Skin Health- Vitamin A is needed to keep our eyes and skin healthy and to protect them from UV damage. Vitamin A helps maintain a crystal-clear outer window, the cornea, without enough it can cloud over. The retina in the back of the eye, vitamin A is part of the pigment that reacts chemically when struck by light and helps create nerve impulse that goes to the brain and creates a visual message. Vitamin A can help with night blindness. Without proper vitamin A, your eyes recover slower after bright light ashes at night, or if unable to see in dim light. It can help with hyperkeratosis and acne. A deciency in vitamin A can cause night blindness if a severe deciency it can also cause blindness. Higher levels can cause hair loss. Retinoic acid- Is important for seasonal rhythms. Growth and development- A deciency can lead to growth delays. Reproduction- A deciency can cause infertility. Immune Health- Vitamin A is important to keep your immune system healthy, as well as your gut immune system. Vitamin A helps maintain the surface of the skin, the mucous membranes lining the nose and throat and the tissues lining the intestines, bladder, and other internal cavities. These benets help boost immunity since mucous membranes help prevent invasion by bacteria and viruses. If decient it can worsen an infectious disease or cause thyroid problems. If levels are high, it can cause liver damage. Cautions- Avoid taking more than 25,000 IU of Beta-carotene as supplements. Can cause lung cancer in smokers taking 50,000 IU in supplement form. High levels of retinol have been associated with cancer and heart disease. It is advised to monitor your retinol levels by a trained provider.