What is Vitamin A
Vitamin A itself comes in many forms, but the three most significant forms are retinol, retinal, and retinoic acid. Despite being very similar in name, the three forms each play different roles in the body. Retinol, the animal form of Vitamin A, is the most common supplement form. It can be converted in the body to retinal, which is important for eye health, and retinoic acid, which is great for the skin, bones, and teeth.
Retinol is the "food form" of Vitamin A, and the body can easily convert it to retinal and retinoic acid as needed. Food sources of retinol, the active form of Vitamin A, include animal products like eggs, liver, beef, and dairy products. Beta-carotene and the other carotenoids, which can be converted to Vitamin A in the body, are found in orange fruits and vegetables.
Retinal is the form of Vitamin A that plays a vital role in eye health. Retinal regulates the conversion of light into impulses that allow us to see. Because of this important function of retinal, Vitamin A deficiency is often characterized by vision impairment and night blindness.
Retinoic acid, on the other hand, is important for healthy skin, bones, and teeth. It can prevent keratinization, or the drying out and hardening of skin . For this reason, Vitamin A is commonly used as a treatment in disorders of skin keratinization. Retinoic acid is also essential for the healthy growth of bones and teeth. Other important roles of Vitamin A include immune support, reproductive health, menstrual regulation in women, and cellular growth and metabolism.
Beta-carotene is the precursor of Vitamin A. It is a pigment that is highly concentrated in orange vegetables like carrots and sweet potatoes. Beta-carotene possesses antioxidant properties, meaning that it can be used to destroy harmful free radical molecules that cause cellular damage. For this reason, beta-carotene and other antioxidants are being studied for their applications in cancer prevention.
Vitamin A Deficiency
Vitamin A deficiency is characterized by stunted growth, impaired vision, night blindness and increased susceptibility to disease. In extreme cases, complete blindness can occur. Deficiency also contributes to increased mortality and impaired lactation among pregnant women and mothers.
Vitamin A supplements can come in a variety of forms. Most supplements are synthetic or animal-based retinol. However, you can purchase carotenoid supplements too. Because Vitamin A is a fat-soluble vitamin, it needs to be taken with a small amount of fat to be properly absorbed and utilized by the body. Vitamin A supplements should be purchased as gel caps or drops that contain an oil. The most commonly-used oils in vitamin supplements are soybean and sunflower oil, so try to purchase a Vitamin A supplement that is oil-based for maximum effectiveness. However, do not exceed 10,000 IU of Vitamin A per day.
The recommended amount of retinol needed to prevent Vitamin A deficiency is 900 micrograms for men and 700 micrograms for women. Many supplement manufacturers report Vitamin A amounts in International Units (IU). Men should aim for 3,000 IU per day, and women should aim for 2,333 IU per day of Vitamin A in any of its forms .
There are some important things you should know before you take a Vitamin A supplement. The Tolerable Upper Limit of Vitamin A is 10,000 IU. This means that you should take no more than 10,000 IU per day. When you consume more than the Tolerable Upper Limit of any nutrient, harmful side effects may occur .