Your body uses vitamins, minerals and other nutrients to carry out a multitude of functions. Vitamin A is a general term used to describe a number of related compounds. It is a nutrient your body needs. You get vitamin A from your diet. Protein-rich foods, such as meat, eggs, milk, cheese, liver and certain fish, like cod and halibut are good sources of vitamin A.
Functions
Vitamin A is needed to maintain healthy skin, teeth, mucous membranes, skeletal and soft tissues. Retinol is a more active form of vitamin A. It plays an important role in vision by producing pigments in the retina, the light-sensitive inner surface of the eye. Retinol is found in animal livers and whole milk. Vitamin A is also needed for proper bone growth, reproduction, immunity and cell division.
Immunity
Vitamin A is known as an anti-infective vitamin because it is needed for the healthy functioning of your immune system. It promotes healthy linings of the respiratory, urinary and intestinal tract. This lining protects against foreign invaders, such as bacteria, by making it difficult to penetrate. If this barrier weakens or breaks down, it becomes easier for bacteria to enter, where they can cause an infection. Mucous membranes created by vitamin A also help protect against viruses and bacteria.
Vision
The retina is at the back of your eye. Your retina senses light passing through the lens and sense a signal to your brain. Retinol is transported to the retina and accumulates. It then undergoes a chemical change and binds to a protein known as opsin where it is stored as visual pigment. When this process is complete, your brain is able to interpret the degree of light passing through the eye. Inadequate retinol results in night blindness, or low visual acuity at night.
Beta-Carotene
Beta-carotene is a form of vitamin A found in plants. Colorful fruits and vegetables are rich sources of beta-carotene. It is an antioxidant that helps protect your cells and tissues from free radical damage, highly charged, unpaired molecules that result from energy uptake and can cause damage as they seek out electrons to pair up with. According to Medline Plus, free radicals are associated with degenerative diseases that play a role in the aging process.
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