Vitamin A (Retinol)

Vitamin A

vitamin A

Vitamin A is a fat soluble vitamin– necessary for healthy eyesight, including color vision and night vision. It is also important for healthy teeth and bones, correct functioning of the skin, immune and reproduction systems, cells growth. This vitamin may play a role in the prevention of certain cancers and cataracts.

Vitamin A is a group of vitamins that are also known by many names. The two principal forms of this vitamin are the retinols, such as retinyl acetate (a natural form of the vitamin), and the carotenes, such as beta carotene. Retinol is a true vitamin while carotenoids and carotenes are considered to be provitamins. These provitamins are metabolized in the body into the true vitamin form. This vitamin is fat soluble: exaggerated intake likely to lead to hypervitaminosis.

nutshell In a nutshell
nutshell Vitamin A very important for healthy eyes and vision, skin health, immune system, reproductive function, and body development.
nutshell Obtaining too little or continually too much of vitamin A can cause adverse effects to health.
nutshell Vitamin A was the first discovered vitamin.

Vitamin A deficiency


Vitamin A deficiency is not common in developed countries. Deficiencies can cause blindness, with the first stage being night blindness. Cornea loses its ability to adjust to low light levels. Recurrent conjunctivitis, or inflammation of the eye. Without enough of this vitamin, the body is unable to fight infection properly. Those affected with illnesses have a greater risk of developing serious complications and side effects. Growth and development can be slowed, infertility and other reproductive problems. The following skin problems also are associated with vitamin A deficiency: dry skin, acne and eczema, wrinkles and other signs of aging, skin cancer.

Vitamin A overdose


Vitamin A overdose. As this vitamin is stored in the body, it is possible to take too much and lead to overdose. Symptoms include nausea, headache, irritability, loss of appetite, loss of hair, skin peeling. Fatigue, blurry vision, and abdominal tenderness caused by enlarged organs, such as the spleen and liver. Overdose of this vitamin can be fatal. It typically occurs from taking too many vitamin supplements. However, certain food products, such as cod liver oil, may contain large amounts of this vitamin as well and should be used in moderation.

Daily Recommended Intake and sources of vitamin A


Daily Recommended Intake. Healthy individuals aged 14 and older need different doses depending on their gender. Females should get 700 micrograms (μg) and males 900 micrograms (μg) of this vitamin- 3,000 IU (international units of vitamin A equivalent). It is always best to get your vitamins and minerals from natural sources. Retinol (true vitamin) is found in meat sources, while beta-carotene (proviamin) is found in plant sources. Retinol is also available in certain topical creams, such as those to treat acne and anti-aging creams.

The following foods have high amounts of vitamin A:
• cod liver oil (100g) – 30000 μg of vitamin A equivalent
• turkey liver (100g) -8058 μg of vitamin A equivalent
• beef, pork liver (100g) – 6500 μg of vitamin A equivalent
• chicken liver (100g) – 3296 μg of vitamin A equivalent
• carrots (100g) – 835 μg of vitamin A equivalent
• sweet potato (100g) -709 μg of vitamin A equivalent
• butter (100g) – 684 μg of vitamin A equivalent
• kale (100g) – 681 μg of vitamin A equivalent
• spinach (100g) -469 μg of vitamin A equivalent

Other important sources of Vitamin A:
• pumpkin; pea; broccoli; tomatoes;
• apricot; papaya; mango;
• cheddar cheese; milk;
• eggs.

Why “A”?


Why “A”? This vitamin is labeled “A”, not for creative purposes, but simply because it was the first vitamin to be discovered by science. Researchers found that there were other nutrients in food that were important to human health other than proteins, fats, and carbohydrates. Elmer McCollum isolated this vitamin in 1912, as did Lafayette Mendel and Thomas Burr Osborne in independently run research in 1913.