Vitamin A


» retinol


Vitamin A

Vitamin A is the name of a group of fat-soluble retinoids, including retinol, retinal, retinoic acid, and retinyl esters.

Two forms of vitamin A are available in the human diet: preformed vitamin A (retinol and its esterified form, retinyl ester) and provitamin A carotenoids. Preformed vitamin A is found in foods from animal sources, including dairy products, fish, and meat (especially liver). By far the most important provitamin A carotenoid is beta-carotene; other provitamin A carotenoids are alpha-carotene and beta-cryptoxanthin. The body converts these plant pigments into vitamin A.

Vitamin A - Role and foods that we find
© 2013. Vitamin A - Role and foods that we find
Health benefits

Vitamin A

•  Increases nighttime visual acuity, improves eyesight and helps in the treatment of many diseases of view in that it allows the formation of purpura eye.

•  Increases resistance to respiratory infections.

•  Helps the normal operation of the immune system. Shortens the illness.

•  Maintain health superficial tissues and internal organs. Help remove pigmentation spots caused by age.

•  Maintain the growth and strengthening of bones and health of skin, hair, teeth and gums.

•  Helps in the treatment of acne, superficial wrinkles and damage as impetigo, furunculosis, burns and open ulcers - when used in external use.

•  Is adjuvant in the treatment of emphysema and hyperthyroidism.

Recommended daily intake

Vitamin A

The units of measurement of vitamin A are: IU (International Units), USP (United States Pharmacopaea) and, more recently, RE (Retinol Equivalents).

Required daily dose for preventive purposes adults is 5,000 IU (1,000 RE) for men and 4.000 (800 RE) for women. For nursing mothers, the daily dose can be increased to 2500 IU in the first six months and 2000 IU for the next six months.

Vitamin A deficiency

Vitamin A

A person with absence of vitamin A is easily recognized: it has poor vision, dry skin and gray, often cracked, hands and / or heel, is often predisposed to respiratory infections, abscesses, acne, is complaining of insomnia and is tired without reason, and the hair is thin and lifeless.

Vitamin A excess

Vitamin A

Because vitamin A is fat soluble, the body stores excess amounts, primarily in the liver, and these levels can accumulate. 

Overcoming months for a daily dose of 50,000 IU can cause toxic effects in adults. More than 18,500 IU daily risk of produce adverse effects in children. Vitamin A intoxication symptoms are hair loss, nausea, vomiting, skin thickening, blurred vision, rash, osteoporosis, menstrual irregularities, tiredness, headache and enlarged liver. Too much vitamin A can be harmful or even fatal. The body converts the dimerized form, carotene, into vitamin A as it is necessary, therefore high levels of carotene are not toxic compared to the ester form.

Vitamin A from plant sources

Vitamin A

- carrots, pumpkin, apples, mangoes, apricots, sweet potatoes, spinach, beets, broccoli, peaches, tomatoes, sweet red peppers, cantaloupe, grapefruit, oranges, oatmeal, papaya, lettuce, asparagus, peas, blueberries, raspberries, strawberries, watermelon, chestnuts, pistachios, walnuts, plums and pears.

Opponents of vitamin A

Vitamin A

- Polyunsaturated fatty acids with carotene can destroy vitamin A in the absence of antioxidants. can not take any responsibility for any adverse effects from the use of plants.

Tips and any other information about health available on are for reference and educational. They can not replace medical advice or diagnosis directly and following investigations and medical examinations. We advise you consult your doctor.


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