Vitamin A is a fat-soluble vitamin. It can be found in many fruits, vegetables, eggs, whole milk, butter, fortified margarine, meat, and oily saltwater fish. It can also be made in a laboratory. Carotenoids are a group of yellow or orange chemicals found in plants. Some of these can be converted to vitamin A in the body.
Vitamin A is most commonly used for treating vitamin A deficiency.
People also use vitamin A to reduce complications of diseases such as malaria, HIV/AIDS, and measles, and for fertility, diarrhea, vision, child development, skin disorders, infections, and many other conditions, but there is no good scientific evidence to support most of these uses.
Is a Form of:
Vitamin A deficiency
Also Known As:
3-Dehydroretinol, 3-Déhydrorétinol, Acétate de Rétinol
How Does It Work?
Vitamin A is required for the proper development and functioning of our eyes, skin, immune system, and many other parts of our bodies.
- Vitamin A deficiency.Taking vitamin A by mouth is effective for preventing and treating symptoms of vitamin A deficiency. Vitamin A deficiency can occur in people with protein deficiency, diabetes, over-active thyroid, fever, liver disease, cystic fibrosis, or an inherited disorder called abetalipoproteinemia.
- Breast cancer. Premenopausal women with a family history of breast cancer who consume high levels of vitamin A in their diet seem to have lower risk of breast cancer. It is not known if taking vitamin A supplements has the same benefit.
- Cataracts. People who consume high amounts of vitamin A in their diet seem to have a lower risk of developing cataracts.
- Measles. Taking vitamin A by mouth seems to reduce the risk of measles complications or death in children with measles and vitamin A deficiency.
- Ability to see in low-light conditions. Taking vitamin A during pregnancy seems to reduce night blindness by 37% in malnourished women. Vitamin A might work better for this condition when taken with zinc.
- White patches inside the mouth that are usually caused by smoking (oral leukoplakia). Research shows that taking vitamin A can help treat precancerous lesions in the mouth.
- Death from any cause. Most experts agree that high-dose vitamin A supplementation reduces the risk of death in children 6-59 months of age who are at risk for vitamin A deficiency. Taking vitamin A does not seem to reduce the risk of death in healthy adults.
- Complications after childbirth. Taking vitamin A, during, and after pregancy reduces diarrhea after giving birth in malnourished women. Taking vitamin A before and during pregnancy also seems to reduce the risk of death by 40% in malnourished women.
- An inherited eye condition that causes poor night vision and loss of side vision (retinitis pigmentosa). Taking vitamin A can slow the progression of an eye disease that causes damage to the retina.
- A type of inflammatory bowel disease (ulcerative colitis). Some research shows that taking vitamin A daily for 2 months can reduce symptoms and help the intestine to heal in adults with ulcerative colitis.
The following doses have been studied in scientific research:
- General: The Recommended Dietary Allowance (RDA) levels for vitamin A are 900 mcg daily for men and 700 mcg daily for women. For women who are pregnant, the RDA is 770 mcg daily. For women who are breast-feeding, the RDA is 1,300 mcg daily.
The tolerable Upper Intake Level (UL) for vitamin A is 10,000 units (3,000 mcg) daily. The UL is the highest level of intake that is likely to pose no risk of harmful effects. The UL for vitamin A is for preformed vitamin A (retinol) and does not include provitamin A carotenoids.
Vitamin A dosage is most commonly expressed in IU, but dosing in micrograms is sometimes used.
Eating 5 servings of fruits and vegetables per day provides about 50% to 65% of the adult RDA for vitamin A.
- For white patches inside the mouth that are usually caused by smoking (oral leukoplakia): Weekly dose of 200,000-300,000 IU of vitamin A has been used for 6-12 months.
- For complications after childbirth: Weekly doses of 23,000 IU of vitamin A have been used before, during, and after pregnancy. Weekly doses of 23,000 IU of vitamin A have been used before and during pregnancy.
- For ability to see in low-light conditions: Weekly doses of 23,000 IU of vitamin A have been used before, during, and after pregnancy. It seems to work best if taken in combination with 35 mg of zinc daily in women who also have low levels of zinc.
- For an inherited eye condition that causes poor night vision and loss of side vision (retinitis pigmentosa): Daily doses of 15,000 IU of vitamin A, sometimes along with 400 IU of vitamin E daily, has been used.
- A type of inflammatory bowel disease (ulcerative colitis): Vitamin A 25,000 IU daily has been used for 2 months.
- General: Recommended Dietary Allowance (RDA) levels of vitamin A are: birth to 6 months, 400 mcg/day; 7 to 12 months, 500 mcg/day; 1 to 3 years, 300 mcg/day; 4 to 8 years, 400 mcg/day; 9 to 13 years, 600 mcg/day; 14-18 years, 900 mcg/day. For girls 14-18 years of age who are pregnant, the RDA is 750 mcg. For girls 14-18 years of age who are lactating, the RDA is 1,200 mcg.
Tolerable Upper Intake Levels (UL) for vitamin A have also been established. The UL is the highest level of intake that is likely to pose no risk of harmful effects. The ULs for vitamin A are for preformed vitamin A (retinol) and do not include provitamin A carotenoids. For birth to 3 years, 600 mcg/day (2,000 units); 4 to 8 years, 900 mcg/day (3,000 units); 9 to 13 years, 1700 mcg/day (5,667 units); and 14 to 18 years, 2800 mcg/day (9,333 units).
- For measles: 100,000 to 200,000 IU of vitamin A for at least two doses has been used in children less than 2 years-old.
- For death of an unborn or premature baby: Vitamin A supplements are recommended for children 6-59 months of age who are at risk of vitamin A deficiency. For children ages 6-11 months, one dose providing 100,000 IU of vitamin A is recommended. For children ages 12-59 months, 200,000 IU of vitamin A every 4-6 months in recommended.
Vitamin A Supplements Frequently Asked Questions
Should I take a vitamin A supplement?
The tolerable upper intake levels of a supplement are the highest amount that most people can take safely. Higher doses might be used to treat vitamin A deficiencies. But you should never take more unless a doctor says so. * There is no upper limit for vitamin A from beta-carotene.
What does vitamin A pills do?
Vitamin A is a fat-soluble vitamin that is naturally present in many foods. Vitamin A is important for normal vision, the immune system, and reproduction. Vitamin A also helps the heart, lungs, kidneys, and other organs work properly.
Can I take vitamin A capsules daily?
Vitamin A Dosage
Vitamin A comes in capsules of 8,000, 10,000, 15,000, and 25,000 international units (IU) and is included in some multivitamins. The Tolerable Upper Intake Level (UL) of vitamin A for men and women over 18 years old is 3,000 micrograms (mcg) or 10,000 IU a day.
How much vitamin A should I take?
The recommended daily allowance (RDA) for vitamin A is 900 mcg and 700 mcg per day for men and women, respectively — which can be easily reached by following a whole-foods diet (27). However, it's important not to exceed the tolerable upper limit (UL) of 10,000 IU (3,000 mcg) for adults to prevent toxicity (27).
Who should not take vitamin A?
These birth defects can include malformations of the eye, skull, lungs, and heart . Women who might be pregnant should not take high doses of vitamin A supplements . Unlike preformed vitamin A, beta-carotene is not known to be teratogenic or lead to reproductive toxicity .
Why Vitamin A is bad for you?
Yes, high intakes of some forms of vitamin A can be harmful. Getting too much preformed vitamin A (usually from supplements or certain medicines) can cause dizziness, nausea, headaches, coma, and even death. High intakes of preformed vitamin A in pregnant women can also cause birth defects in their babies.
Does vitamin A help immune system?
Vitamin A (VitA) is a micronutrient that is crucial for maintaining vision, promoting growth and development, and protecting epithelium and mucus integrity in the body. VitA is known as an anti-inflammation vitamin because of its critical role in enhancing immune function
Does vitamin A help skin?
Vitamin A helps to speed up healing, prevent breakouts and support the skin's immune system and it promotes natural moisturising - which means it helps to hydrate the skin effectively, giving it a radiant glow. It assists in promoting and maintaining a healthy dermis and epidermis; the top two layers of your skin.
Is vitamin A capsules good for skin?
Some vitamin A supplements come in the form of capsules that can be broken open and applied directly to skin. Applied topically, vitamin A can be beneficial for certain skin conditions: Acne. They also help to regulate the sloughing off of skin cells, reducing the occurrence of clogged pores.
Does vitamin A lighten skin?
The Astounding Benefits of Vitamin C for Bright, Even Skin
Vitamin C is an antioxidant, which is an incredibly important quality that plays a role in combating dark spots. Plus, it significantly lightens pigmentation but does not lighten normal skin.
How long does vitamin A stay in the body?
Since vitamin A is stored in the liver, it may take up to 2 years for signs of deficiency to appear.
What are the side effect of vitamin A?
The most common side effects of chronic vitamin A toxicity — often referred to as hypervitaminosis A — include:
- Vision disturbances.
- Joint and bone pain.
- Poor appetite.
- Nausea and vomiting.
- Sunlight sensitivity.
- Hair loss.
- Dry skin.
How much vitamin A is toxic?
The acute toxic dose of vitamin A is 25,000 IU/kg, and the chronic toxic dose is 4000 IU/kg every day for 6-15 months. (Beta-carotene [ie, provitamin A] is converted to retinol but not rapidly enough for acute toxicity.)
Is 5000 IU of vitamin A Safe?
How much vitamin A is enough? Until 2001, the dietary reference intake for adult men was 5,000 international units (IU) a day, or 1,500 micrograms (mcg). Levels of up to 10,000 IU (3,000 mcg) have been considered safe.
Can too much vitamin A cause hair loss?
Diets deficient in vitamin A may lead to several problems, including hair loss ( 3 ). While it's important to get enough vitamin A, too much may be dangerous. Studies show that an overdose of vitamin A can also contribute to hair loss ( 4 ).
What are the benefits of vitamin A?
Here are 6 important health benefits of vitamin A.
- Protects Your Eyes From Night Blindness and Age-Related Decline.
- May Lower Your Risk of Certain Cancers.
- Supports a Healthy Immune System.
- Reduces Your Risk of Acne.
- Supports Bone Health.
- Promotes Healthy Growth and Reproduction.
Should you take vitamin A everyday?
If you take vitamin A for its antioxidant properties, keep in mind that the supplement might not offer the same benefits as naturally occurring antioxidants in food. The recommended daily amount of vitamin A is 900 micrograms (mcg) for adult men and 700 mcg for adult women.
What form of vitamin A is best absorbed?
Vitamin A palmitate is available as a manufactured supplement. Unlike some forms of vitamin A, vitamin A palmitate is a retinoid (retinol). Retinoids are bioavailable substances. This means they are easily absorbed into the body and used efficiently.
Is vitamin A or E better for skin?
Its main function in skin care is to protect against sun damage. Vitamin E absorbs the harmful UV light from the sun when applied to the skin. Photoprotection refers to the body's ability to minimize the damage caused by UV rays. Vitamin E also helps in the treatment of skin inflammation.
- ^ Schreiber R, et al. Retinyl ester hydrolases and their roles in vitamin A homeostasis. Biochim Biophys Acta. (2012)
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- ^ Burri BJ, Chang JS, Neidlinger TR. β-Cryptoxanthin- and α-carotene-rich foods have greater apparent bioavailability than β-carotene-rich foods in Western diets. Br J Nutr. (2011)
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- ^ a b c d Kafi R1, et al. Improvement of naturally aged skin with vitamin A (retinol). Arch Dermatol. (2007)
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- ^ a b Griffiths CE1, et al. Restoration of collagen formation in photodamaged human skin by tretinoin (retinoic acid). N Engl J Med. (1993)
- ^ Quan T1, et al. Solar ultraviolet irradiation reduces collagen in photoaged human skin by blocking transforming growth factor-beta type II receptor/Smad signaling. Am J Pathol. (2004)
- ^ a b c d Weiss JS1, et al. Topical tretinoin improves photoaged skin. A double-blind vehicle-controlled study. JAMA. (1988)
- ^ a b c Griffiths CE1, et al. Two concentrations of topical tretinoin (retinoic acid) cause similar improvement of photoaging but different degrees of irritation. A double-blind, vehicle-controlled comparison of 0.1% and 0.025% tretinoin creams. Arch Dermatol. (1995)
- ^ Griffiths CE1, et al. Topical tretinoin (retinoic acid) treatment of hyperpigmented lesions associated with photoaging in Chinese and Japanese patients: a vehicle-controlled trial. J Am Acad Dermatol. (1994)
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