Vitamin A
General Information
Vitamin A is a fat-soluble vitamin and can be stored in the liver and fat tissues for long periods of time. It is available in two different forms: retinoids and carotenoids. Retinoids, one of the most usable forms of vitamin A, come from animal sources such as eggs, dairy products, liver, and meat. Carotenoids are made into retinol once inside the body; they are found in certain plants such as dark or yellow vegetables, squash, spinach, broccoli, and carrots.
Common Name(s)
vitamin A, retinol
Scientific Name(s)
vitamin A
Scientific Name(s)
Vitamin A is taken by mouth. It is available in different forms, including tablets, chewable tablets or gummies, capsules, powders, strips, drops, and liquids. Retinoids can also be applied topically to the skin in the form of creams for the treatment of acne.
Vitamin A dosage is written in micrograms (µg) or milligrams (mg) of retinol activity equivalents (RAE). Table 1 lists the usual dose and the recommended dietary allowance for vitamin A for different age groups. People with vitamin A deficiency might need doses at or above the RDA.
Both vitamin A and beta-carotene products will contribute to your vitamin A levels and increase your risk of vitamin A overdose. Your vitamin A intake may need to be reduced in these cases. Before taking any vitamin A supplements, let your health care provider know if you are already taking other supplements.
Table 1. Usual daily dose and RDA for vitamin A for different age groups
| Age groups | Vitamin A (µg RAE/day) |
||
RDA |
Usual daily dose |
||
Infants |
0–6 months |
400 |
30–600 |
7–12 months |
500 |
30–600 |
|
Children |
1–3 years |
300 |
30–600 |
4–8 years |
400 |
30–900 |
|
Adolescent males |
9–13 years |
600 |
30–1700 |
14-18 years |
900 |
65–2800 |
|
Adult males |
≥19 years |
900 |
65–3000 |
Adolescent females |
9–13 years |
600 |
30–1700 |
14–18 years |
700 |
65–2800 |
|
Adult females |
≥19 years |
700 |
65–3000 |
Pregnancy |
14–18 years |
750 |
65–3000 |
19–50 years |
770 |
65–3000 |
|
Breast-feeding |
14–18 years |
1200 |
65–3000 |
19–50 years |
1300 |
65–3000 |
|
Your health care provider may have recommended using this product in other ways. Contact a health care provider if you have questions.
What is this product used for?
Vitamin A is important to help maintain overall good health. It helps to maintain healthy eyesight, skin membrane, and immune function. Vitamin A can help develop and maintain night vision, bones, and teeth. At doses at or above the RDA, it is also used to treat vitamin A deficiency, which is a condition that can cause night blindness or slow growth rate in children.
Vitamin A supplementation is effective in the treatment and prevention of vitamin A deficiency.
It may also be used to treat many other conditions such as anemia, ulcerative colitis, and aging or wrinkled skin. There is not enough evidence to support its effectiveness in its uses outside of preventing and treating vitamin A deficiency.
Your health care provider may have recommended this product for other conditions. Contact a health care provider if you have questions.
What else should I be aware of?
Vitamin A is safe for most people when taken in recommended amounts. Large amounts of vitamin A can cause abdominal pain or fullness, bone fractures, brittle nails, changes in menstrual flow, changes in skin colour, hair loss, headaches, diarrhea, dizziness, inflamed gums, loss of appetite, nausea, vomiting, and vision changes.
If large amounts are taken for a long time, you may experience changes in blood cell counts; dry, scaly, and peeling skin; liver damage; tiredness; irritability; psychiatric changes; depression; fever; and coma or even death.
High doses of vitamin A can harm the liver. People who drink alcohol on a regular basis or have liver diseases or are take medications that can affect the liver should consult a health care professional before taking a vitamin A supplement.
People who smoke are at an increased risk of lung cancer if taking vitamin A (specifically beta-carotene). Consult a health care professional if you are currently smoking or recently quit smoking before taking vitamin A supplement.
Avoid taking vitamin A if you have:
- alcohol use disorder
- liver disease
- poor fat absorption
- poor nutritional status
- zinc deficiency
Vitamin A is safe to use if you are pregnant or breast-feeding, provided that you do not take more than the recommended amount. High intake of retinol during pregnancy can cause birth defects.
Vitamin A can interact with certain medications, including selected antibiotics (e.g., tetracyclines), some acne products, medications that can damage the liver, and agents that increase the risk of bleeding (e.g., warfarin). Speak to a pharmacist if you are concerned about this.
Before taking any new medications, including natural health products, speak to your physician, pharmacist, or other health care provider. Tell your health care provider about any natural health products you may be taking.
Source(s)
- Health Canada. Licensed Natural Health Products Database. Multi-Vitamin/Mineral Supplements Monograph. https://webprod.hc-sc.gc.ca/nhpid-bdipsn/atReq.do?atid=multi_vitmin_suppl&lang=eng.
- Natural Medicines Comprehensive Database. Vitamin A.
