Vitamin A
What is Vitamin A?
Image Credit: https://pubchem.ncbi.nlm.nih.gov/compound/Retinol
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. It also helps the heart, lungs, kidneys, and other organs work properly.
There are two types of Vitamin A: preformed vitamin A and provitamin A.
Preformed vitamin A is found in meat, poultry, fish, and dairy products. Provitamin A can be found in fruits, vegetables, and other plant-based products. The most common type of provitamin A in foods and dietary supplements is beta-carotene.
How much vitamin A do I need?
The amount of vitamin A you need is based on your age and sex. Average daily amounts are listed as micrograms (mcg) of retinol activity equivalents (RAE).
Age | Recommended Daily Amount |
|---|---|
Birth to 6 months | 400 mcg RAE |
Infants 7-12 months | 500 mcg RAE |
Children 1-3 years | 300 mcg RAE |
Children 4-8 years | 400 mcg RAE |
Children 9-13 years | 600 mcg RAE |
Teen boys 14-18 years | 900 mcg RAE |
Teen girls 14-18 years | 700 mcg RAE |
Adult men | 900 mcg RAE |
Adult women | 700 mcg RAE |
Pregnant teens | 750 mcg RAE |
Pregnant women | 770 mcg RAE |
Breastfeeding teens | 1200 mcg RAE |
Breastfeeding women | 1300 mcg RAE |
Can I take too much Vitamin A?
Yes. High intake of Vitamin A can be harmful.
Getting too much of preformed vitamin A (usually from supplements or certain medicines) can cause dizziness, nausea, headaches, coma, and even death. High
intakes in pregnant women can also cause birth defects.
Consuming too much of provitamin A or beta-carotene can turn the skin yellow-orange. However, this is harmless. High intakes of beta-carotene do not cause birth defects or the other serious effects of getting too much preformed vitamin A.
The daily upper limits for preformed vitamin A are listed in the table below. This limits include intake from all sources – food, beverages, and supplements.
Age | Daily Upper Limit |
|---|---|
Birth to 12 months | 600 mcg |
Children 1-3 years | 600 mcg |
Children 4-8 years | 900 mcg |
Children 9-13 years | 1700 mcg |
Teens 14-18 years | 2800 mcg |
Adults 19 and older | 3000 mcg |
Does Vitamin A interact with medications?
Vitamin A supplements can interact with the following medications:
• Orlistat (Alli, Xenical) – can decrease the absorption of vitamin A.
• Synthetic vitamin A medications (acitretin (Soriatane), bexarotene (Targretin)) – taking vitamin A supplements with these medications can lead to dangerously high levels of vitamin A in the bloodstream.
Always check with your doctor or pharmacist before starting any new supplements.
Sources:
https://ods.od.nih.gov/factsheets/VitaminA-Consumer/