Vitamin A: what it does, how much you need, and how much is too much
By Vita · fact-checked against NIH ODS
Vita is Vitaminico's AI nutrition coach. Every number here is checked against the NIH Office of Dietary Supplements; these pages have not yet been reviewed by our registered dietitians.
A fat-soluble vitamin for vision, immunity, and growth, from animal foods and plants
Vitamin A: key facts
- Everyday need (RDA/AI)
- 900 mcg RAE for men, 700 mcg RAE for women (900 mcg RAE = 3,000 IU as preformed vitamin A)
- Safe upper limit (UL)
- 3,000 mcg (preformed vitamin A/retinol only)
- Measured in
- mcg
- Best foods
- Beef liver and organ meats, fish, eggs, dairy, plus provitamin A from sweet potatoes, carrots, and leafy greens
Adult values from the NIH ODS Vitamin A fact sheet. Needs differ in pregnancy, lactation and childhood.
What does vitamin a do?
Vitamin A supports normal vision (especially seeing in dim light), a healthy immune system, reproduction, and growth and development, and it helps your heart, lungs, kidneys, and other organs work properly. It comes in two forms: preformed vitamin A (retinol), found in animal foods like liver, fish, eggs, and dairy, and provitamin A carotenoids such as beta-carotene, found in colorful fruits and vegetables. Your body converts the carotenoids into active vitamin A as it needs them.
Why you might be low on vitamin a
- Premature infants, who are born with low vitamin A stores because most of it is built up in the last trimester
- Cystic fibrosis and other conditions with pancreatic insufficiency, which cause poor absorption of fat and fat-soluble vitamins
- Crohn's disease, ulcerative colitis, or celiac disease, which impair how the gut absorbs fat-soluble vitamins
- Taking the weight-loss drug orlistat (Alli, Xenical), which reduces vitamin A absorption
- A diet very low in animal foods and colorful produce, or limited food access (frank deficiency is rare in the US but common in some low-income countries)
Signs of low vitamin a
These are common signals, not a diagnosis — a blood test and your clinician confirm a real gap.
- Night blindness, trouble seeing in dim light or darkness, which is usually the earliest sign
- Dry eyes (xerophthalmia); if untreated this can progress to corneal damage and permanent blindness
- Dry, rough skin
- Getting infections more often or more severely because immune defenses weaken
- Higher risk of anemia
- In children, impaired growth and greater risk of respiratory infections such as pneumonia
Best food sources of vitamin a
| Food | Typical amount |
|---|---|
| Beef liver, pan-fried (3 oz) | 6,582 mcg RAE (731% DV) |
| Sweet potato, baked in skin (1 whole) | 1,403 mcg RAE (156% DV) |
| Spinach, frozen then boiled (1/2 cup) | 573 mcg RAE (64% DV) |
| Carrots, raw (1/2 cup) | 459 mcg RAE (51% DV) |
| Fortified skim milk, with added vitamin A and D (1 cup) | 149 mcg RAE (17% DV) |
| Cantaloupe, raw (1/2 cup) | 135 mcg RAE (15% DV) |
| Egg, hard-boiled (1 large) | 75 mcg RAE (8% DV) |
How much vitamin a is too much?
The tolerable upper intake level (UL) for adults is 3,000 mcg (preformed vitamin A/retinol only) per day. The UL applies only to preformed vitamin A (retinol) — beta-carotene from plants is not counted; excess preformed vitamin A can cause birth defects and liver damage.
Too much preformed vitamin A (from supplements, liver, or certain acne and psoriasis drugs) can build up and cause harm; the upper limit for adults is 3,000 mcg RAE per day. Excess can cause severe headache, blurred vision, nausea, dizziness, aching muscles and joints, liver damage, and, in pregnancy, serious birth defects. Beta-carotene from food does not cause this toxicity, though high-dose beta-carotene supplements raise lung cancer risk in people who smoke.
Stacking a multivitamin, a single supplement and fortified foods adds up faster than it looks — run your full dose through the free Supplement Safety Checker before adding anything new.
Vitamin A FAQ
Are carrots or beta-carotene from food dangerous?
No. Your body only converts as much beta-carotene into vitamin A as it needs, so plant carotenoids don't cause vitamin A toxicity. Eating a lot can tint the skin a harmless yellow-orange that fades once you cut back. The real overdose risk comes from preformed vitamin A in supplements and liver. One caveat: high-dose beta-carotene supplements have been shown to increase lung cancer risk in current and former smokers.
Do I need a vitamin A supplement?
Most people in the US get enough from food and true deficiency is rare, so a supplement usually isn't necessary. Adult men need about 900 mcg RAE a day and women about 700 mcg RAE, amounts easily met with a varied diet. Because too much preformed vitamin A can be harmful, don't take high-dose vitamin A unless a clinician advises it.
I'm pregnant. How much vitamin A is safe?
You do need vitamin A in pregnancy (about 770 mcg RAE a day), and a balanced diet plus a standard prenatal vitamin covers it. Avoid high-dose preformed vitamin A supplements and go easy on liver, because excess preformed vitamin A can cause birth defects. Beta-carotene from fruits and vegetables is not a concern.
Source
Every RDA/AI, upper limit and unit on this page is drawn from the NIH Office of Dietary Supplements Vitamin A fact sheet ›.
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Educational, not medical advice. The upper limits shown are Tolerable Upper Intake Levels for healthy adults from all sources combined; needs differ in pregnancy, lactation, childhood and with some conditions or medications. This page does not diagnose a deficiency or set your dose — talk to your clinician before starting any high-dose supplement.