What Is Vitamin A?

Vitamin A refers to a group of fat-soluble compounds found in both plant and animal foods. In animal products, it's present as retinol and retinyl esters, while in plant foods, it exists as pro-vitamin A carotenoids, such as beta-carotene. These compounds convert into active vitamin A in the body.

Vitamin A plays a vital role in vision, immune response, cognitive performance, and reproductive health. It can be obtained from a balanced diet or taken as a supplement, especially for individuals with poor absorption or dietary limitations.

Supports Eye Health

Vitamin A contributes to the formation of rhodopsin, a pigment in the retina critical for low-light vision. Deficiency in vitamin A may result in night blindness and an increased risk of age-related macular degeneration (AMD). Higher blood levels of carotenoids like beta-carotene can slow AMD progression. Supplementation may also aid people with dry eye disease by improving tear quality.

Boosts Immune System

This vitamin supports immune cells like natural killer (NK) cells and macrophages. It helps the body defend against infections and manage inflammation. Though one study showed reduced COVID-19 symptoms in patients using multiple vitamins including vitamin A, it’s uncertain if vitamin A alone would yield similar results. Always consult a healthcare provider before supplementing.

Essential for Pregnancy

Vitamin A is crucial for fetal development and maternal health. Pregnant and breastfeeding individuals require higher intakes to prevent complications such as anemia, vision problems, and fetal abnormalities. Most prenatal vitamins include vitamin A to maintain healthy levels.

Supports People With Absorption Issues

Conditions like inflammatory bowel disease and cystic fibrosis can impair vitamin A absorption. People with these conditions may need supplements to meet their nutritional requirements. Consult with a healthcare provider to determine appropriate dosage.

Improves Cognitive Function

Beta-carotene has antioxidant properties that may protect brain cells. A review of 16 studies indicated that taking 6–50 mg of beta-carotene with nutrients like vitamins C, E, zinc, or selenium over 16 weeks improved memory and attention. More research is needed to isolate vitamin A's role in brain health.

Top Food Sources

Vitamin A is found in two forms: carotenoids from plants and preformed vitamin A from animal sources. Examples include:

  • Beef liver: 6,582 mcg RAE per 3 oz (731% DV)

  • Raw carrots: 1,070 mcg RAE per cup (119% DV)

  • Spinach: 573 mcg RAE per half cup (64% DV)

  • Cantaloupe: 270 mcg RAE per cup (30% DV)

  • Herring: 219 mcg RAE per 3 oz (24% DV)

  • Ricotta cheese: 133 mcg RAE per cup (15% DV)

  • Red peppers: 117 mcg RAE per cup (13% DV)

  • Mango: 112 mcg RAE per fruit (12% DV)

  • Boiled egg: 75 mcg RAE (8% DV)

People with dietary restrictions should consult a dietitian for tailored vitamin A sources.

How To Take Vitamin A

Vitamin A is available in food, standalone supplements, and multivitamins. As a fat-soluble vitamin, it’s best absorbed with dietary fats. For optimal absorption, take it with meals or snacks containing fat.

Recommended Dosage

Vitamin A needs are measured in retinol activity equivalents (RAE):

  • 1 mcg RAE = 1 mcg retinol

  • 2 mcg supplemental beta-carotene

  • 12 mcg dietary beta-carotene

  • 24 mcg alpha-carotene/beta-cryptoxanthin

RDA for Adults:

  • 700 mcg RAE (female at birth)

  • 900 mcg RAE (male at birth)

  • 770 mcg RAE (pregnant)

  • 1,300 mcg RAE (breastfeeding)

Most supplements range from 750–3,000 mcg RAE.

Safety and Toxicity

While generally safe, excess preformed vitamin A (not carotenoids) may accumulate in the liver, causing toxicity. Acute toxicity may appear after consuming 100x the RDA, while chronic toxicity occurs with prolonged high intake.

Risks include:

  • Birth defects (if taken during pregnancy)

  • Headaches

  • Liver damage

  • Nausea

Carotenoids are safer but may pose risks (e.g., lung cancer in smokers with high beta-carotene intake).

Ensure supplements are third-party tested (NSF, USP, ConsumerLab) since the FDA doesn’t regulate them.

Drug Interactions

Vitamin A may interact with:

  • Orlistat (Alli): Reduces vitamin A absorption.

  • Retinoid medications (e.g., acitretin, bexarotene): Increases toxicity risk.

Discuss with your provider before supplementing, especially if you're on chronic medication.

Can You Overdose?

Yes. The tolerable upper intake level (UL) is:

  • 3,000 mcg RAE or 10,000 IU daily

Exceeding this limit can cause:

  • Headaches

  • Fatigue

  • Dry skin

  • Depression

  • Eye issues

  • Nausea

  • Muscle aches

  • Liver damage

In severe cases, toxicity can lead to coma or death.

A Quick Summary

Vitamin A is essential for vision, immunity, pregnancy, brain health, and more. It’s found in many foods and available in supplement form. However, excessive intake—especially of preformed vitamin A—can be harmful. Always consult a healthcare provider before starting supplementation.