What does Vitamin A do in the body?

Vitamin A supports vision (including low-light vision), immune function, and the maintenance of skin and mucous membranes. It also helps regulate cell growth and differentiation.

What are the main forms of Vitamin A?

Preformed Vitamin A (retinol and retinyl esters) comes from animal foods and supplements. Provitamin A carotenoids (such as beta carotene) come from plant foods and can be converted to retinol in the body.

What foods are high in Vitamin A?

Retinol is found in liver, dairy, and eggs. Carotenoids are found in orange and dark-green produce such as carrots, sweet potatoes, spinach, and kale.

How much Vitamin A should I take?

Needs vary by age, sex, and pregnancy status; a typical supplemental range is about 750–1500 mcg. Because Vitamin A is fat-soluble, avoid high-dose supplements unless advised by a clinician.

Can you get too much Vitamin A?

Yes—excess preformed Vitamin A (retinol), especially from supplements, can cause toxicity. High intakes are a particular concern during pregnancy and in people using multiple fortified products or supplements.

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Vitamin A

Strong study situation·10/10

A higher score indicates better study conditions, but not necessarily effectiveness.

Essential fat-soluble vitamin important for vision, immunity, and cell health; excess intake can cause toxicity, especially from supplements.

Eye Health Tissue Repair Essential Nutrient Immune Booster Skin Health

dose range

750–1500 µg

Once daily with a meal containing fat, or as part of a multivitamin.

Consumption

Take with a fat-containing meal to enhance absorption; available as retinol (animal source), retinyl esters, or mixed with multivitamins.

Fat-soluble: take with fat.

Best time

Best absorbed with the main meal of the day; morning or lunch preferred for compliance, but no critical time dependency.

Description

Vitamin A is a group of fat-soluble compounds that play key roles in vision, immune function, reproduction, and cellular communication. It is obtained from animal-derived retinol and plant-based carotenoids (provitamin A), with requirements varying by age, sex, and physiological state (e.g., pregnancy).

benefits

Main effects with level of evidence

Strong

Note on evidence

Benefits for vision, immunity, and cell health are well established; risks with excess intake, especially from preformed vitamin A, are well documented.

Supports Night and Color Vision

Strong

Vitamin A is required for the synthesis of rhodopsin, essential for low-light and color vision.

Particularly relevant for: general · older adults · people with poor vision

NIH · Office of Dietary Supplements – Vitamin A Fact Sheet NHS · NHS UK – Vitamin A Overview

Enhances Immune Function

Strong

Vitamin A maintains the integrity of mucosal barriers and supports immune cell differentiation, reducing susceptibility to infections.

Particularly relevant for: general · children · immunocompromised

NIH · Office of Dietary Supplements – Vitamin A Fact Sheet Examine · Examine.com – Vitamin A

Supports Skin and Mucous Membrane Health

Moderate

It is necessary for the maintenance and repair of epithelial tissues, promoting healthy skin and mucous membranes.

Particularly relevant for: general

NIH · Office of Dietary Supplements – Vitamin A Fact Sheet Healthline · Healthline – Vitamin A: Benefits and Sources

Supports Growth and Development

Moderate

Vitamin A is crucial for cellular differentiation and organ development, particularly in children and during pregnancy.

Particularly relevant for: children · pregnant

NIH · Office of Dietary Supplements – Vitamin A Fact Sheet EFSA · EFSA Panel on Dietetic Products, Nutrition and Allergies (2015) – Vitamin A

Safety & Information

Important safety information & known risks

For educational purposes only • not medical advice

Vitamin A is essential but has a narrow therapeutic range; both deficiency and excess can cause significant health issues.

warning notices

Toxicity can occur with chronic intake above the UL, particularly from animal sources or supplements.
High-dose intake in pregnancy is teratogenic and should be avoided unless prescribed.
Chronic excess causes symptoms like headaches, liver damage, bone fractures, and birth defects.
Do not exceed 3,000 mcg RAE/day of preformed vitamin A from supplements due to risk of toxicity.
Avoid high-dose vitamin A supplements during pregnancy unless prescribed by a healthcare provider.
High beta-carotene supplements are contraindicated in smokers due to increased lung cancer risk.
Individuals with liver disease should avoid vitamin A supplements unless under medical supervision.
Vitamin A may interact with retinoid drugs and anticoagulant medications; monitor use together.

Known interactions with medications

systemic retinoids
anticoagulants

Contraindications / special precautions

Pregnancy (for high-dose retinol supplements)
Liver disease
Smoking (for high-dose beta-carotene supplements)

interactions

Important interactions between active ingredient ↔ supplement / medication / food

Vitamin A interacts with some drugs, nutrients, and lifestyle factors affecting absorption, metabolism, or toxicity risk.

Do not combine high-dose vitamin A supplements with prescription retinoids.

drug · systemic retinoids

AvoidStrong

Why

Combining can cause toxicity due to additive effects on vitamin A levels.

recommendation

Avoid combined use unless under specialist supervision.

NIH · Office of Dietary Supplements – Vitamin A Fact Sheet

Vitamin A may increase bleeding risk when combined with anticoagulants.

drug · anticoagulant medications

MonitorModerate

Why

High doses may antagonize vitamin K, potentially increasing bleeding.

recommendation

Monitor INR or clotting status if combined.

NIH · Office of Dietary Supplements – Vitamin A Fact Sheet

Zinc deficiency impairs vitamin A metabolism and transport.

nutrient · Zinc

PairModerate

Why

Zinc is needed for the synthesis of retinol-binding protein and for conversion of retinol to retinal.

recommendation

Ensure adequate zinc intake for optimal vitamin A status.

NIH · Office of Dietary Supplements – Vitamin A Fact Sheet Examine · Examine.com – Vitamin A

Avoid high-dose beta-carotene supplements if you smoke.

lifestyle · smoking

AvoidStrong

Why

High-dose beta-carotene may increase risk of lung cancer in smokers.

recommendation

Do not use beta-carotene-containing vitamin A supplements if you smoke or have smoked heavily in the past.

PubMed2 · Alpha-Tocopherol, Beta Carotene Cancer Prevention Study Group (1994) – The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers NIH · Office of Dietary Supplements – Vitamin A Fact Sheet

mechanisms of action

Brief explanations of how it works

Photoreceptor Function and Visual Cycle

Vitamin A (as retinal) is a critical component of rhodopsin, necessary for vision in low-light conditions.

NIH · Office of Dietary Supplements – Vitamin A Fact Sheet NHS · NHS UK – Vitamin A Overview

Epithelial Maintenance and Immunity

Vitamin A supports healthy mucosal surfaces and modulates immune cell differentiation, reducing susceptibility to infections.

NIH · Office of Dietary Supplements – Vitamin A Fact Sheet Examine · Examine.com – Vitamin A

Sources & References

Primary literature and reviews on which these statements are based

8 sources

NIH

Office of Dietary Supplements – Vitamin A Fact Sheet

Examine

Examine.com – Vitamin A

EFSA

EFSA Panel on Dietetic Products, Nutrition and Allergies (2015) – Vitamin A

PubMed1

Penniston & Tanumihardjo, Am J Clin Nutr (2006) – Vitamin A toxicity

NHS

NHS UK – Vitamin A Overview

Healthline

Healthline – Vitamin A: Benefits and Sources

Cochrane

Cochrane Review: Vitamin A supplementation for preventing morbidity and mortality in children from six months to five years of age

PubMed2

Alpha-Tocopherol, Beta Carotene Cancer Prevention Study Group (1994) – The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers

Laatst bijgewerkt: 7 maart 2026

This information is for educational purposes only and does not replace medical advice.

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Vitamin A

Description

benefits

Supports Night and Color Vision

Enhances Immune Function

Supports Skin and Mucous Membrane Health

Supports Growth and Development

Safety & Information

interactions

Do not combine high-dose vitamin A supplements with prescription retinoids.

Vitamin A may increase bleeding risk when combined with anticoagulants.

Zinc deficiency impairs vitamin A metabolism and transport.

Avoid high-dose beta-carotene supplements if you smoke.

mechanisms of action

Photoreceptor Function and Visual Cycle

Epithelial Maintenance and Immunity

Sources & References

Vitamins & Vitaminoids

Andere categorieën

Safety & Information

interactions

Do not combine high-dose vitamin A supplements with prescription retinoids.

Vitamin A may increase bleeding risk when combined with anticoagulants.

Zinc deficiency impairs vitamin A metabolism and transport.

Avoid high-dose beta-carotene supplements if you smoke.

mechanisms of action

Photoreceptor Function and Visual Cycle

Epithelial Maintenance and Immunity

Sources & References