Vitamin A
Also known as: Retinol, Beta-Carotene, Retinoid, Provitamin A
Vitamin A is a fat-soluble vitamin essential for vision, immune function, skin health, and cellular differentiation. It exists in two forms: preformed vitamin A (retinol) found in animal products and provitamin A (carotenoids) from plant sources. Vitamin A is critical for maintaining the structure and function of the retina and supporting normal cell growth and development.
Benefits
Essential for normal vision and prevents night blindness. Strengthens immune function by supporting antibody production and white blood cell activity. Promotes healthy skin and may reduce acne when used appropriately. Supports bone health and growth. Acts as a powerful antioxidant protecting cells from damage. May reduce risk of age-related macular degeneration.
Recommended Dosage
RDA: 900 mcg/day for men, 700 mcg/day for women. Common supplement doses: 2,500–10,000 IU daily. Upper limit: 3,000 mcg/day from preformed vitamin A (not including beta-carotene). Beta-carotene has no upper limit but very high doses may increase risk. Take with fat-containing meals for optimal absorption. Avoid excessive supplementation during pregnancy.
Food Sources
Liver, sweet potatoes, carrots, spinach, kale, collard greens, broccoli, butternut squash, pumpkin, cantaloupe, apricots, bell peppers, eggs, cheese, salmon, beef.
Side Effects
Excessive vitamin A (above 3,000 mcg/day) causes vitamin A toxicity: headaches, nausea, dizziness, skin peeling, joint pain. Chronic toxicity can cause liver damage and bone loss. Beta-carotene at very high doses may increase lung cancer risk in smokers. Some people experience photosensitivity or hair loss with excess.
Interactions
Vitamin E and vitamin K absorption may be affected by vitamin A levels. Retinoid medications (isotretinoin, tretinoin) should not be combined with high-dose vitamin A. Mineral oil laxatives reduce absorption. May interact with anticonvulsants.
Warnings
Pregnant women should avoid high-dose vitamin A (teratogenic risk). People with liver disease should consult before supplementing. Beta-carotene supplementation not recommended for smokers or former smokers due to lung cancer risk. Those with kidney disease should be cautious.
Deficiency Symptoms
Night blindness is the earliest sign. Progressive vision loss, dry eyes (xerophthalmia), corneal damage, increased infection susceptibility, poor wound healing, dry and scaly skin, loss of appetite, fatigue.
Frequently Asked Questions
What are the benefits of Vitamin A?▼
Essential for normal vision and prevents night blindness. Strengthens immune function by supporting antibody production and white blood cell activity. Promotes healthy skin and may reduce acne when used appropriately. Supports bone health and growth. Acts as a powerful antioxidant protecting cells from damage. May reduce risk of age-related macular degeneration.
What is the recommended dosage for Vitamin A?▼
RDA: 900 mcg/day for men, 700 mcg/day for women. Common supplement doses: 2,500–10,000 IU daily. Upper limit: 3,000 mcg/day from preformed vitamin A (not including beta-carotene). Beta-carotene has no upper limit but very high doses may increase risk. Take with fat-containing meals for optimal absorption. Avoid excessive supplementation during pregnancy.
What foods contain Vitamin A?▼
Liver, sweet potatoes, carrots, spinach, kale, collard greens, broccoli, butternut squash, pumpkin, cantaloupe, apricots, bell peppers, eggs, cheese, salmon, beef.
What are the side effects of Vitamin A?▼
Excessive vitamin A (above 3,000 mcg/day) causes vitamin A toxicity: headaches, nausea, dizziness, skin peeling, joint pain. Chronic toxicity can cause liver damage and bone loss. Beta-carotene at very high doses may increase lung cancer risk in smokers. Some people experience photosensitivity or hair loss with excess.
What are the symptoms of Vitamin A deficiency?▼
Night blindness is the earliest sign. Progressive vision loss, dry eyes (xerophthalmia), corneal damage, increased infection susceptibility, poor wound healing, dry and scaly skin, loss of appetite, fatigue.
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Supplement Disclaimer
This supplement information is for educational purposes only and should not replace professional medical advice. Dietary supplements are not intended to diagnose, treat, cure, or prevent any disease. Always consult with a healthcare provider before starting any supplement, especially if you are pregnant, nursing, taking medications, or have a medical condition.