Vitamin A is a fat-soluble vitamin that plays a crucial role in maintaining vision, supporting the immune system, and promoting healthy skin. It exists in two main forms: preformed vitamin A (retinol and retinyl esters) from animal sources and provitamin A carotenoids (like beta-carotene) found in plant-based foods.
Sources of Vitamin A:
- Animal Sources: Liver, fish liver oils (such as cod liver oil), dairy products (milk, cheese, butter), eggs.
- Plant Sources: Orange and yellow fruits (mangoes, papayas, apricots), orange and green vegetables (carrots, sweet potatoes, spinach, kale), and some green leafy vegetables (broccoli, peas).
Types of Vitamin A:
- Preformed Vitamin A: Found in animal products and is readily used by the body.
- Provitamin A Carotenoids: Found in plant-based foods, which the body converts into active vitamin A as needed.
Nutrition Facts and Health Benefits:
- Vision Health: Essential for maintaining normal vision, especially in low light (night vision).
- Immune Function: Supports the immune system, helping to fight infections.
- Skin Health: Promotes healthy skin by regulating cell production and preventing dryness and acne.
- Reproduction and Growth: Important for normal growth and development, including embryonic development.
- Antioxidant Properties: Acts as an antioxidant, protecting cells from damage caused by free radicals.
Medicine Causes and Diseases:
- Deficiency Diseases: Vitamin A deficiency can lead to night blindness, dry eyes, increased susceptibility to infections, and skin issues like hyperkeratosis.
- Medications: Certain medications, such as cholesterol-lowering drugs (bile acid sequestrants), may interfere with the absorption of vitamin A.
- Chronic Diseases: People with conditions that affect fat absorption (like Crohn’s disease or cystic fibrosis) may have difficulty absorbing vitamin A.
Important Notes:
- Toxicity Risk: Excessive intake of vitamin A from supplements can lead to toxicity symptoms, including nausea, dizziness, and even liver damage.
- Pregnancy and Breastfeeding: Pregnant and breastfeeding women should ensure adequate vitamin A intake for fetal development and lactation support.