Vitamin A is a fat-soluble vitamin crucial for various bodily functions. It's not a single compound, but a group of related organic compounds, all essential nutrients. The term encompasses several forms, including preformed vitamin A (retinol, retinal, retinoic acid) found in animal products, and provitamin A carotenoids (like beta-carotene) found in plants. These carotenoids are converted into vitamin A by the body.
Key Roles of Vitamin A:
- Vision: Vitamin A is vital for maintaining good vision, particularly night vision.
- Bone Growth: It plays a critical role in healthy bone development and growth.
- Reproduction: Essential for proper reproductive function in both males and females.
- Immune System: Contributes to a strong immune system and helps fight infections.
- Cell Growth: Supports the growth and maintenance of epithelial cells, which line the body's internal and external surfaces.
Sources of Vitamin A:
Vitamin A is found in a variety of foods:
- Animal Sources (Preformed Vitamin A): Liver (a particularly rich source), oily fish, eggs, dairy products (milk, cheese, yogurt), and fortified foods.
- Plant Sources (Provitamin A Carotenoids): Dark leafy green vegetables (like spinach and kale), orange and yellow fruits and vegetables (like carrots, sweet potatoes, and apricots).
Dietary supplements containing retinyl acetate or retinyl palmitate (forms of preformed vitamin A) are also available. Beta-carotene, a common provitamin A carotenoid, is also frequently included in supplements. However, the best way to obtain adequate Vitamin A is through a balanced and varied diet.
References:
- National Cancer Institute: https://www.cancer.gov/publications/dictionaries/cancer-terms/def/vitamin-a
- NIH Office of Dietary Supplements: https://ods.od.nih.gov/factsheets/VitaminA-Consumer/
- NHS UK: https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-a/
- Wikipedia: https://en.wikipedia.org/wiki/Vitamin_A
