vitamin A

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Definition

Noun 1. A fat-soluble vitamin essential for normal vision: Vitamin A is a nutrient that the body stores and uses. It is crucial for maintaining healthy eyesight, particularly for seeing in low-light conditions and preventing specific eye disorders. 2. A substance that prevents night blindness and eye dryness: It refers to the specific compound or group of compounds (like retinol) whose deficiency leads to impaired vision at night (night blindness) and can cause inflammation or dryness of the eyes.

Usage Examples
  • Noun:
    • Carrots are rich in beta-carotene, which the body converts into vitamin A.
    • A severe deficiency of vitamin A can lead to night blindness.
    • This supplement contains the recommended daily amount of vitamin A.
Advanced Usage
  • "Vitamin A deficiency": A medical condition resulting from insufficient intake of vitamin A.
    • Vitamin A deficiency is a major public health problem in some developing regions.
  • "Preformed vitamin A" (retinol) vs. "Provitamin A" (carotenoids): Distinguishes between the active form found in animal products and the precursor forms found in plants.
    • Liver is a direct source of preformed vitamin A, while spinach provides provitamin A carotenoids.
Variants and Related Words
  • Retinol (n): One of the active, preformed types of vitamin A found in animal sources.
    • Retinol is commonly used in skincare products for its effects on cell renewal.
  • Beta-carotene (n): A red-orange pigment found in plants that the body can convert into vitamin A.
    • Sweet potatoes get their orange color from beta-carotene.
  • Retinoid (n): A class of chemical compounds related to vitamin A, often used in medicine and dermatology.
Synonyms
  • Retinol: Specifically refers to one form of preformed vitamin A.
  • Antixerophthalmic vitamin: An older, technical term highlighting its role in preventing dry eyes (xerophthalmia).
Related Phrases
  • Vitamin A palmitate: A common, stable form of vitamin A used in supplements and fortified foods.
    • The milk is fortified with vitamin A palmitate.
  • Vitamin A activity: A term used to describe the total potential of different compounds (like retinol and carotenoids) to meet the body's vitamin A requirements.
    • Food labels may list vitamin A activity in International Units (IU).
Noun
  1. any of several fat-soluble vitamins essential for normal vision; prevents night blindness or inflammation or dryness of the eyes

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