Monday, September 07, 2009

Vitamin A

Vitamin A
Vitamin A (retinol) functions in reproduction, growth, the maintenance of skin and mucous membranes and the visual process.

Vitamin A is normally transported in the blood linked to a specific protein, retinol binding protein (RBP).

Specific proteins on cell surfaces and within cells are also involved with intracellular transport of the vitamin.

Vitamin A is fat soluble and is primarily stored in the liver, where RBP is synthesized. In a well nourished person, vitamin A stores are generally sufficient to last many months on a vitamins A-deficient diet before signs of deficiency appear.

The initial symptoms of vitamin A deficiency are night blindness and keratinization of hair follicles.

Continued deficiency leads to damage to eye tissue and irreversible blindness.

The US recommended Daily Allowance (RDA) of vitamin A for adults is 5000 IU (1000 retinol equivalents).

Rich dietary sources of retinol (preformed vitamin A) include dairy products, eggs and organ meats.

Some carotenoids (found in deep-yellow and dark green vegetables) can be converted to vitamin A during digestion.

In the US diet, approximately half of the vitamin A activity is derived from B-carotene and other carotenoids.
Vitamin A
at
Labels: ,

Popular articles

  • Amylopectin
    Amylopectin is one of the biggest molecules in nature being the principal component in the majority of starches. Starches with varying amylo...
  • Vitamin B in Human Nutrition
    The Vitamin B are water soluble. The vitamin B are utilized as coenzymes in almost all parts of the body. The vitamins that belong to vitami...
  • Niacin deficiency
    First documented in 1735 by a Spanish physician named Gaspar Casal the niacin deficiency disease pellagra was originally named ‘mal de la ro...
  • Antioxidants and Their Measurement Methods
    Antioxidants are vital compounds that can delay or prevent oxidation, a chemical process triggered by atmospheric oxygen or reactive oxygen ...
  • Applications and Benefits of Carrageenan in Food Products
    Carrageenan, extracted from red seaweeds such as Kappaphycus alvarezii and Eucheuma denticulatum , remains one of the most widely used hydr...

My Blog List

  • Food Processing
    Cheese curls are light, crunchy snack foods made primarily from cornmeal. Recognizable by their small, curved shapes and bright cheese coating, they are ...
  • Marketing Strategy And Concept
    Integrated Marketing Communications (IMC) puts the customer at the center of a brand’s storytelling by aligning all marketing channels—advertising, social ...