What are the Most Important Sources of Vitamin A?

The Biochemistry Online – Free Online Lectures for Medical, Dental and Allied Health Sciences students by the Biochemistry Club.

Sources of Vitamin A

Animal Sources of Vitamin A

  1. Liver especially that of  fish, polar bear
  2. Butter
  3. Milk
  4. Cheese
  5. Egg yolk

Plant Sources of Vitamin A

  • In plants it is found in the form of Provitamin carotene.
  • It is found in:
  1. Tomatoes
  2. Carrots
  3. Green-yellow vegetables
  4. Spinach &
  5. Fruits (mangoes, papaya, corn, sweet potatoes).
  6. Algae are also good source.

Daily Requirement of Vitamin A

  • Adults:
    Daily requirement for males & females is 3000 I.U. per day.
    Recommended Daily Allowance (RDA) is 5000 I. U. per day.
  • Higher Requirements in:
    Growing children
    Pregnant women
    Lactating mothers
  • Normal blood level:
    Vitamin A is 18-60 µg/dl.
    Carotenoids is 100-300 µg/dl.

Structure of Vitamin A

  • In the structure of Vitamin A, the side chain contains alternate double bonds.
  • Due to the presence of a number of double bonds many isomers are possible.
  • The all-trans variety of retinal, also called Vitamin A1 is the most common type.
  • Vitamin A2 is found in fish oils and has an extra double bond in the ring.
  • Biologically important compound of Vitamin A  is the 11-cis-retinal.
All these lectures are organized and listed in detail in their proper sections. To view these lessons please visit the Vitamins Section in Biochemistry I. This can be approached by directly clicking the Biochemistry I button or it can also be approached from the drop down menu in Biochemistry I tab. Once you reach the section click the curriculum tab to view the full list in the section.
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