What Is Vitamin A? - Benefits, Foods & Function

Instructor: Donna Ricketts

Donna Ricketts is a health educator with 15 years of professional experience designing health and wellness programs for adults and children.

In this lesson, you will learn about Vitamin A and its many health benefits. You will be introduced to foods rich in vitamin A and examine the ways in which vitamin A functions in your body. Also, discover possible health problems that could arise due to insufficient amounts of the vitamin.


Have you ever had trouble seeing at night? Maybe you've been bothered by constant bloodshot eyes -- and it's not because you haven't been getting any sleep? It may be that your diet is lacking vitamin A.

Inside the body, vitamins are used in many unique ways. In the case of vitamin A, the eyes have it. Vitamin A is a fat-soluble vitamin that is stored in your liver until your body needs it. There are two types of Vitamin A: retinol and beta-carotene.

Retinol (or 'preformed' vitamin A) is the truest form of vitamin A, and it can be found in animal foods such as oily fish and liver. It is absorbed up to four times more efficiently than beta-carotene.

Beta-carotene, also known as 'pro-vitamin A,' is found in fruits and vegetables. It has to be converted in the body before it can be used. Therefore, it relies more heavily on fats in the diet than does retinol.


Vitamin A has many health benefits. It is essential for normal growth, skeletal development, reproduction, lactation and the maintenance of the nervous system. It helps build and maintain good vision, strong bones, healthy teeth, skin, hair and gums. Vitamin A in the form of beta-carotene is an antioxidant, which helps protect your cells from damage caused by free radicals. Beta-carotene may also help protect you from developing some cancers.

A major benefit of Vitamin A is that it helps treat deficiency syndromes such as:

  • poor night vision
  • extreme dryness of the eyes
  • dry and rough skin
  • susceptibility to infectious diseases
  • weakened immune system

Despite its benefits, too much Vitamin A can cause toxicity. It is highly recommended that adults 19 years and older do not consume more that 10,000 IU's of preformed vitamin A daily.


Vitamin A can be found in both animal and plant foods. Here are some food source examples of both:

Food sources of beta-carotene

  • Apricots
  • Butternut squash
  • Cantaloupe
  • Carrots
  • Kale
  • Spinach
  • Sweet potatoes


Food sources of retinol

  • Butter
  • Cheese
  • Eggs
  • Whole milk
  • Liver
  • Oily saltwater fish



The main function of vitamin A is to support vision, particularly night vision. It helps form pigments that allow your eyes to adjust to changes in light.

Although vitamin A's chief function involves your eyes, it is also needed for normal functioning of the immune system. It helps form white blood cells, which fight off viruses and bacteria.

Often added to skin creams, vitamin A helps treat skin problems such as severe acne but requires medical supervision.

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