Vitamin A: Sources, Forms, Benefits, Dosage & Deficiency Symptoms

Article at a Glance

  • Vitamin A is one of 13 essential vitamins you need in your diet.
  • Vitamin A is found in retinoids and carotenoids.
  • You can get vitamin A from plants, animal food sources, and nutritional supplements.
  • Vitamin A deficiency is rare in the U.S., but if left untreated it can cause serious eye complications.

Do you ever find yourself cutting evening plans short so you can race home while it’s still light outside? As we get older our eyes change, and the moonlit drives you once enjoyed may now fill you with anxiety. A variety of factors can cause night blindness, but it’s possible that your diet may be lacking vitamin A. Find out how vitamin A affects your eyes and what you can do to get enough of it.

What Is Vitamin A?

Vitamin A is one of the 13 essential vitamins you need in your diet because your body cannot make enough on its own.[1]

Along with being essential, vitamin A is a fat-soluble vitamin, which means it is stored in your liver or fat tissue. Since these vitamins are not easily flushed from your body like water-soluble vitamins, they have the potential to accumulate and cause toxic side effects. However, there is no need to stress since vitamin A toxicity is uncommon, and you would have to take excessively high amounts to reach toxic levels.

Why You Need Vitamin A

Vitamin A is essential for many physiological functions, but it is most popularly known for supporting your eye health. Some of the benefits of vitamin A include: [1], [2]

  • Maintaining the health of your cornea, the outer tissue of your eye that helps you process light
  • Supporting your eyes’ rods, which allow you to see black and white, and cones, which allow you to see color
  • Helping to prevent age-related macular degeneration
  • Reducing the risk of night blindness

 Aside from ocular health, vitamin A supports immunity, bone strength, and cellular functions.[1]

The Forms of Vitamin A

There are two forms of vitamin A: 

  • Retinoids are best for absorption. They are found in animal sources. The main compounds include retinol, the most bioavailable form; retinal, which is converted into other retinoids; and retinyl esters, which is the storage form of vitamin A.[3]
  • Carotenoids come from plants. They are less bioavailable because your body must convert them into retinoids for absorption. For example, carotenoid beta-carotene (from carrots, as an example) can become vitamin A, but first, it must be converted into retinal, and then again into retinol.[4][5]

Although retinoids are 6 times more bioavailable, carotenoids have unique, beneficial functions as antioxidants and may aid in the prevention of some chronic illnesses.[6]

Where to Get Vitamin A

Different food sources use different forms of vitamin A. Plants provide carotenoids whereas animal sources are high in retinoids. Examples of dietary sources rich in vitamin A include:[2][7] 

  • Liver
  • Eggs
  • Milk
  • Carrots
  • Sweet potatoes
  • Peppers
  • Kale

You can also get vitamin A in nutritional supplements. Supplementing your diet with vitamin A using MICROGEL™ technology is best for optimal absorption. This delivery system allows you to fully absorb nutrients into your bloodstream and then into your cells, where they work to improve health. Healthycell’s Bioactive Multi includes vitamin A in both carotenoid and retinoid forms pre-dissolved in sunflower oil and then suspended in a prebiotic gel for maximum absorption.

How Much Vitamin A Do You Need?

Everyone is different, and certain factors such as your age, sex, or health will affect your unique nutritional needs. To provide a general guide, the Food and Nutrition Board (FNB) established the Recommended Dietary Allowance (RDA) to meet the needs of most healthy individuals. Since the different forms of vitamin A are not equally absorbed, the RDA is expressed in micrograms of retinol activity equivalents (RAE) to account for the total vitamin content of the retinoid and carotenoid forms.[2]

Vitamin A RDA :

  • Infants (0 – 12 months):  400-500 mcg/day RAE
  • Children (1 – 8 years):  300-400 mcg/day RAE
  • Adolescents (9 – 18 years):  600-900 mcg/day RAE
  • Adults (19+ years):  700-900 mcg/day RAE
  • Pregnant and nursing women:  750-1,300 mcg/day RAE[2][8]

If you have a preexisting health condition or concern or take prescription medication, it’s important to talk to your doctor or registered dietitian about your nutrition, especially when choosing which supplements and dosages are optimal for your health.

Can You Take Too Much Vitamin A?

Since vitamin A is a fat-soluble vitamin that is stored in your body, it can become toxic when taken in large amounts. Toxicity is uncommon but can produce adverse effects, which is why a tolerable upper intake level (UL) has been established: 

  • Infants (0 – 12 months):  600 mcg/day RAE (2,000 IU)
  • Children (1 – 8 years):  600-900 mcg/day RAE (2,000-3,000 IU)
  • Adolescents (9 – 18 years):  1,700-2,900 mcg/day RAE (5,667- 9,333 IU)
  • Adults (19+ years):  3,000 mcg/day RAE (10,000 IU)
  • Pregnant and nursing women:  3,000-1,300 mcg/day RAE (10,000 IU)

Toxicity side effects can start with a harmless yellowing of the skin called hypercarotenemia. But more serious side effects can also develop. Excessive consumption can lead to a condition called hypervitaminosis A, which causes complications to eye, liver, and bone health. Other symptoms include nausea, drowsiness, headache, dry skin, hair loss, and muscle and bone pain.[9]

Vitamin A Deficiency — What Are the Symptoms?

Vitamin A deficiency is uncommon in the United States but more prevalent in developing countries due to the limited access to vitamin A rich foods. Deficiency may also be seen in individuals who consume vegetarian diets or struggle with alcoholism or drug abuse. Individuals with malabsorption conditions or those diagnosed with HIV/AIDS may also develop a vitamin A deficiency.[4]

Inadequate intake can lead to a weakened immune system, hardening or drying of the skin, or vitamin A deficiency disorder (VADD). VADD mostly affects children and is characterized by the following symptoms:

  • Dry eye
  • Night blindness
  • Permanent blindness
  • Bitot’s spots (white spots on the eye)

Vitamin A in Healthycell Products

Bioactive MultiBest for absorption!

The form of vitamin A contained in Bioactive Multi is beta-carotene from Blakeslea trispora and retinyl palmitate. The dosage of vitamin A in Bioactive Multi is 900 mcg, which satisfies 100 percent of the Daily Value (%DV).

Healthycell Pro

The form of vitamin A contained in Healthycell Pro is natural beta-carotene. The dosage of vitamin A is 2,500 IU in the morning formula and 2,500 IU in the evening formula, for a daily dosage of 5,000 IU, satisfying 100 percent of the Daily Value (%DV).

Healthycell

The form of vitamin A contained in Healthycell is retinyl palmitate. The dosage of vitamin A is 2,500 IU in the morning formula and 2,500 IU in the evening formula, for a daily dosage of 5,000 IU, satisfying 100 percent of the Daily Value (%DV).

Conclusions and Recommendations

  • Vitamin A needs to be present in your diet to support ocular health.
  • Vitamin A from retinoids is best for absorption, but carotenoid forms are also effective and function as antioxidants too, offering many additional health benefits.
  • Inadequate intake can lead to vitamin A deficiency disorder (VADD), which can result in blindness if not treated.

References

[1] McGuire, Michelle, PhD, and Kathy Beerman A., PhD. “Chapter 11 Fat Soluble
Vitamins.” Nutritional Sciences: From Fundamentals to Food. 2nd ed. Australia: Thomson/Wadsworth, 2007. 486-93. Print.
[2] “Vitamin A — Health Professional Fact Sheet.” U.S National Library of Medicine.
U.S. National Library of Medicine, 31 Aug. 2016. Web. 07 Sept. 2016.
[3] O’Byrne, Sheila M., and William S. Blaner. “Retinol and Retinyl Esters: Biochemistry
and Physiology Thematic Review Series: Fat-Soluble Vitamins: Vitamin A.” The Journal
of Lipid Research (2013): 1731-743. JLR. American Society for Biochemistry and Molecular
Biology, Inc. Web.
[4] Brasaemle, Dawn, PhD. “Vitamin A Lecture.” Rutgers University – Vitamin A. New
Brunswick. 2015. Lecture.
[5] Higdon, Jane, PhD, and Victoria Drake, PhD. “Carotenoids.” Oregon State University.
Linus Pauling Institute, 01 Jan. 2016. Web. 07 Sept. 2016.
[6] Balch, Phyllis A., CNC. Prescription for Nutritional Healing. 4th ed. New York: Avery, Print.
[7] Moore, Marisa, MBA, RDN, LD. “The Roles of Vitamin A.” Eat Right. Academy of
Nutrition and Dietetics, 15 Apr. 2014. Web. 07 Sept. 2016.
[8] Higdon, Jane, PhD, and Victoria Drake, PhD, and Barbara Delage, PhD. “Vitamin A.”
Oregon State University. Linus Pauling Institute, 23 June 2016. Web. 07 Sept. 2016.
[9] Ehrlich, Steven D., NMD. “Vitamin A (Retinol).” University of Maryland Medical
Center. N.p., 5 Aug. 2015. Web. 07 Sept. 2016.