Vitamin A: What Does It Do & Why It Helps Your Eyes

Vitamin A is an essential nutrient that all humans need, and it plays an essential part in strong vision, a healthy immune system, body growth and reproduction. You can get the required amounts of vitamin A from certain foods or from supplements, but taking too much is unhealthy.

What Is Vitamin A?

Vitamin A is a fat-soluble nutrient found in animals and plants that we eat, and it is important for overall human health. One of the many roles vitamin A plays in the body is maintaining healthy vision. It helps prevent childhood blindness and is anecdotally thought to slow down age-related macular degeneration (AMD).

Vitamin A exists in two different forms — provitamin A carotenoids and preformed vitamin A (retinol). The former is present in plants. The latter is found in animals.

Preformed vitamin A is considered the active version of the vitamin because it is assimilated as is. Provitamin A carotenoids are converted into vitamin A in the body. They naturally exist in plant matter as beta-carotene, alpha-carotene and beta-cryptoxanthin. 

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What Does Vitamin A Do in the Body?

Besides maintaining your eyesight, vitamin A plays a role in many bodily processes. These include:

• Fetal growth and development. It helps maintain a healthy reproductive system and facilitates the growth of the fetus through several developmental stages.
• Skin health. It may prevent the overproduction of keratin in hair follicles, which is known to cause skin disorders like acne.
• Immune health. It is involved in the production of white blood cells, the first line of defense against pathogens in the body. 

Without question, the most notable benefit of vitamin A what it does to maintain eye health. It is involved in the production of a pigment found in the retina, which is responsible for how we perceive low light. As a result, one of the tell-tale signs of a vitamin A deficiency is night blindness.

Vitamin A is a critical nutrient during the early stages of life, particularly for vision. Insufficient vitamin A is the leading cause of preventable blindness during childhood. Many kids who experience childhood blindness show remarkable improvement after more vitamin A is added to their diet.

Despite an overwhelming amount of anecdotal evidence about the connection between vitamin A and a slower rate of progression of age-related macular degeneration, many studies show that there is nothing to suggest it can treat myopia or even slow down AMD.

How Vitamin A Helps with Your Eyes

Vitamin A plays a role in the manufacture of rhodopsin. Found in the eye’s retina, rhodopsin is a pigment that is highly sensitive to light and thus useful in low-light environments. Essentially, it helps you see better in the dark. 

This explains why people with vitamin A deficiencies first develop night blindness, a condition characterized by an inability to see properly in low-light environments. The absence of rhodopsin in adequate levels makes it harder for the retina to pick up on low Provitamin A carotenoids are converted into vitamin A in the body levels of light, causing temporary blindness in dark places.

Vitamin A can prevent blindness during childhood as it plays a vital role in eye development early on. However, many studies show that though it maintains eye health and could potentially stave off future complications, it has little to no effect on existing cases of myopia and AMD.

Consuming more vitamin A may improve your ability to see at night and keep your eyesight in mint condition, but it won’t alleviate existing eye disorders. Sticking to the recommended intake is still advisable because a vitamin A deficiency always leads to poorer eyesight.

Foods with Vitamin A

Animal and plant food sources give us different kinds of vitamin A. The type immediately assimilated by the body is known as preformed vitamin A or retinol. Good sources of retinol include:

• Eggs
• Oily fish
• Cheese
• Milk
• Yogurt
• Fortified spreads (low fat)
• Liver

Liver is a strong source of vitamin A, but it should be consumed cautiously. Pregnant women should stay away from liver and liver products such as pate.

Vitamin A also exists abundantly in the form of beta-carotene. The main sources of beta-carotene include:

• Green leafy vegetables (collard greens, kale, spinach, etc.)
• Red, orange, and yellow vegetables (carrots, red and yellow peppers, etc.)
• Sweet potatoes
• Yellow fruit (mango, apricots, pawpaws, etc.)

The recommended daily allowance (RDA) for vitamin A is 700 mcg for men and 600 mcg for women. Most people get all their vitamin A from their diet, but there are other ways to reach your RDA if food sources are unavailable.

Supplements

Vitamin A supplements can cover the deficit if food sources do not contain sufficient levels of the micronutrient. Nutritionists recommend that you do not exceed the RDA as excessive levels of vitamin A can be dangerous.

Examples of good vitamin A supplements include, but are not limited to:

• Fish liver oil
• Multivitamins
• Liver/liver pate
• Retinoid supplements

Do not take more than 1,500 mcg daily. Too much vitamin A can lead to osteoporosis. Supplements may not be necessary if you already eat liver or liver pate once a week.

References

1. Is Dietary Vitamin A Associated with Myopia from Adolescence to Young Adulthood? (May 2020).  Translational Vision Science & Technology.

2. Antioxidant vitamin and mineral supplements for preventing age-related macular degeneration . (July 2017). Cochrane Database of Systematic Reviews.

3. Intakes of Lutein, Zeaxanthin, and Other Carotenoids and Age-Related Macular Degeneration During 2 Decades of Prospective Follow-up. (December 2015). JAMA Ophthalmology.

4. Bioconversion of dietary provitamin A carotenoids to vitamin A in humans . (May 2010). The American Journal of Clinical Nutrition.

5. Vitamin A Deficiency and Clinical Disease: An Historical Overview. (October 2008). The Journal of Nutrition.