Vitamin A deficiency: What you need to know

Despite not getting as much "publicity" as other vitamins (looking at you, vitamin C), Vitamin A is an essential vitamin—we can't make it and have to get it from our diet.

Vitamin A is particularly important when it comes to eye health, the immune system and reproduction. While a deficiency in this nutrient is rare in the United States, certain conditions can put people at a higher risk.

A deficiency in vitamin A may result in signs and symptoms that impact the following health categories:

Eye health
Vision impairment is the most common symptom of a vitamin A deficiency. In fact, the deficiency is the leading cause of preventable blindness in children all across the world.

Night blindness is an early sign of changes to vision and is also due to low vitamin A intake. Those with night blindness find it difficult to see in dark or dim light but can still see well if light is present.

As the deficiency worsens, the conjunctiva (tissue that covers the surface of the eye) dries out, and ulcers on the surface of the eye may appear. If left untreated, it can lead to vision loss and blindness.

Immune health
Because of the important role vitamin A plays in immune function, a vitamin A deficiency can lead to an increased risk of infections.

Skin health
Vitamin A deficiency and other nutritional deficiencies may contribute to phrynoderma or follicular hyperkeratosis. This condition occurs when too much keratin (a type of protein) builds up in the hair follicles.

Bone health
Poor bone growth may be a sign of a deficiency in vitamin A.

In the U.S., vitamin A deficiency is rare. It is seen more commonly in developing countries, where there is limited access to foods rich in vitamin A.

The U.S. is starting to see more vitamin A deficiencies and other nutrient deficiencies in those who have undergone bariatric (weight loss) surgery. This is due to the impact some types of bariatric surgery have on the absorption of vitamins.

Premature babies and people with cystic fibrosis, pancreatic disease and other conditions that impact fat digestion and absorption may also be at risk of a vitamin A deficiency.

Your healthcare provider can diagnose a vitamin A deficiency by taking a medical history (asking questions), doing an eye examination and taking blood for tests. Dietary supplements may be recommended to treat the condition, with the dosage being based on your age. While such supplements may be able to reverse night blindness and help eyes regain moisture, any vision loss from scarring due to corneal ulcers cannot be reversed.

Eating a well-balanced diet with foods rich in vitamin A can help prevent a deficiency for most individuals.

There are two forms of vitamin A available in the diet. The first is preformed vitamin A, which is found in animal sources, such as meat (especially liver), fish, dairy products and eggs. The second type is provitamin A carotenoids, and the most important carotenoid is beta-carotene. This is found in fruits and vegetables, especially leafy greens, broccoli, tomato products, and orange and yellow vegetables, such as squash, cantaloupe, sweet potato, pumpkin and carrots. Breakfast cereals are also often fortified with vitamin A.

The recommended daily amount of vitamin A is based on a person's age and sex. Too much vitamin A can be harmful, so supplements should be used with caution and only under the guidance of a healthcare provider.

If your healthcare provider thinks you're at risk of a deficiency, or you're concerned that your diet does not include enough vitamin A, it's best to talk with them before taking a supplement.

While unusual to see in the U.S., vitamin A deficiency can cause lasting damage to the eyes. For most people, making sure they eat a varied diet is the best way to prevent vitamin A deficiency.

Published July 2021.