There are two types of vitamin A found in foods: preformed vitamin A and provitamin A (1).
Preformed vitamin A is also known as retinol and commonly found in meat, fish, eggs and dairy products.
On the other hand, the body converts carotenoids in plant foods, such as red, green, yellow and orange fruits and vegetables, into vitamin A (2).
While deficiency is rare in developed countries, many people in developing countries do not get enough vitamin A.
Those at highest risk of deficiency are pregnant women, breastfeeding mothers, infants and children. Cystic fibrosis and chronic diarrhea may also increase your risk of deficiency.
Here are 8 signs and symptoms of vitamin A deficiency.
1. Dry Skin
Vitamin A is important for the creation and repair of skin cells. It also helps fight inflammation due to certain skin issues (3).
Not getting enough vitamin A may be to blame for the development of eczema and other skin problems (4).
Eczema is a condition that causes dry, itchy and inflamed skin. Several clinical studies have shown alitretinoin, a prescription medication with vitamin A activity, to be effective in treating eczema (3, 5, 6).
In one 12-week study, people with chronic eczema who took 10â€“40 mg of alitretinoin per day experienced up to a 53% reduction in their symptoms (6).
Keep in mind that dry skin can have many causes, but chronic vitamin A deficiency may be the reason.
Vitamin A plays an important role in skin repair and helps fight inflammation. A deficiency in this nutrient can lead to inflammatory skin conditions.
2. Dry Eyes
Eye problems are some of the most well-known issues related to vitamin A deficiency.
In extreme cases, not getting enough vitamin A can lead to complete blindness or dying corneas, which are characterized by marks called Bitotâ€™s spots (7, 8).
Dry eyes, or the inability to produce tears, is one of the first signs of vitamin A deficiency.
Young children in India, Africa and Southeast Asia who have diets lacking in vitamin A are most at risk of developing dry eyes (9).
Supplementing with vitamin A can improve this condition.
One study found that high doses of vitamin A decreased the prevalence of dry eyes by 63% among infants and children who took supplements for 16 months (10).
Vitamin A deficiency can lead to dry eyes, blindness or dying corneas, also known as Bitotâ€™s spots. One of the first signs of deficiency is often an inability to produce tears.
3. Night Blindness
Severe vitamin A deficiency can lead to night blindness (11).
Several observational studies have reported a high prevalence of night blindness in developing nations (12, 13, 14, 15).
Due to the extent of this problem, health professionals have worked to improve vitamin A levels in people at risk of night blindness.
In one study, women with night blindness were given vitamin A in the form of food or supplements. Both forms of vitamin A improved the condition. The womenâ€™s ability to adapt to darkness increased by over 50% over six weeks of treatment (16).
Getting adequate amounts of vitamin A is crucial for eye health. Some of the first signs of vitamin A deficiency are dry eyes and night blindness.
4. Infertility and Trouble Conceiving
Vitamin A is necessary for reproduction in both men and women, as well as proper development in babies.
If you are having trouble getting pregnant, a lack of vitamin A may be one of the reasons why. Vitamin A deficiency can lead to infertility in both men and women.
Studies show that female rats with vitamin A deficiency have difficulty getting pregnant and may have embryos with birth defects (17).
Other research suggests that infertile men may have a greater need for antioxidants due to higher levels of oxidative stress in their bodies. Vitamin A is one of the nutrients that acts as an antioxidant in the body (18).
Vitamin A deficiency is also related to miscarriages.
A study that analyzed the blood levels of different nutrients in women who had recurrent miscarriages found that they had low levels of vitamin A (19).
Both men and women who do not get adequate vitamin A can have fertility issues. Low vitamin A in parents may also lead to miscarriages or birth defects.
5. Delayed Growth
Children who do not get enough vitamin A may experience stunted growth. This is because vitamin A is necessary for the proper development of the human body.
Several studies have shown that vitamin A supplements, alone or with other nutrients, can improve growth. Most of these studies were conducted in children in developing nations (20, 21, 22, 23).
In fact, a study in over 1,000 children in Indonesia found that those with vitamin A deficiency who took high-dose supplements over four months grew 0.15 inches (0.39 cm) more than children who took a placebo (20).
However, a review of studies found that supplementing with vitamin A in combination with other nutrients may have a greater impact on growth than supplementing with vitamin A alone (22).
For example, children with stunted growth in South Africa who received multiple vitamins and minerals had length-for-age scores that were half a point better than those who received only vitamin A (23).
Vitamin A deficiency can cause stunted growth in children. Supplementing with vitamin A in combination with other nutrients may improve growth more than supplementing with vitamin A alone.
6. Throat and Chest Infections
Frequent infections, especially in the throat or chest, may be a sign of vitamin A deficiency.
Vitamin A supplements may help with respiratory tract infections, but research results are mixed.
A study in children in Ecuador showed that underweight children who took 10,000 IU of vitamin A per week had fewer respiratory infections than those who received a placebo (24).
On the other hand, a review of studies in children found that vitamin A supplements may increase the risk of developing throat and chest infections by 8% (25).
Furthermore, according to one study in elderly people, high blood levels of the provitamin A carotenoid beta-carotene may protect against respiratory infections (26).
Vitamin A supplements may protect underweight children from infections but increase the risk of infection in other groups. Adults with high blood levels of vitamin A may experience fewer throat and chest infections.
7. Poor Wound Healing
Wounds that do not heal well after injury or surgery may be linked to low vitamin A levels.
This is because vitamin A promotes the creation of collagen, an important component of healthy skin. Research suggests that both oral and topical vitamin A can strengthen skin.
A study in rats found that oral vitamin A improved collagen production. The vitamin had this effect even though the rats were taking steroids, which can inhibit wound healing (27).
Additional research in rats found that treating skin with topical vitamin A appeared to prevent wounds associated with diabetes (28).
Research in humans shows similar results. Elderly men who treated wounds with topical vitamin A had a 50% reduction in the size of their wounds, compared to men who did not use the cream (29).
Oral and topical forms of vitamin A can promote wound healing, especially in populations that are prone to wounds.
8. Acne and Breakouts
Since vitamin A promotes skin development and fights inflammation, it may help prevent or treat acne.
Multiple studies have linked low vitamin A levels to the presence of acne (30, 31).
In one study in 200 adults, vitamin A levels in those with acne were over 80 mcg lower than in those without the condition (30).
Topical and oral vitamin A may treat acne. Research shows that creams containing vitamin A can reduce the number of acne lesions by 50% (32).
The most well-known form of oral vitamin A used to treat acne is isotretinoin, or Accutane. This medication can be very effective at treating acne but may have a number of side effects, including mood changes and birth defects (33).
Acne has been associated with low vitamin A levels. Both oral and topical forms of vitamin A are often effective at treating acne but may have unwanted side effects.
Dangers of Too Much Vitamin A
Vitamin A is valuable to overall health. However, too much of it can be dangerous.
Hypervitaminosis A, or vitamin A toxicity, typically results from taking high- dose supplements over long periods of time. People rarely get too much vitamin A from diet alone (34).
Excess vitamin A is stored in the liver and can lead to toxicity and problematic symptoms, such as vision changes, swelling of the bones, dry and rough skin, mouth ulcers and confusion.
Pregnant women should be especially careful not to consume too much vitamin A to prevent possible birth defects.
Always check with your healthcare provider before starting vitamin A supplements.
People with certain health conditions may need a higher amount of vitamin A. However, most healthy adults need 700â€“900 mcg per day. Women who are nursing need more, while children need less (1).
Vitamin A toxicity usually results from taking too much of the vitamin in supplement form. It can cause serious issues, including vision changes, mouth ulcers, confusion and birth defects.
The Bottom Line
Vitamin A deficiency is prevalent in developing nations but rare in America and other developed nations.
Too little vitamin A can lead to inflamed skin, night blindness, infertility, delayed growth and respiratory infections.
People with wounds and acne may have lower blood levels of vitamin A and benefit from treatment with higher doses of the vitamin.
Vitamin A is found in meat, dairy and eggs, as well as red, orange, yellow and green plant foods. To make sure you get enough vitamin A, eat a variety of these foods.
If you suspect you have a vitamin A deficiency, talk to your doctor or healthcare provider. With the right foods and supplements, fixing a deficiency can be simple.