A vitamin A deficiency occurs when the body doesn’t get enough vitamin A, a fat-soluble vitamin. The human body does not produce vitamin A, so you must get it from your food. It’s important for healthy vision, a strong immune system, reproduction, and growth and development.
Most people in developed countries, such as the United States, get enough vitamin A in their diets, but deficiencies are not uncommon in developing countries. However, some people may be at greater risk of vitamin A deficiency regardless of where they live. A deficiency can occur if you are unable to get enough vitamin A from your diet or have trouble absorbing the vitamin.
This article reviews vitamin A deficiency, who is at risk, signs and symptoms, how to treat one, and more.
Getty Image / Kseniya Ovchinnikova
What Is a Vitamin A Deficiency, and Who Does It Affect?
Vitamin A deficiency occurs in someone who does not consume enough foods containing vitamin A or has trouble absorbing vitamin A in the gut. The deficiency mostly affects the eyes and eyesight possibly leading to blindness if not recognized and treated.
Deficiencies are more common in children living in developing countries. Isolated vitamin A deficiencies are rare in the United States. However, people with diseases or conditions affecting their gut are at a greater risk of developing vitamin deficiencies, including vitamin A.
It is rare that it is solely a vitamin A deficiency in this case. People with conditions affecting their gut are at risk of multiple vitamin deficiencies.
A vitamin A deficiency should be treated under the supervision of your primary healthcare provider. Deficiencies not confirmed and appropriately treated may result in long-term complications such as blindness, increased risk of lung infections, or more severe infections.
There are two sources of vitamin A available in the foods we eat:
- Preformed vitamin A is the source from animal products. This would be found in dairy products, eggs, meats, liver, and fish.
- Provitamin A carotenoids are plant pigments like beta-carotene. These come from plant sources of vitamin A. Once consumed, provitamin A carotenoids are converted into vitamin A in the body.
Causes and Risk Factors
Anyone who doesn’t eat enough foods that contain vitamin A or has trouble absorbing vitamin A is at risk of developing a deficiency. This may include the following groups:
- Premature infants in underdeveloped countries
- Pregnant or lactating individuals in low-income countries
- Children who live in underdeveloped countries
- Children who have avoidant/restrictive food intake disorder (ARFID) or other eating disorders
People with disorders of the gut or liver may also be at risk. These include:
- Celiac disease (immune reaction to the protein gluten found in wheat, barley, and rye)
- Cirrhosis (scarring of the liver) or disorders of the bile duct
- Cystic fibrosis (life-threatening condition of the lungs and digestive system) or pancreatic insufficiency (small intestine cannot digest food properly)
- Duodenal bypass, short bowel syndrome, or other malabsorption disorders
- Inflammatory bowel disease, including Crohn’s disease and ulcerative colitis
Signs and Symptoms
Vitamin A deficiency mostly affects the eyes and eyesight. Signs and symptoms of vitamin A deficiency may include:
- Bitot’s spots (irregularly shaped white deposits on the conjunctiva of the eye)
- Delayed growth in children
- Infection
- Infertility
- Night blindness (inability to see in levels of low or dim lights or at night)
- Poor wound healing
- Xerophthalmia (dryness of the conjunctiva and cornea of the eye)
Your primary healthcare provider can diagnose vitamin A deficiency. Diagnosis may be done by assessing the following:
- Medical history
- Diet history
- Physical exam
- Blood test
Complications
Vitamin A is a leading cause of preventable blindness in children worldwide.
Vitamin A deficiency mainly affects the eyes. The first sign of vitamin A deficiency is often night blindness. Xerophthalmia also negatively affects the cornea of the eye and can lead to irreversible blindness if left untreated.
Vitamin A deficiency can also contribute to an increased risk of infections. Furthermore, it has been associated with pregnancy deaths and negative outcomes related to pregnancy and lactation.
Treatment and Prevention
Treatment should always include education and counseling so that deficient individuals understand foods that should be included in the diet to get enough vitamin A. This may include working with a registered dietitian nutritionist (RDN).
The Food and Nutrition Board has set Recommended Daily Allowance (RDA) levels for vitamin A. This is the minimum amount needed to prevent a vitamin A deficiency.
| RDA for Vitamin A in Micrograms (mcg) of RAE (Retinol Activity Equivalents)) | ||||
|---|---|---|---|---|
| Age | Male | Female | Pregnant | Breastfeeding |
| 0–6 months | 400 mcg | 400 mcg | ||
| 7–12 months | 500 mcg | 500 mcg | ||
| 1–3 years | 300 mcg | 300 mcg | ||
| 4–8 years | 400 mcg | 400 mcg | ||
| 9–13 years | 600 mcg | 600 mcg | ||
| 14–18 years | 900 mcg | 700 mcg | 750 mcg | 1,200 mcg |
| 19–50 years | 900 mcg | 700 mcg | 770 mcg | 1,300 mcg |
| 51 years and older | 900 mcg | 700 mcg | ||
RAE is used because of the different bioactivities of retinol and carotenoids. One mcg of RAE is equivalent to:
- 1 mcg of retinol
- 2 mcg of supplemental beta-carotene
- 12 mcg of dietary beta-carotene
- 24 mcg of dietary alpha-carotene or beta-cryptoxanthin.
What Foods Contain Vitamin A?
Foods that are good sources of vitamin A include:
- Beans and nuts: Black-eyed peas and baked beans are particularly high in vitamin A, as are pistachios.
- Dairy products: Yogurt and some cheeses (ricotta) are good sources. Additionally, milk with added vitamin A is a great source.
- Fish: Fatty fish like herring, salmon, and tuna are excellent sources of vitamin A.
- Fruit: Mango, papaya, cantaloupe, and apricots are excellent fruit sources of vitamin A.
- Grains: This includes breakfast cereals may be fortified with vitamin A.
- Protein: Foods like chicken and egg provide some vitamin A. Liver is an excellent source of vitamin A and provides more than any other food.
- Tomato juice: Tomato products are nutrient-dense sources of vitamin A.
- Vegetables: Vegetables with red or orange pigment are great sources of vitamin A. These include carrots, bell peppers, sweet potatoes, squash, and pumpkin. Some green vegetables, like spinach and broccoli, are also good sources.
When Is Supplementation Recommended?
Vitamin A supplementation may be recommended during pregnancy and part of the prenatal supplement regimen recommended by obstetricians (specialists in a person’s health in pregnancy, childbirth, and postpartum). Maternal vitamin A supplementation has reduced the risk of preterm birth and neonatal (newborn) defects but increased birth weight in newborns.
Supplementation is recommended for suspected or confirmed vitamin A deficiencies. Your primary healthcare provider will recommend a high dose of supplemental vitamin A for a few days and then a lower dose until symptoms improve. Doses of vitamin A vary depending on the patient’s health and the severity of the deficiency.
For isolated vitamin A deficiencies, a single vitamin A supplement will work. Afterward, a multivitamin containing vitamin A may be enough for maintenance.
Your healthcare provider may recommend different supplement regimens for people with gastrointestinal (GI) disorders or medical conditions. For example, people with cystic fibrosis or pancreatic insufficiency may need all four fat-soluble vitamins supplemented. In this case, a supplement that provides a blend of vitamins A, D, E, and K in a water-soluble form may be prescribed.
There is no need to supplement vitamin A if you are not deficient.
Supplementing vitamin A should be done under medical supervision. Your healthcare provider can help you assess your vitamin A status and determine if vitamin A supplementation is appropriate for you.
How Long Does It Take to Correct a Vitamin A Deficiency?
Vitamin A deficiency and its symptoms can be treated and corrected if detected early. Supplementation can be prescribed by your healthcare provider to correct the deficiency.
With appropriate supplementation, symptoms like Bitot’s spots and night blindness can resolve in about two months. If the deficiency is left untreated, night blindness can advance to complete blindness that can not be corrected.
Aiding Vitamin A Absorption
Since vitamin A is a fat-soluble vitamin, it is important to include some healthy fats in your diet to help your body absorb it.
Oils like avocado, olive, or canola are healthy fats to include because they are mostly monounsaturated fats. Avocados and some nuts are also good sources of healthy fats.
Risks of Too Much Vitamin A
Taking excessive amounts of vitamin A over the long term can be detrimental.
As a fat-soluble vitamin, vitamin A is stored in the body, even in excess amounts. It can accumulate and lead to toxicity, referred to as hypervitaminosis A. This could happen days to weeks after taking very high amounts of vitamin A (100 times the RDA).
Signs of hypervitaminosis A may include:
- Blurred vision
- Dizziness
- Dry skin
- Fatigue
- Headache
- Liver enzymes that are abnormal on blood tests
- Muscle aches
- Nausea
Tolerable upper intake levels have been established by the Food and Nutrition Board for preformed vitamin A only (animal food sources and supplements). The upper limits vary depending on age and sex, but for adults, the limit is set at 3,000 mcg RAE.
It should be noted that vitamin A supplements may be a combination of preformed vitamin A and beta-carotene.
Some research suggests that other risks of supplemental vitamin A include:
- Higher rates of cancer in smokers when taking vitamin A supplementation, meaning current and former smokers should avoid vitamin A supplementation unless a deficiency is confirmed and supplementation recommended by your provider
- Increased mortality risk from heart disease and an increased lung cancer risk with beta carotene supplementation
Summary
Vitamin A is a fat-soluble vitamin, and most people get enough in their diet. However, a deficiency can occur when the body doesn’t get enough vitamin A to support its needs.
Vitamin A deficiencies are rare in developed countries, but they can happen. Like many other vitamins, some people are more at risk of deficiency and may benefit from supplementation. People with difficulty absorbing nutrients due to GI disorders are at a higher risk.
Vitamin deficiencies should be diagnosed and treated under medical supervision, as excessive amounts may pose risks.
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