Vitamin A Deficiency: Signs, Risks, and Prevention

What Is Vitamin A Deficiency and Why Does It Matter?

Vitamin A deficiency occurs when your body lacks the amount of vitamin A it needs to function properly. Your body cannot make vitamin A on its own, so you must obtain it through your diet. This nutrient is essential for healthy vision, metabolism, cell development, immune system function, and reproduction. When levels fall too low, these systems can begin to fail.

Worldwide, vitamin A deficiency is a major public health problem. According to the World Health Organization, it is the leading cause of preventable childhood blindness. Every year, an estimated 250,000 to 500,000 children who are vitamin A deficient become blind, and half of them die within 12 months of losing their sight. While deficiency is rare in the United States, it still affects certain groups. Globally, about one-third of children under five are estimated to be affected.

Sources: Cleveland Clinic, World Health Organization

Early Signs and Symptoms: From Night Blindness to Dry Skin

One of the earliest signs of vitamin A deficiency is night blindness, also known as nyctalopia. You may find it difficult to see in dim light or adjust from bright to dark environments. If left untreated, deficiency can progress to more severe eye conditions.

As deficiency worsens, the whites of the eyes and corneas can become dry, a condition called xerophthalmia. You might also develop foamy spots called Bitot spots on the whites of the eyes. In severe cases, corneal ulcers and keratomalacia (softening of the cornea) can occur, which can lead to permanent blindness.

Vitamin A deficiency also affects the skin. You may notice dry, scaly skin, and you may become more susceptible to infections. Because vitamin A supports immune function, deficiency can increase your risk of infections, particularly measles and diarrhea.

• Night blindness (difficulty seeing in low light)
• Dry eyes, which can progress to xerophthalmia
• Bitot spots (foamy patches on the eye)
• Corneal ulcers and keratomalacia (severe cases)
• Dry, scaly skin
• Increased susceptibility to infections

Sources: Cleveland Clinic, World Health Organization, Merck Manual

Who Is Most at Risk in the United States and Globally?

In the United States, vitamin A deficiency is rare in the general population, with an estimated prevalence of only 0.3% in 2013. However, certain conditions can increase your risk. These include inflammatory bowel disease (IBD), liver cirrhosis, and pancreatic insufficiency. For example, 16% of children with IBD have vitamin A deficiency at diagnosis. Among patients with liver cirrhosis eligible for transplant, the prevalence is as high as 70%. And 35% of those with chronic exocrine pancreatic insufficiency are deficient.

Any condition that impairs fat absorption can also lead to deficiency, since vitamin A is a fat-soluble vitamin. Such conditions include chronic diarrhea, celiac disease, cystic fibrosis, certain pancreatic disorders, bile duct blockage, and bariatric surgery. People with liver disorders that interfere with vitamin A storage are also at risk.

Globally, the burden is far heavier. In developing countries, infants, children, and pregnant or lactating women are most vulnerable. According to the World Health Organization, vitamin A deficiency is a public health problem in more than half of all countries, especially in Africa and South-East Asia. Pregnant women in these regions often experience night blindness, and deficiency contributes to maternal mortality and poor pregnancy outcomes.

Other risk factors include a severely restrictive diet, such as a vegan diet without adequate sources, and alcoholism. Premature infants are also at higher risk due to immature gastrointestinal tracts and low vitamin A stores.

• In the U.S., conditions like IBD, liver cirrhosis, and pancreatic insufficiency raise risk.
• Fat absorption issues from celiac, cystic fibrosis, or bariatric surgery increase risk.
• Globally, children under five and pregnant women in low-income countries are most affected.
• Vegans and those with alcoholism may also be at risk.

Sources: Cleveland Clinic, StatPearls Publishing, World Health Organization, Medscape

Health Consequences of Long-Term Deficiency

Chronic vitamin A deficiency can have serious and lasting health effects. The most well-known is vision loss, which can range from night blindness to complete blindness. While night blindness is often reversible with treatment, damage to the cornea from ulcers or keratomalacia may cause permanent scarring and irreversible vision loss.

Beyond vision, vitamin A is critical for immune function. Deficiency increases the severity and risk of infections, especially measles and diarrheal diseases. In children, this can be fatal. Long-term deficiency can also lead to growth issues in children and may contribute to infertility in adults.

The global burden of vitamin A deficiency has declined dramatically. One study reported that deaths attributable to deficiency decreased from 188,458 in 1990 to 17,374 in 2021. Disability-adjusted life years (DALYs) also fell from 18.79 million to 2.63 million over the same period. Despite this progress, vitamin A deficiency remains a public health problem in more than half of all countries.

Sources: Cleveland Clinic, World Health Organization, Frontiers in Nutrition

How to Prevent Deficiency with Food Choices

The best way to prevent vitamin A deficiency is to eat a balanced diet that includes foods rich in vitamin A. Vitamin A exists in two forms: preformed vitamin A (retinol) found in animal products, and provitamin A carotenoids (like beta-carotene) found in plant foods. Your body converts these carotenoids into vitamin A.

Good animal sources include liver, fish oils, eggs, and dairy products. Plant sources include orange and yellow vegetables and fruits, such as carrots, sweet potatoes, and mangoes, as well as leafy green vegetables like spinach and kale.

Because vitamin A is fat-soluble, your body needs dietary fat to absorb it properly. If you follow a vegan diet, including these colorful plant foods can help, but you may need to pay close attention to ensuring adequate intake. Avoiding excessive alcohol also helps protect your liver's ability to store vitamin A.

• Animal sources: liver, fish oils, eggs, dairy
• Plant sources: carrots, sweet potatoes, mangoes, spinach, kale
• Include some fat in meals to help absorption
• If you follow a vegan diet, focus on beta-carotene-rich foods

Sources: Cleveland Clinic, Medscape

When to See a Healthcare Professional

If you experience symptoms like night blindness, dry eyes, or frequent infections, consult a healthcare professional. Since vitamin A deficiency can be a sign of an underlying condition (such as a fat malabsorption disorder), proper diagnosis is important.

A healthcare provider can perform a blood test to measure serum retinol levels, though levels may not drop until deficiency is severe. They may also diagnose the condition based on an eye exam, looking for characteristic signs like xerophthalmia or Bitot spots.

Treatment for vitamin A deficiency typically involves high-dose supplements for several days, followed by lower doses until symptoms improve. However, if you have already developed corneal scarring, this damage is not reversible. Prompt treatment is essential to prevent permanent vision loss.

Always consult a professional before taking vitamin A supplements, as too much vitamin A can lead to toxicity.

Sources: Cleveland Clinic, StatPearls Publishing