Vitamin A deficiency: What It means for your vision and immune system

From childhood blindness to weakened immunity, vitamin A deficiency continues to affect vulnerable populations worldwide. Early action through diet and supplements can prevent lasting damage

Imagine struggling to see as daylight fades, or falling ill again and again, all because your body is missing one vital nutrient. That’s the harsh reality of vitamin A deficiency, a silent crisis affecting countless people worldwide. The World Health Organisation (WHO) warns that every year between 250,000 and 500,000 children lose their sight due to this deficiency, and tragically, about half of them die within just 12 months of going blind.

 

What is Vitamin A deficiency?

 

"Vitamin A is essential for good vision, a strong immune system, and overall health. It is present in foods such as carrots, leafy greens, and dairy products, making it easy to obtain through a well-balanced diet," said Dr Namrita Singh, associate director & unit head for internal medicine, Max Healthcare, Delhi. However, some people may not get enough due to poor nutrition, malabsorption disorders, or other health conditions.

 

Inadequate diet – Low intake of vitamin A-rich foods like dairy, eggs, fish, and leafy greens increases the risk, especially in areas with limited access to nutritious foods or among those on restrictive diets.

Poor absorption – Conditions such as liver disease, cystic fibrosis, inflammatory bowel disease, chronic diarrhoea or pancreatic disorders can reduce the body’s ability to absorb this fat-soluble vitamin.

Higher demand – Pregnancy, breastfeeding and infections raise the body’s vitamin A needs. If intake doesn’t match, deficiency can develop.

Prolonged malnutrition – Diets lacking fats, proteins and essential vitamins make it harder to maintain adequate levels over time.

Alcohol damage – Excessive drinking harms the liver’s ability to store and process vitamin A, causing a deficiency even when the diet is adequate.

 

Who is most at risk?

 

Vitamin A deficiency is especially common in low- and middle-income countries, particularly in parts of Africa and South-East Asia, says the United Nations Children's Fund (UNICEF). The groups most vulnerable are:

• Young children, especially preschool-aged, whose diets may lack enough vitamin A.
• Pregnant and breastfeeding women, because their own stores are tapped into for foetal development and to support breastmilk.
• Those suffering from infections like measles or diarrhoea, or conditions that impair nutrient absorption (for example, intestinal disorders), or liver disease.

 

Symptoms to watch out for

 

Vitamin A deficiency develops in stages. Some warning signs are subtle; others are serious. Here’s what may happen:

• Night blindness- difficulty seeing in low light.
• Bitot’s spots (foamy patches on whites of eyes).
• Xerophthalmia (very dry eyes),
• Corneal ulcers or keratomalacia (softening of the cornea), which can lead to blindness
• Increased susceptibility to infections, because vitamin A supports the immune system. A mild deficiency, even if not visibly obvious, increases the risk of disease and poorer recovery.
• Growth retardation in children.
• Complications during pregnancy, problems with lactation.
• Skin issues like dryness, rough patches.

 

"The severity of symptoms depends on how long the deficiency has been present and how low vitamin A levels have dropped," explained Dr Singh. 

Research suggests that vitamin A is involved in neural development, memory, and learning, she shared. "A deficiency can lead to cognitive impairment, difficulty concentrating, and, in some cases, mood changes such as irritability or depression. It may also contribute to an increased risk of neurodegenerative conditions. However, more studies are needed to fully understand the long-term impact of vitamin A deficiency on mental health," she said.

 

Diagnosis and treatment

 

Diagnosis typically involves:

• Checking medical history and physical symptoms like night blindness, dry eyes, etc.
• Blood tests to measure serum/plasma retinol.
• Eye examinations in severe cases.

 

Treatment:

• High-dose vitamin A supplementation over a short period, then follow-up dosing.
• Dietary improvement: include vitamin A-rich foods ( eggs, dairy, carrots, sweet potatoes, leafy greens, yellow/orange fruits).

"Conditions such as liver disease, cystic fibrosis, Crohn’s disease, and coeliac disease can interfere with the absorption of fat-soluble vitamins, including vitamin A. Managing these conditions with appropriate medication, dietary adjustments, and nutritional support can help improve vitamin A levels," added Dr Singh.

 

What you should do if you suspect deficiency 

• Consult a health professional. They can do diagnostic tests.
• Don’t self-prescribe high doses of vitamin A without guidance as too much can be toxic.
• Improve dietary intake right away, even before more severe signs develop.

Many effects can be reversed if the deficiency is caught early enough. However, damage to the cornea from advanced disease (like keratomalacia) may be permanent, shared Dr Singh.

 

How to avoid Vitamin A deficiency

 

Preventing vitamin A deficiency is usually more effective than treating it late. Experts suggest some strategies:

 

Balanced diet: Emphasising both preformed vitamin A and provitamin A carotenoids.

Food fortification: Adding vitamin A to staple foods where feasible.

Supplementation programmes: Particularly in regions with high deficiency rates, giving periodic vitamin A capsules to at-risk groups (children, pregnant women).

Public health interventions: Vaccination against measles, control of diarrhoeal disease, and improving sanitation. These help reduce losses and improve absorption.

 

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This report is for informational purposes only and is not a substitute for professional medical advice.