What causes a lack of vitamin A? Exploring the Root Factors

January 6, 2026 •

3 min read

According to the World Health Organization, vitamin A deficiency is a public health problem in more than half of all countries, particularly impacting young children and pregnant women. Understanding what causes a lack of vitamin A is crucial for prevention and mitigating its severe health consequences, including childhood blindness.

Quick Summary

Vitamin A deficiency results from inadequate dietary intake, malabsorption issues from certain health conditions, increased physiological demand during illness, and underlying liver disorders.

Key Points

Dietary Insufficiency: The most common global cause of VAD is simply not eating enough vitamin A-rich foods, particularly prevalent in low-income regions.
Malabsorption Syndromes: Chronic gastrointestinal diseases like cystic fibrosis, celiac disease, and Crohn's disease impair the body's ability to absorb the fat required for vitamin A absorption.
Increased Demand from Infections: Illnesses such as measles and chronic diarrhea increase the body's need for vitamin A and can rapidly deplete existing reserves.
Liver Impairment: Since the liver stores most of the body's vitamin A, liver diseases like cirrhosis and chronic alcoholism can severely hinder its storage and utilization.
Zinc and Protein Connection: Deficiencies in zinc or protein can indirectly cause or worsen VAD by affecting the synthesis and transport of retinol-binding protein.
Surgical Consequences: Procedures like bariatric surgery that alter the digestive tract to prevent fat absorption can significantly increase the risk of VAD.

Inadequate Dietary Intake

The most common cause of vitamin A deficiency (VAD) is insufficient intake from food. This is particularly prevalent in low-income areas with limited dietary diversity. Restrictive diets, like strict veganism, require careful planning to ensure adequate intake of provitamin A from plant sources, as animal products contain preformed vitamin A which is more readily absorbed. Prolonged malnutrition also significantly increases VAD risk.

Malabsorption Disorders

As a fat-soluble vitamin, vitamin A requires dietary fat for absorption. Conditions affecting fat absorption in the intestines can lead to VAD.

Chronic GI Illnesses

Diseases such as cystic fibrosis, celiac disease, and Crohn's disease damage the intestinal lining, impairing nutrient uptake. Chronic diarrhea increases nutrient loss, contributing to VAD, especially in children. Pancreatic insufficiency also hinders fat digestion necessary for vitamin A absorption.

Surgical Interventions

Abdominal and bariatric surgeries, particularly those involving small bowel bypass, can interfere with fat absorption and increase the risk of fat-soluble vitamin deficiencies, including VAD.

Increased Physiological Demand

Certain conditions or life stages increase the body's need for vitamin A.

Pregnancy and Lactation: Requirements are higher for pregnant and breastfeeding women to support both mother and infant. Insufficient maternal intake can impact breast milk vitamin A levels.
Infections: Severe infections like measles and persistent diarrhea deplete vitamin A reserves. This is linked to VAD weakening the immune system, making individuals more vulnerable to infections.

Liver Disorders and Alcohol Abuse

The liver stores significant amounts of vitamin A. Impaired liver function disrupts its storage and metabolism.

Liver Disease: Chronic liver diseases, including cirrhosis, affect the liver's ability to store and release vitamin A.
Alcohol Abuse: Excessive alcohol damages the liver and interferes with vitamin A metabolism.

Interaction with Other Nutrients

Deficiencies in zinc and protein can impair vitamin A absorption and transport. Zinc is vital for synthesizing retinol-binding protein (RBP), which transports vitamin A. Protein deficiency also suppresses RBP synthesis.

How Absorption Differs: Plant vs. Animal Sources


Feature	Animal Sources (Retinoids)	Plant Sources (Carotenoids)
Absorption Rate	Highly efficient, up to 70-90%	Lower and more variable, 20-50%
Source Type	Preformed vitamin A (retinol)	Provitamin A (e.g., beta-carotene)
Conversion	Requires no conversion; immediately available for use	Must be converted to retinol in the gut
Key Food Examples	Liver, eggs, dairy products, fish-liver oils	Carrots, sweet potatoes, kale, spinach
Vulnerability	Less vulnerable to malabsorption issues compared to plant sources	Absorption affected by fat intake and intestinal health

Conclusion

A lack of vitamin A often stems from a combination of inadequate diet and underlying health issues affecting absorption, storage, or utilization. Conditions like chronic illnesses, surgeries, and other nutrient deficiencies can disrupt vitamin A levels. Given the serious consequences of VAD, particularly for vulnerable groups, understanding these multifaceted causes is crucial for prevention and treatment. Individuals at risk should seek medical advice.

For more information, consult the National Institutes of Health (NIH) fact sheet on Vitamin A and Carotenoids.

At-Risk Populations

Key groups susceptible to vitamin A deficiency include:

Children under five: Especially in developing regions due to growth needs and infection risk.
Pregnant and breastfeeding women: Due to increased nutrient demands.
Individuals with malabsorption: Those with cystic fibrosis, celiac disease, or post-bariatric surgery.
People with liver disease: Conditions impairing liver's storage function.
Individuals with chronic alcoholism: Alcohol affects liver and vitamin A metabolism.
Those in low-income regions: Limited access to diverse, nutrient-rich foods.
Vegans: Requires careful dietary planning for sufficient intake from plant sources.

Frequently Asked Questions

Globally, the most common cause is inadequate dietary intake, particularly in low-income countries where access to diverse, nutrient-rich foods is limited.

Malabsorption disorders, such as cystic fibrosis, celiac disease, and chronic diarrhea, interfere with the body's ability to absorb fats. Since vitamin A is fat-soluble, this prevents its proper uptake from the digestive tract.

Yes, infections like measles and diarrhea can rapidly deplete the body's vitamin A reserves due to increased physiological demand and compromised immunity. This often creates a dangerous cycle of infection and deficiency.

Chronic alcohol abuse damages the liver, which is the body's main storage site for vitamin A. It also impairs the metabolism of vitamin A, disrupting its utilization and storage.

Zinc is necessary for the synthesis of retinol-binding protein (RBP), which transports vitamin A from the liver. Without enough zinc, this transport process is impaired, limiting the body's access to stored vitamin A.

Yes, pregnant and breastfeeding women have increased vitamin A requirements to support fetal and infant development. Children, especially in developing countries, are vulnerable due to rapid growth and higher risk of infections.

The liver stores most of the body's vitamin A. When liver function is compromised by conditions like cirrhosis, its ability to store and properly manage vitamin A is diminished, leading to deficiency.

Yes, bariatric surgeries like small bowel bypass are designed to limit nutrient absorption and can significantly increase the risk of fat-soluble vitamin deficiencies, including vitamin A.