Understanding the Root Causes: Why Does Vitamin A Deficiency Happen?

November 21, 2025 •

2 min read

According to the World Health Organization, vitamin A deficiency is the leading cause of preventable childhood blindness worldwide. Understanding why this deficiency happens is crucial for addressing its serious health impacts, which disproportionately affect vulnerable populations globally.

Quick Summary

Vitamin A deficiency results from inadequate dietary intake, impaired fat absorption due to certain medical conditions, and increased bodily demands during infections or life stages. Contributing factors include poverty and specific liver or gastrointestinal diseases.

Key Points

Inadequate Diet: The most widespread cause of vitamin A deficiency is insufficient intake of vitamin A-rich foods, particularly in impoverished regions.
Fat Malabsorption: Medical conditions like cystic fibrosis, celiac disease, and Crohn's disease can impair fat absorption, hindering the uptake of fat-soluble vitamin A.
Liver Impairment: Liver diseases, such as cirrhosis, interfere with the body's ability to store and release vitamin A, even if dietary intake is sufficient.
Increased Demands: Life stages like pregnancy and lactation, along with recurrent infections such as measles, significantly increase the body's requirement for vitamin A.
Associated Deficiencies: A concurrent zinc deficiency can impede the transport of vitamin A within the body, worsening the overall deficiency.
Socioeconomic Factors: Poverty and limited access to varied, nutritious foods are major drivers of deficiency, particularly in developing countries.

The Primary Causes: Inadequate Dietary Intake

For many populations around the world, the most common reason for developing a vitamin A deficiency is a simple lack of nutritious food.

Low Consumption of Vitamin A-Rich Foods

A diet low in diverse animal and plant sources can lead to deficiency, especially in regions relying on staple foods like rice that lack beta-carotene.

Poverty and Food Insecurity

Poverty limits access to varied, nutrient-rich foods, forcing reliance on less nutritious, inexpensive options, a major factor in deficiency globally.

The Secondary Causes: Malabsorption and Metabolic Issues

Even with sufficient intake, deficiency can occur if the body cannot absorb or process vitamin A, which requires dietary fat for absorption.

Conditions That Impair Fat Absorption

Conditions like cystic fibrosis, chronic diarrhea, inflammatory bowel diseases, pancreatic disorders, biliary obstruction, and certain bariatric surgeries impede fat digestion and absorption, affecting vitamin A uptake.

Other Related Factors

Liver Disorders: The liver stores most vitamin A, so conditions like cirrhosis impair this function.
Alcohol Use Disorder: Chronic alcohol use depletes liver stores and affects metabolism.
Zinc Deficiency: Zinc is essential for transporting vitamin A, so its deficiency can hinder utilization.

Increased Requirements and Vulnerable Populations

Increased bodily demands during certain periods or health events can heighten the risk of deficiency.

Pregnancy and Lactation: Higher needs support maternal and infant health.
Infants and Young Children: Rapid growth increases demands; deficiency can have severe consequences.
Chronic Infections: Infections like measles deplete stores and increase needs.

Comparison of Primary vs. Secondary Vitamin A Deficiency Causes


Feature	Primary (Dietary Insufficiency)	Secondary (Malabsorption/Metabolic Issues)
Underlying Problem	Lack of sufficient intake of vitamin A-rich foods.	Body's inability to absorb, store, or utilize vitamin A effectively.
Prevalence	Most common cause globally, particularly in developing nations with limited access to diverse diets.	Less common in developed nations, but a significant concern for specific at-risk groups.
Contributing Factors	Poverty, food insecurity, reliance on staple crops low in provitamin A (e.g., plain rice).	Medical conditions such as cystic fibrosis, Crohn's disease, celiac disease, liver disease, and alcoholism.
Typical Symptoms	Night blindness (often early symptom), xerophthalmia (dry eyes), increased infection risk.	Can present with classic vitamin A deficiency symptoms, but might also have signs related to the underlying malabsorption condition, such as chronic diarrhea or steatorrhea.
Solution	Increasing dietary intake of vitamin A-rich foods and/or mass supplementation programs.	Treatment requires managing the underlying medical condition in addition to vitamin A supplementation.

Conclusion

Understanding the diverse causes of vitamin A deficiency is vital for addressing this global health issue. Inadequate diet is the leading cause worldwide, while malabsorption and metabolic issues are significant factors in developed nations. Effective strategies require combining improved nutrition, public health programs, and medical management of underlying conditions. Consult authoritative resources such as the {Link: World Health Organization https://www.who.int/data/nutrition/nlis/info/vitamin-a-deficiency} for more information.

Frequently Asked Questions

The single most common cause of vitamin A deficiency worldwide is inadequate dietary intake, particularly in areas with food insecurity where diets lack sufficient vitamin A-rich animal and plant sources.

As a fat-soluble vitamin, vitamin A requires dietary fat for absorption. Conditions that interfere with fat digestion or absorption, such as cystic fibrosis, celiac disease, or chronic diarrhea, can lead to a secondary vitamin A deficiency.

Yes, chronic liver diseases like cirrhosis can cause a vitamin A deficiency. This is because the liver is the main storage site for vitamin A, and liver disorders disrupt its ability to store and release the vitamin into circulation.

Yes, pregnant and breastfeeding women are at a higher risk of vitamin A deficiency because of their increased nutritional requirements to support both their own health and the development of the fetus or infant.

Yes, infections like measles can significantly deplete the body's vitamin A reserves and are often more severe in individuals who are already deficient.

Zinc is needed for the synthesis of retinol-binding protein (RBP), which transports vitamin A from the liver to other tissues. A zinc deficiency can therefore impair this transport, hindering the body's ability to utilize its vitamin A stores.

Eating a balanced and varied diet is the best prevention. This includes consuming animal sources like liver and eggs for preformed vitamin A, and plant sources like carrots, sweet potatoes, and leafy greens for provitamin A carotenoids.