Which Lack of Vitamins Causes Anemia? A Comprehensive Guide

January 3, 2026 •

3 min read

According to the World Health Organization (WHO), nutritional deficiencies, including a lack of folate and vitamin B12, are among the most common causes of anemia globally. This condition arises when your body lacks the essential vitamins needed to produce enough healthy red blood cells, leading to a host of debilitating symptoms.

Quick Summary

Anemia can be caused by deficiencies in vital nutrients like vitamin B12, folate (B9), and other key vitamins. These deficiencies disrupt the body's production of healthy red blood cells, resulting in a condition called megaloblastic anemia.

Key Points

Vitamin B12 and Folate are Key Culprits: Deficiencies in vitamins B12 and folate (B9) are the most common vitamin-related causes of megaloblastic anemia, where red blood cells are abnormally large.
Malabsorption is a Major Cause: Many cases, especially B12 deficiency, are not due to poor diet alone but rather conditions like pernicious anemia or Crohn's disease that prevent nutrient absorption.
B12 Deficiency Can Cause Neurological Damage: Unlike folate deficiency, a lack of vitamin B12 can lead to serious and potentially irreversible nerve damage, including tingling, numbness, and cognitive issues.
Other Vitamins Play a Supporting Role: While B12 and folate are primary, iron is the most common nutritional cause overall, and Vitamins A, C, and E can also impact red blood cell health.
Treatment Requires Specific Supplements: The correct treatment involves targeted supplementation (oral pills, injections) and dietary changes, and requires an accurate diagnosis to avoid exacerbating other deficiencies.
Certain Groups are at Higher Risk: Individuals on vegan diets, older adults, pregnant women, and those with gastrointestinal conditions are more susceptible to developing vitamin-deficiency anemia.

The Primary Causes: Vitamin B12 and Folate Deficiencies

The most common vitamin deficiencies that lead to anemia involve two key B vitamins: B12 (cobalamin) and B9 (folate). A lack of either can result in megaloblastic anemia, where the body produces abnormally large, immature red blood cells (megaloblasts) that cannot function correctly.

Vitamin B12 (Cobalamin) Deficiency

Vitamin B12 is essential for creating red blood cells, DNA synthesis, and maintaining healthy neurological function. A deficiency can lead to a type of megaloblastic anemia often accompanied by nervous system issues. Causes include pernicious anemia (an autoimmune disorder affecting B12 absorption), dietary factors (especially for vegans), malabsorption issues (like Crohn's or post-gastric surgery), and certain medications. Symptoms specific to B12 deficiency may involve neurological problems like numbness or tingling, difficulty with balance, and cognitive changes.

Folate (Vitamin B9) Deficiency

Folate is also critical for producing new red blood cells. A deficiency can develop relatively quickly. Causes include inadequate diet, alcohol misuse, increased demand (during pregnancy or certain medical conditions), and malabsorption issues. Unlike B12 deficiency, isolated folate deficiency typically doesn't cause neurological symptoms, though general anemia symptoms like fatigue are common.

Other Nutritional Factors Contributing to Anemia

Beyond B12 and folate, other nutrients are crucial for red blood cell health. While a mineral, iron is a key component of hemoglobin and its deficiency is the most prevalent form of anemia worldwide. Vitamin C supports iron absorption. Vitamin A deficiency can worsen anemia by impacting iron use. In rare cases, Vitamin E deficiency can cause hemolytic anemia, particularly in premature infants.

Comparison of Vitamin-Deficiency Anemias


Feature	Vitamin B12 Deficiency Anemia	Folate Deficiency Anemia
Primary Causes	Pernicious anemia, malabsorption, vegan diet, gastric surgery	Poor diet, alcohol misuse, pregnancy, certain medications
Symptom Onset	Develops slowly over months to years	Develops more quickly, within weeks
Neurological Symptoms	Yes; tingling, numbness, confusion, memory issues	Typically absent, though neuropsychiatric effects can occur in rare cases
Red Blood Cells	Abnormally large (macrocytic), oval-shaped	Abnormally large (macrocytic), oval-shaped
Treatment	B12 injections (for severe malabsorption) or supplements	Folic acid supplements, often for a few months

Diagnosis and Treatment

Diagnosis involves blood tests to determine the specific cause. A complete blood count (CBC) helps assess red blood cell size, and levels of B12 and folate are measured. Treatment varies:

For B12 deficiency: High-dose supplements or injections may be necessary, especially with malabsorption. Dietary changes are also advised.
For Folate deficiency: Folic acid tablets are standard, often taken for a few months, alongside increasing dietary folate.

It is important to correct B12 deficiency before treating folate deficiency alone, as folic acid can sometimes mask a B12 issue and allow neurological damage to progress.

Conclusion

Anemia can result from a lack of several vitamins, most commonly B12 and folate, which are vital for healthy red blood cell production. Deficiencies can stem from inadequate diet, malabsorption problems like pernicious anemia or Crohn's disease, or increased physiological needs during pregnancy. While iron is the most common nutritional deficiency related to anemia, other vitamins like A, C, and E also play roles. Proper diagnosis through blood testing is necessary to identify the specific vitamin deficiency, allowing for targeted treatment with supplements and dietary adjustments. Consulting a healthcare provider is essential for effective management and to prevent long-term complications, particularly neurological damage associated with untreated B12 deficiency.

For more information on general anemia, visit the official website of the World Health Organization.

Frequently Asked Questions

The vitamins most commonly associated with causing anemia are Vitamin B12 (cobalamin) and Vitamin B9 (folate). A deficiency in either can lead to megaloblastic anemia, where the body produces abnormally large red blood cells.

No, iron deficiency anemia is not a vitamin deficiency, as iron is a mineral. However, a severe lack of Vitamin C can indirectly contribute to iron deficiency because vitamin C helps the body absorb iron.

Both B12 and folate deficiency can cause megaloblastic anemia, but B12 deficiency can also lead to specific neurological symptoms like tingling, numbness, and memory issues. Folate deficiency typically does not cause these nerve problems.

People who are pregnant or breastfeeding, older adults, those with intestinal disorders like Crohn's or celiac disease, individuals on certain medications, and strict vegans or vegetarians are at higher risk.

Diagnosis involves blood tests ordered by a doctor. These tests check the size and shape of your red blood cells (CBC) and measure the levels of specific vitamins like B12 and folate in your blood.

Yes, anemia from vitamin deficiencies is treatable. Treatment typically involves supplementation with the deficient vitamin through tablets or injections, alongside dietary changes. Early and proper treatment is key, especially for B12 deficiency, to prevent irreversible nerve damage.

Pernicious anemia is a specific type of B12 deficiency caused by an autoimmune condition. The body's immune system attacks cells in the stomach that produce intrinsic factor, a protein necessary for absorbing B12 from food.

You can prevent many vitamin-deficiency anemias by eating a balanced diet rich in iron, vitamin B12, and folate. Foods like meat, fish, eggs, dairy, dark leafy greens, legumes, and fortified cereals are excellent sources.