What percentage of people have a folate deficiency?

December 1, 2025 •

5 min read

While folate deficiency has become rare in many higher-income countries with mandatory food fortification, often affecting less than 5% of the population, over half the world's population may still face folate inadequacy, according to recent findings. The wide range in statistics for what percentage of people have a folate deficiency highlights a significant global health disparity.

Quick Summary

Prevalence of folate deficiency varies drastically by region due to fortification efforts, impacting under 5% of people in some high-income nations versus over 20% in many low-income areas. Certain demographics, like women of reproductive age and individuals with specific medical conditions, remain at higher risk globally.

Key Points

Global vs. Fortified Countries: Folate deficiency is rare, affecting under 5%, in countries with mandatory food fortification, but remains high in many others, affecting potentially over half the world's population.
High-Risk Groups: Vulnerable populations include women of reproductive age, the elderly, those with alcohol use disorders, individuals with malabsorptive diseases like celiac disease, and people with certain genetic mutations or on specific medications.
Impact of Fortification: Mandatory fortification programs, like the one in the U.S. since 1998, have dramatically reduced folate deficiency rates in the general population.
Causes: Key causes range from poor dietary intake and malabsorption due to digestive diseases to increased physiological demands during pregnancy and impaired metabolism from alcohol or certain drugs.
Symptoms: Deficiency can lead to megaloblastic anemia, causing fatigue, weakness, paleness, irritability, and a sore tongue; in pregnancy, it can cause severe birth defects.

The question of what percentage of people have a folate deficiency is complex, with the answer depending heavily on location and specific population groups. In the United States and Canada, for example, widespread food fortification programs have drastically reduced the prevalence of clinical folate deficiency. However, in many other parts of the world, a significant portion of the population remains at risk. Understanding these regional differences and identifying high-risk individuals is crucial for effective public health interventions.

Global Prevalence: The Disparity Between Nations

According to an analysis of global folate status, the prevalence of folate deficiency varies dramatically across different economies. In countries with established food fortification programs, such as the United States, prevalence rates are very low, often under 5%. The CDC reports that in the U.S., deficiency rates for folate are less than 1% in the general population, a significant drop from pre-fortification levels. In contrast, a 2024 commentary in The Lancet Global Health highlighted that over half of the world's population, more than 4 billion people, may be affected by folate inadequacy, particularly women and children. In low- and middle-income countries, the prevalence of folate deficiency among women of reproductive age can exceed 20%, and insufficiency rates can be over 40%. This is largely due to the lack of mandatory fortification and lower dietary intake of folate-rich foods.

High-Risk Populations

Despite the success of fortification programs in reducing overall deficiency rates in some areas, certain groups remain at increased risk:

Women of reproductive age and pregnant people: Due to the five to ten-fold higher demand for folate during pregnancy, this group is particularly vulnerable. This risk is especially pronounced in regions without mandatory fortification and among women who do not take supplements. In the U.S., despite fortification, some women of childbearing age still have suboptimal folate levels.
Older adults: As a result of factors such as poor dietary intake, chronic medical conditions, and social isolation, elderly individuals face a higher risk. A U.K. study found prevalence rates of 10% in those over 75.
Individuals with alcohol use disorder: Chronic alcohol consumption interferes with folate absorption and metabolism, making deficiency more common in this population.
People with malabsorptive disorders: Conditions such as celiac disease and inflammatory bowel disease (IBD) can impair the absorption of folate. Studies show prevalence rates ranging from 11% to 49% in celiac disease patients and up to 28% in those with Crohn's disease.
Individuals with MTHFR polymorphism: A genetic mutation in the MTHFR gene can reduce the body's ability to convert folic acid into its active form, increasing the risk of deficiency.
Those on specific medications: Certain drugs, including some antiseizure medications like phenytoin and folate antagonists like methotrexate, can interfere with folate absorption or metabolism.

Causes of Folate Deficiency

The causes of folate deficiency are varied and often interconnected. They can be broadly categorized into:

Inadequate dietary intake: This is a primary cause, especially in populations with low access to fresh produce, fortified grains, or dietary supplements. Prolonged cooking can also destroy naturally occurring folate in foods.
Increased physiological requirement: Pregnancy, lactation, rapid growth in infancy, and conditions like hemolytic anemia significantly increase the body's need for folate.
Impaired absorption: Malabsorptive disorders like celiac disease and IBD, gastric surgeries, and certain medications can reduce the body's ability to absorb folate.
Increased excretion/loss: Renal dialysis can lead to excess folate loss. Excessive alcohol consumption increases excretion and interferes with liver uptake.

Comparison of Folate Deficiency Prevalence


Factor	High-Income Countries (with fortification)	Low/Middle-Income Countries (without fortification)	Special Populations (globally)
General Population Prevalence	Very low, typically <5% (e.g., <1% in U.S.)	High, often >20% in women of reproductive age	Much higher than general population in both contexts
Women of Reproductive Age	Suboptimal levels in some subgroups, despite fortification (e.g., 22.8% in U.S. study)	Significant deficiency and insufficiency (e.g., >20% deficiency, >40% insufficiency)	Higher risk due to increased demand during pregnancy
Older Adults	Riskier subgroups exist, particularly institutionalized individuals	At increased risk due to malnutrition and limited access to varied diet	5% (65-74 years) to 10% (>75 years) in a U.K. study
Associated Health Factors	Deficiency is often due to malabsorption, alcoholism, or genetics	Primarily due to low dietary intake and lack of access to supplements or fortified foods	Malabsorptive disorders, alcohol use, MTHFR polymorphism increase risk

Symptoms and Complications

Folate deficiency can cause megaloblastic anemia, where the body produces abnormally large, immature red blood cells. Symptoms of this anemia and deficiency can include:

Fatigue and weakness
Pale skin
Irritability
Headaches
Sore or smooth tongue (glossitis)
Reduced sense of taste
Diarrhea
In pregnant women, low folate levels dramatically increase the risk of the infant developing neural tube defects, such as spina bifida and anencephaly.

Diagnosis and Prevention Strategies

Diagnosing folate deficiency typically involves a combination of a thorough physical examination, dietary history, and laboratory tests. Blood tests for serum folate and red blood cell (RBC) folate can help determine a person's folate status, though serum levels can fluctuate with recent intake. Prevention strategies are crucial and differ based on regional factors. For the general population in many countries, mandatory food fortification, particularly in cereal grains, is highly effective. However, at-risk individuals and those in unfortified regions should focus on increasing their folate intake through diet and supplementation. A diet rich in leafy green vegetables, citrus fruits, legumes, and fortified cereals is recommended. Women of childbearing age are strongly advised to take a daily folic acid supplement in addition to a healthy diet.

For more detailed information, consult the NIH Office of Dietary Supplements Fact Sheet on Folate.

Conclusion

Ultimately, there is no single percentage to answer how many people have a folate deficiency; the number is highly variable. While fortification programs have made deficiency rare in some parts of the world, millions globally remain at risk due to a lack of these public health interventions. Vulnerable populations, including pregnant women, older adults, and those with specific health conditions, require particular attention to ensure they maintain adequate folate levels, regardless of location. Continuing to monitor global folate status and tailoring interventions is vital for preventing the associated health risks and achieving better health equity worldwide.

Frequently Asked Questions

Globally, the prevalence is highly variable and depends on a region's economic status and fortification efforts. Some data suggests over half the world's population may have folate inadequacy, with rates often over 20% in many low-income countries among women of reproductive age, compared to less than 5% in high-income countries with fortification programs.

Following the mandatory folic acid fortification of enriched cereal-grain products in 1998, the prevalence of clinical folate deficiency in the U.S. general population is now very low, reported by the CDC as less than 1%.

High-risk groups include women of childbearing age, pregnant and lactating individuals, older adults, people with alcohol use disorders, those with malabsorptive conditions like celiac disease or IBD, and individuals with a genetic MTHFR polymorphism.

Common symptoms include fatigue, weakness, irritability, pale skin, headaches, and a sore or smooth tongue. Severe deficiency can lead to megaloblastic anemia and, in pregnant women, increase the risk of neural tube defects in the fetus.

The main causes include inadequate dietary intake, impaired absorption due to medical conditions, increased physiological demand (e.g., pregnancy), increased excretion (e.g., alcohol use, dialysis), and certain medications that interfere with folate metabolism.

Mandatory food fortification programs have been highly successful in dramatically reducing the prevalence of folate deficiency in countries where they are implemented. For instance, the U.S. saw a sharp decline in low folate levels after its program began in 1998.

Diagnosis involves a physical examination and a review of the patient's dietary history and medications. Blood tests, including measurements of serum folate and red blood cell (RBC) folate, are used to confirm the deficiency.