What Can Folic Acid Deficiency Cause?

November 14, 2025 •

5 min read

According to the CDC, mandatory food fortification has drastically reduced folic acid deficiency in many countries, yet certain populations remain at risk. Folic acid deficiency can cause a wide array of health problems, ranging from minor discomforts to severe developmental issues.

Quick Summary

Folic acid deficiency can lead to severe health issues, including megaloblastic anemia, birth defects, and increased cardiovascular risks. The condition also affects mood and cognitive function, with symptoms like fatigue, weakness, and mental fog. Recognizing the causes and risk factors is crucial for prevention and treatment.

Key Points

Megaloblastic Anemia: A common result of folic acid deficiency, causing fatigue, weakness, and shortness of breath due to the production of abnormally large, immature red blood cells.
Birth Defects: A deficiency in early pregnancy can lead to severe neural tube defects like spina bifida and anencephaly, affecting the baby's brain and spinal cord.
Cognitive and Mood Changes: Low folate levels are linked to depression, impaired memory, difficulty concentrating, and increased irritability.
Cardiovascular Risk: Folate deficiency causes elevated homocysteine levels, which is associated with an increased risk of heart disease and stroke.
Risk Factors: High-risk groups include pregnant women, people with celiac disease, individuals with chronic alcohol use, and those taking certain medications.
Treatment: Easily treated with folic acid supplements and dietary changes, but it's crucial to first rule out a concurrent vitamin B12 deficiency.
Prevention: Maintain a balanced diet rich in folate-rich foods like leafy greens and legumes, and consume fortified grains. Pregnant women and those who might become pregnant should take a daily folic acid supplement.

Understanding the Role of Folic Acid

Folic acid, also known as folate or vitamin B9, is a crucial nutrient required for a wide range of bodily functions. As an essential coenzyme in one-carbon metabolism, it is vital for DNA synthesis and repair, as well as for the creation of new red blood cells. Since the human body cannot produce folate on its own, it must be acquired through diet or supplements. Folic acid is the synthetic form of folate, commonly used in supplements and fortified foods due to its superior bioavailability. When the body's supply of folate is insufficient, a deficiency can develop, leading to numerous health complications.

The Impact of Deficiency on Blood Health

One of the most common and well-known consequences of folic acid deficiency is megaloblastic anemia. This condition arises when the body produces abnormally large, immature, and poorly-functioning red blood cells, known as megaloblasts. These cells are unable to carry oxygen effectively, leading to a host of symptoms:

Fatigue and Weakness: Reduced oxygen supply to tissues results in a constant feeling of tiredness and a lack of energy.
Pallor: The skin and mucous membranes may appear pale due to the low red blood cell count.
Shortness of Breath: The body attempts to compensate for the lack of oxygen-carrying capacity by increasing the respiratory rate.
Dizziness: Inadequate oxygen to the brain can cause lightheadedness and dizziness.
Heart Palpitations: The heart may beat faster or irregularly to pump more oxygen-rich blood.

Reproductive and Developmental Complications

Folic acid is especially critical for women who are pregnant or planning to become pregnant. A deficiency during early pregnancy can lead to severe birth defects known as neural tube defects (NTDs). NTDs include:

Spina Bifida: A condition where the spinal column does not close completely, leaving the spinal cord exposed. This can result in lifelong disabilities, including paralysis.
Anencephaly: A fatal condition in which a significant portion of the brain, skull, and scalp does not develop. Most infants with anencephaly do not survive past birth.

Beyond NTDs, folate deficiency during pregnancy can also increase the risk of other complications for both mother and child, such as preterm birth, low birth weight, and placental abruption.

Cognitive and Psychological Effects

Folate plays a role in neurotransmitter synthesis and methylation processes that affect brain health. A deficiency can cause a range of neuropsychiatric symptoms, though some severe neurological issues are more characteristic of vitamin B12 deficiency.

Depression: Studies suggest a link between low folate levels and an increased risk of depression.
Cognitive Decline: Impaired memory, poor concentration, and confusion are common symptoms, particularly in older adults.
Irritability: Mood changes and irritability are frequently reported.

Long-Term Risks and Other Issues

Elevated levels of homocysteine, an amino acid, are a marker of folate deficiency and are linked to various health problems. Left untreated, a deficiency can have chronic effects on overall health.

Cardiovascular Disease: High homocysteine levels can contribute to vascular endothelial dysfunction, increasing the risk of heart disease and stroke.
Certain Cancers: Emerging research suggests a potential link between folate status and certain cancers, though the relationship is complex.
Infertility: Folic acid deficiency has been associated with temporary infertility, which often resolves with treatment.
Gastrointestinal and Oral Symptoms: Individuals may experience a smooth, red, and swollen tongue (glossitis), mouth ulcers, and diarrhea.

Comparison of Folate and Vitamin B12 Deficiencies

Distinguishing between folate and vitamin B12 deficiencies is critical, as they present with overlapping symptoms but have different treatment approaches. Supplementing with folic acid alone in the presence of a B12 deficiency can mask the hematological symptoms while allowing neurological damage to progress unnoticed.


Feature	Folic Acid Deficiency	Vitamin B12 Deficiency
Primary Cause	Inadequate dietary intake (folate is water-soluble, so stores deplete quickly), malabsorption, or increased need (pregnancy).	Inadequate dietary intake (often in vegans/vegetarians), poor absorption (pernicious anemia), or certain stomach surgeries.
Associated Anemia	Megaloblastic anemia (abnormally large, immature red blood cells).	Megaloblastic anemia.
Neurological Symptoms	Generally absent in isolated cases, though neuropsychiatric symptoms like depression and cognitive issues can occur.	Common, and can be severe and irreversible if untreated. Includes numbness, tingling (paresthesia), memory loss, and balance problems.
Homocysteine Levels	Elevated.	Elevated.
Methylmalonic Acid (MMA)	Normal.	Elevated.
Treatment Risk	Folic acid supplementation can mask a coexisting B12 deficiency, worsening neurological damage.	Initial treatment may include injections followed by oral supplements; folic acid should not be given alone until B12 status is confirmed.

The Role of Fortified Foods and Supplements

Since 1998, the U.S. Food and Drug Administration (FDA) has required food manufacturers to add folic acid to common grain products, including bread, pasta, and cereals. This public health measure has been highly effective in reducing the incidence of NTDs. For individuals at higher risk, including pregnant women or those with specific medical conditions, supplementation is often recommended.

Commonly Fortified Foods:

Breads, flours, and cereals
Pasta and rice
Cornmeal

Naturally Folate-Rich Foods:

Leafy green vegetables (spinach, romaine lettuce)
Legumes (lentils, black-eyed peas)
Fruits (citrus fruits, bananas)
Eggs and beef liver

It is important to remember that prolonged cooking can destroy natural folate in foods.

Conclusion: Preventing and Treating Deficiency

Folic acid deficiency can cause significant health problems, from megaloblastic anemia to severe birth defects and neurological issues. The risks are particularly high during pregnancy, emphasizing the importance of adequate intake for women of childbearing age. While food fortification has played a crucial role in reducing deficiency rates, a balanced diet rich in folate and, in many cases, supplementation are necessary for maintaining healthy levels. Given the overlapping symptoms with vitamin B12 deficiency, it is vital to consult a healthcare provider for accurate diagnosis and appropriate treatment. Early detection and treatment can resolve symptoms and prevent long-term complications.

Preventative and Treatment Measures for Folic Acid Deficiency

Dietary Adjustments: Increase consumption of folate-rich foods like leafy greens, legumes, and fortified grains.
Supplementation: Take folic acid supplements, especially if you are pregnant, planning to become pregnant, or have a condition affecting absorption.
Limit Alcohol: Chronic alcohol use impairs folate absorption and metabolism.
Medical Consultation: Discuss any symptoms or risk factors with a doctor. Always check for a potential vitamin B12 deficiency before taking folic acid supplements.
Avoid Overcooking: Cook vegetables lightly, as high heat can destroy folate.

Recommended Daily Allowance of Folate


Group	Recommended Dietary Allowance (RDA)
Adults (14+ years)	400 mcg DFE/day
Pregnant women	600 mcg DFE/day
Lactating women	500 mcg DFE/day

For additional insights into folic acid metabolism and clinical implications, an authoritative source is the National Center for Biotechnology Information (NCBI) Bookshelf.

When to See a Doctor

Seek professional medical advice if you experience persistent symptoms of anemia, such as fatigue, weakness, or shortness of breath. It is particularly crucial for pregnant women or those planning a pregnancy to consult a healthcare provider about folic acid intake. A doctor can perform blood tests to confirm a diagnosis and rule out a concurrent vitamin B12 deficiency, which is essential for determining the correct treatment plan.

Frequently Asked Questions

Early signs of folic acid deficiency can be subtle but often include general symptoms of anemia, such as fatigue, weakness, and lack of energy. You might also notice a pale complexion, irritability, and a sore or red tongue.

Yes, a severe, long-term folic acid deficiency can cause temporary infertility. For both men and women, adequate folate levels are important for reproductive health. Fertility is likely to return to normal once the deficiency is treated.

Yes, folate is the naturally occurring form of vitamin B9 found in foods, while folic acid is the synthetic, man-made form. Folic acid is more easily absorbed by the body, which is why it's used in supplements and fortified foods.

Yes, chronic and excessive alcohol consumption is a significant risk factor for folic acid deficiency. Alcohol disrupts the absorption and metabolism of folate, and people who drink heavily often have a poor diet, further contributing to the problem.

A doctor can diagnose folic acid deficiency with a simple blood test that measures the amount of folate in your blood. During the diagnosis, it is crucial to also check for vitamin B12 deficiency, as the two can present with similar symptoms.

Foods naturally rich in folate include dark green leafy vegetables (spinach, broccoli), legumes (lentils, beans), citrus fruits, and eggs. Many grain products like cereals, bread, and pasta are also fortified with synthetic folic acid.

Yes, excessive folic acid intake from supplements can be a concern. Specifically, it can mask a vitamin B12 deficiency, allowing the associated neurological damage to worsen undetected. It is recommended not to exceed 1,000 mcg of folic acid daily unless prescribed by a doctor.