What Does a Lack of Folic Acid Lead To?

November 13, 2025 •

3 min read

According to the CDC, mandatory folic acid fortification of grain products has significantly reduced the incidence of neural tube defects since its introduction in 1998. A lack of folic acid can lead to serious health issues, including megaloblastic anemia and severe birth defects.

Quick Summary

Folic acid deficiency impairs DNA synthesis and cell division, causing megaloblastic anemia with fatigue and pale skin. In pregnant individuals, it significantly increases the risk of neural tube defects. The deficiency can also lead to oral issues, cognitive changes, and potential cardiovascular problems.

Key Points

Megaloblastic Anemia: A lack of folic acid impairs red blood cell production, leading to abnormally large, immature red blood cells and symptoms like fatigue, weakness, and paleness.
Neural Tube Defects: In pregnant individuals, a deficiency can cause serious birth defects, including spina bifida and anencephaly.
Elevated Homocysteine Levels: Insufficient folate can lead to high homocysteine, which is a risk factor for cardiovascular diseases like heart attack and stroke.
Cognitive and Mood Changes: The deficiency is linked to neuropsychiatric symptoms, including depression, irritability, and problems with memory and concentration.
Oral Symptoms: Common signs include a red and sore tongue (glossitis) and mouth ulcers.
Distinguishing from B12 Deficiency: While symptoms can overlap, a key difference is that neurological symptoms like tingling are specific to Vitamin B12 deficiency and are generally not a feature of isolated folate deficiency.

Understanding the Role of Folic Acid

Folic acid, also known as folate or vitamin B9, is a water-soluble B vitamin essential for several bodily functions, most notably the synthesis and repair of DNA and RNA. Because it is water-soluble, the body cannot store large amounts, which means it must be consumed regularly through diet or supplements. Folate is crucial for the formation of red blood cells, which carry oxygen throughout the body. When a deficiency occurs, these vital processes are disrupted, leading to a cascade of negative health consequences.

The Impact on Red Blood Cells and Anemia

A primary consequence of a lack of folic acid is megaloblastic anemia, a condition characterized by abnormally large, immature, and nonfunctional red blood cells.

Ineffective Erythropoiesis: Folate deficiency impairs the bone marrow's ability to produce healthy, mature red blood cells. Instead, it produces large, underdeveloped red cells known as megaloblasts.
Reduced Oxygen Transport: These abnormal red blood cells are less efficient at carrying oxygen. This leads to fatigue, shortness of breath, and pale skin, which are classic symptoms of anemia.
Other Blood Cell Effects: In severe cases, the deficiency can also impact other blood cell lines, potentially causing low levels of white blood cells and platelets (pancytopenia).

Complications During Pregnancy

Folic acid is especially critical for women of childbearing age and during pregnancy. Its role in rapid cell division and growth is vital for proper fetal development.

Neural Tube Defects (NTDs): A severe lack of folic acid before and during early pregnancy can lead to NTDs, which are major birth defects affecting the baby's brain and spinal cord. This includes spina bifida, where the spine doesn't close properly, and anencephaly, a condition where the brain and skull are underdeveloped.
Other Pregnancy Risks: Deficiency is also linked to an increased risk of premature birth, low birth weight, and placental abruption.

Neurological and Cognitive Effects

While neurological symptoms are more prominently associated with B12 deficiency, a lack of folic acid can also have significant neuropsychiatric effects.

Cognitive Impairment: Symptoms such as memory loss, difficulty concentrating, and confusion can arise from folate deficiency.
Mood Disorders: Low folate levels are linked to a higher risk of depression and irritability.
Psychiatric Symptoms: In some severe cases, psychosis and dementia-like symptoms have been observed.

Oral and Digestive Issues

The deficiency can also manifest through several symptoms affecting the mouth and digestive system.

Glossitis: A classic sign is a red, sore, and swollen tongue.
Mouth Sores: The presence of ulcers and sores inside the mouth can be a symptom.
Digestive Problems: Diarrhea and weight loss are also possible, particularly in severe, untreated cases.

Other Potential Health Risks

Beyond the more immediate symptoms, chronic folic acid deficiency poses several long-term health risks.

Cardiovascular Disease: Elevated homocysteine levels, a consequence of low folate, are associated with an increased risk of heart disease and stroke.
Increased Homocysteine: Folate is necessary to convert homocysteine into methionine. Without sufficient folate, homocysteine levels rise, which is damaging to blood vessels.
Certain Cancers: Some studies suggest a link between prolonged folate deficiency and a higher risk of certain cancers, such as colon cancer.

Comparison of Folate vs. Vitamin B12 Deficiency


Feature	Folic Acid Deficiency	Vitamin B12 Deficiency
Primary Effect on RBCs	Megaloblastic anemia (large, immature red blood cells)	Megaloblastic anemia
Neurological Symptoms	Generally absent, though neuropsychiatric symptoms can occur.	Prominent, including tingling, numbness, and balance issues.
Diagnosis	Low serum folate and high homocysteine with normal MMA levels.	Low serum B12 and high homocysteine with high MMA levels.
Treatment	Oral folic acid supplements.	Vitamin B12 injections or supplements.
Masking by Folate	Folic acid can mask B12 deficiency symptoms if not tested.	B12 supplementation does not mask folate deficiency.

Conclusion: The Critical Role of Folic Acid

The consequences of a lack of folic acid are far-reaching and can affect multiple bodily systems, with risks ranging from megaloblastic anemia and cognitive impairment to severe birth defects. While often treatable with supplementation, early diagnosis is key to reversing symptoms and preventing long-term damage. Public health initiatives, like grain fortification, have made significant strides in reducing deficiency rates, but awareness remains crucial for high-risk populations, including pregnant women, individuals with malabsorption disorders, and those with chronic alcohol use. Ensuring an adequate intake of folate-rich foods and supplements is a simple yet powerful way to safeguard your overall health.

For more detailed health information, consult reliable medical sources like the National Institutes of Health.

Frequently Asked Questions

The most common cause of folic acid deficiency is inadequate dietary intake of folate-rich foods, such as leafy green vegetables, legumes, and citrus fruits.

Yes, low folic acid levels have been linked to neuropsychiatric symptoms, including depression, irritability, and cognitive issues like memory problems and difficulty concentrating.

The first signs of folic acid deficiency are often mild and can include fatigue, weakness, and a lack of energy, often due to the development of anemia.

Isolated folic acid deficiency typically does not cause the severe neurological problems seen with B12 deficiency, such as numbness and tingling. However, neuropsychiatric symptoms like depression and confusion can occur.

Folic acid deficiency is typically diagnosed through blood tests that measure the level of folate in the blood. A complete blood count (CBC) can also reveal megaloblastic anemia, which is a sign of the deficiency.

Treatment involves taking folic acid supplements, often in oral form. A healthcare provider will determine the appropriate dosage, and dietary changes to include more folate-rich foods are also recommended.

Foods rich in folate include dark leafy green vegetables (like spinach and broccoli), citrus fruits, legumes (beans, peas, lentils), eggs, and fortified grains and cereals.